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Background and Objective: Considering the extensive cultivation of wheat in the drylands of Kermanshah province and farmers' lack of proper management of plant residues, it is necessary to think of a solution for the appropriate management of residues and wheat cultivation. For this purpose, an experiment was conducted to investigate the effect of different tillage systems on soil physical characteristics and quantitative traits of varying wheat cultivars in the drylands of the Dalahoo region. Materials and Methods: A split-plot experiment was conducted using a randomized complete block design with three replications. Tillage systems (conventional, reduced, and no-tillage) were investigated as main plots, and 26 wheat genotypes were analyzed as secondary plots. Soil physical characteristics and wheat yield and yield components were also investigated. Results: The results showed significant changes in the physical characteristics of the soil, the change of soil organic matter, and the yield and yield components of wheat. They were affected by tillage systems, genotype, and the interaction effect of tillage in genotype. The results showed that with increasing depth, soil temperature decreased, and soil moisture increased. Conclusion: In no-till cultivation, the change of soil organic matter was less than in other tillage systems. The highest wheat grain yield (6658 kg.ha-1 ) was under the interaction effect of the Mirzabey (Durum) genotype (genotype 24) in the no-tillage system. Conservation tillage proves the importance of residues on the soil surface in maintaining moisture in drylands, and probably in Dalahoo areas, conservation tillage methods are better for improving yield. [ABSTRACT FROM AUTHOR]

Background and Objective: This research was conducted in order to compare conservation tillage methods compared to conventional tillage on the moisture retention, organic matter and bulk density of the soil. Materials and Methods: Experiments were conducted on permanent raised bed (PRB), no-till with SFOGGIA (NT) and Jab Planter (JP) equipments, in a wheat- rapeseed-corn cropping system, during 2018-2020, as a randomized complete block design with three replicates in Yazd. Barzegar and Neptune cultivars and SC704 hybrid were used for wheat, rapeseed and corn, respectively. The examined characteristics included levels of soil moisture, bulk density and amount of soil organic matter. Results: Average of organic matter in 0-30 cm soil depth was increased from 0.23% at the beginning of experiment to 0.53%, 0.67% and 0.48% at the end of experiment in PRB, NT and JP treatments, respectively. The amount of soil organic matter in CT treatment was about 0.49% at the end of the experiment. The highest amount of available water was observed in PRB (0.207 %), CT (0.193 %) and JP (0.163 %) treatments, respectively. The lowest value of this parameter was observed in NT treatment (0.143%). The lowest value of the average bulk density of soil was observed in the CT treatment (1.47 g.cm³ ) and the highest value was observed in the NT treatment (1.60 g.cm³ ). Results showed significant differences among different tillage treatments in terms of wheat grain yield. Wheat grain yield in PRB treatment was significantly higher than the other treatments. The lowest wheat grain yield was obtained at NTs and NTj treatments. Wheat grain yield in CT, PRB and NTs and NTj treatments, were 4422, 5186,3762 and3547 kg.ha-1, respectively. The highest grain yield for rapeseed was obtained at CT and PRB treatments with no significant differences. The lowest grain yield was also observed for NTj treatment. The highest fresh weight of corn forage (71021 kg.ha-1 ) was observed in PRB treatment which was not statistically different from fresh weight in NTs and NTj treatments. The fresh weight of corn forage in CT treatment was 29% lower than fresh weight in PRB treatment. Conclusion: The use of conservation tillage methods and preservation of residues in the field can help to improve soil organic matter. Also, the average bulk density, water holding capacity, saturated moisture and field capacity moisture of the soil are strongly affected by the application of tillage methods and also the type of equipment used in tillage operation. [ABSTRACT FROM AUTHOR]

Background & Objectives: This research was conducted in order to investigate the effect of different mulches on weed biomass weight, yield and some physiological characteristics of onion. Materials & Methods: In order to investigate the effect of different mulches on weed biomass weight, yield and some physiological characteristics of onions, an experiment was conducted in a randomized complete block design with three replications at sample field in Jiroft area at 2019-2020 growing season. Experimental treatments included levels five inorganic mulch of black plastic, white plastic, organic mulch of wheat straw, weeding and control treatment. Traits such as plant height, bulb height, bulb diameter, neck diameter, bulb yield, TSS, bulb sulfur content, percentage of acid, soil temperature, soil moisture content and weed biomass weight were evaluated in three stages. Results:The results showed that all the studied traits except TSS were significantly affected by different mulches. The highest bulb height (73.1 mm), bulb diameter (69 mm), neck diameter (13.3 mm), bulb yield (55707 kg/ha), maximum temperature and soil moisture percentage were obtained in black mulch treatment. Thus, the bulb yield, bulb diameter and organic acids increased by 48.8%, 46.6% and 31.3% in the black mulch treatment, respectively. The highest amount of sulfur was observed in the straw and stubble treatment, There was no significant difference with black mulch treatment. Three types of dominant weeds such as wild mustard (Sinapis arvensis L.), malva (Malva neglecta L.) and leek (Chenopodium album L.) were observed in the studied onion field. The highest and lowest weed biomass of weeds were obtained in the first and third stages of sampling in control and black mulch. Conclusion:The results of this research showed that the improvement of quantitative and qualitative characteristics of onion was influenced by the type of mulch used. The use of appropriate mulch was effective in reducing the number and biomass of weeds and producing optimal yield of onion. According to the research results, black mulch treatment is the best treatment to control weeds and produce optimal yield. [ABSTRACT FROM AUTHOR]

One of the ways for measuring environmental parameters is using GNSS (Global Navigation Satellite System) reflected signals from the Earth surface that are received by GNSS antennas. Environmental parameters include soil moisture, seasonal snow accumulation, ice thickness, vegetation cover and water level changes in dams, lakes and seas (tide). The focus of this research is on soil moisture. Reflection of GNSS signals from a surface is called multipath. When the goal is positioning, multipath is one of the most significant sources of error in GNSS observations. But, by analyzing those reflected signals, we will get useful information about the reflection surface. This technique is called GNSS interferometric reflectometry (GNSS-IR). By this definition, GNSS-IR can be considered as a remote sensing technique for continuous and local monitoring of environmental parameters which can be performed in various weather conditions such as rainy and cloudy conditions, as well as different lighting conditions such as day and night. Signal-to-Noise Ratio (SNR) is a measure of the strength of a signal relative to the background noise level. In GNSS, SNR is used to evaluate the quality of the received signal. It is calculated as the ratio of the power of the received signal to the power of the noise in the receiver's bandwidth. Some of the receivers can also record SNR data which includes SNR component of reflected signals. In GNSS-IR, changes in soil moisture result in changes in the SNR component of the reflected signals. Specifically, as the soil moisture content increases, the dielectric constant of the soil increases, which causes the reflected signals to have higher amplitudes and higher SNR. Conversely, as the soil moisture content decreases, the reflected signals have lower amplitudes and lower SNR. Therefore, analyzing the SNR of the reflected signals can provide useful information about the soil moisture content. In addition to soil moisture, SNR can also be affected by other factors such as atmospheric conditions and receiver noise. Therefore, it is important to carefully analyze and process the SNR data to accurately estimate the soil moisture content. The soil moisture algorithm to be used in this study, is currently implemented at stations in the EarthScope PBO H2O network with the greatest variations in vegetation. Among the sites in the PBO H2O network, data from P038 in the New Mexico region is used. This site is located at in a flat area in a ecosystem characterized as grass land. SNR data from the new L2C signals are used by this site because the quality of the data are higher than those either the legacy L1 or L2P signals. The frequency of the L2C signal corresponds to a maximum penetration depth of 5 cm. The multipath signals are used to estimate soil moisture changes over a four-years period from 2017 to 2020. The calculations were done in four main steps. In the first step, appropriate satellite tracks with elevation angle between 5 to 30 degrees were selected and SNR data were extracted from RINEX files. In the second step the initial reflector height is estimated for each track and then the phase is obtained for each satellite track on each day. In the third step, SNR metrics are calculated, and finally, vegetation cover effects are removed and the result is converted to volumetric water content. According to the estimations, the volumetric water content in 2017 was 8.88%, which increased to 11.74% in 2018, then slightly decreased to 10.88% in 2019 and finally increased to 12.49% in 2020. In the fourth step, the effectiveness of the LSTM neural network model in predicting the time series of volumetric soil moisture obtained from GNSS-IR signals is investigated. The LSTM neural network can maintain its content over a long period of time and essentially remember previous information. This prediction will help farmers to prepare their irrigation schedules more efficiently. For this purpose, it is suggested to use cheap GPS receivers in agricultural lands in rural areas. The model is trained using 80% of station observations. By updating the network status with observed values instead of predicted values, the root mean square error decreased from 0.09 to 0.04, and the predictions became more accurate. Handling the location and type of receivers located in the Iranian Permanent GPS Network for Geodynamics (IPGN) and making the necessary settings in order to determine environmental parameters are suggested as byproducts for IPGN. Investigations have shown that performing GNSS observations produces more homogeneous reflective effects. Therefore, in order to increase the accuracy and quality of the results, it is suggested to use GNSS-IR instead of just GPS-IR. [ABSTRACT FROM AUTHOR]

Introduction: Soil moisture can be considered in the control of desertification, agricultural activities, watershed management and optimal management of water resources. Since the country of Iran is facing many problems in these fields, the expansion of studies in the field of accurate estimation of soil moisture becomes important (Mehrabi et al., 2019). The GLDAS system may have a high error compared to the measured data in some areas. Therefore, it is necessary before the data and results of this product are used as a decision-making tool in the region. The quality of these data should be evaluated locally using ground-measured data (Polo et al, 2016 & Sanchez-Lorenzo et al, 2013 & Zhang, 2019). In this study, Terra MODIS data was used to estimate soil moisture due to higher spatial resolution (1 km). Due to the fact that it is difficult to estimate the humidity time series in the field, and radar remote sensing methods produce humidity maps with low spatial resolution. Therefore, in this study, a new method was introduced to prepare a soil moisture map with higher spatial resolution based on NDVI and LST MODIS products. The purpose of this study is to estimate soil moisture in Jiroft city using the products of the Morris sensor and NDVI and LST indices. Considering that Jiroft plain is one of the agricultural poles of Iran. Estimating the time series of soil moisture and then providing a drought index based on soil moisture is a useful method for investigating agricultural drought in the study area. Results: LST and NDVI have high relative importance in arid regions (Park et al, 2016). In the study area, an algorithm based on remote sensing was used for soil moisture time series due to the lack of access to soil moisture time series. Moody's LST and NDVI products with a resolution of 1 square kilometer were used during 2007-2022. Then multiple linear regression was created using OLS method between soil moisture observations (2021 and 2022) and NDVI and LST time series data. Based on the results, both independent variables NDVI and LST were significant at the 99% level)p-value<0.01). VIF values were less than 10. Therefore, there is no linearity between the independent variables. The standard error is small, which indicates that the estimated value is exactly the true value. The value of t statistic of two variables is higher than 2, which is considered statistically significant. In general, R² = 0.78 and it shows the accuracy of soil moisture estimation method. R² was obtained as 0.74 and 0.8 in the years 2021 and 2022, respectively, which indicates the accuracy of the predicted values. Discussion & Conclusions: Estimation of spatial and temporal changes of soil moisture is an important issue in low data areas such as Iran. We proposed a multiple regression model based on Modis NDVI and LST to obtain surface soil moisture at a regional scale. The results showed that the multivariate linear regression method can be used to estimate soil moisture products with high resolution in areas with little data in the surface layers of the soil. Park et al. (2016) stated that LST and NDVI have high relative importance in arid regions. In the studied area, according to previous studies (Bai et al, 2020 & Wang et al, 2007), an algorithm based on remote sensing was used for soil moisture time series due to the lack of access to soil moisture time series became. Moody's LST and NDVI products with a resolution of 1 square kilometer were used during 2007-2022. Then multiple linear regression was created between soil moisture observations (2021 and 2022) and NDVI and LST time series data using OLS method. Based on the results of simulated soil moisture changes and the OLS method in estimating soil moisture (0-30 cm), both independent variables NDVI and LST were significant at the 99% level (p-value <0.01)). VIF values are less than 10 Therefore, there is no linearity between the independent variables. The standard error is small, which indicates that the estimated value is exactly the true value. The value of t statistic of two variables is higher than 2, which is considered statistically significant. Overall, R2 was 0.7 And it showed the accuracy of the soil moisture estimation method, which is consistent with the results of (Khanmohammadi et al, 2008 & Lin et al, 2015). [ABSTRACT FROM AUTHOR]

This study was conducted in the summer of 2021 to evaluate and validate the gravimetric soil water content measurements using a field oven. Ten soil types with a salinity of saturated paste (ECe) less than 4 dS m-1 and three saline soils were studied around Urmia Lake. Plots with dimensions of 1 m × 2 m were prepared for the selected soils to measure gravimetric soil water content and soil physical and chemical properties. The gravimetric water content (θm) values measured using the field oven (i.e., θmFO), were compared with those measured by a standard lab oven (i.e., θmLO). The soil water content values measured in the lab, regarded as a benchmark, were measured at 105 °C for 24 h. Temperatures of 120, 140, and 160 °C with three durations of 10, 15, and 20 min were used to dry the soil samples in the field oven. There was very good compatibility between the values of θmFO and θmLO when the soil samples were dried in the field oven for 15 or 20 min at all three temperatures. Significant linear relations were obtained between the θmFO and θmLO values as the slopes of linear relations were close to 1, the intercepts of relations were negligible and the distributions of measured data around the line 1 to 1 were unbiased. The minimal effects of soil organic matter content, clay content, salinity, and bulk density on water content measurements by the field oven indicate an important advantage of this method. These results confirm the high efficiency of the field oven for fast and reliable measurements of water content in different soils. [ABSTRACT FROM AUTHOR]

IntroductionPomegranate is a native fruit tree to Iran and has the best growth and performance in subtropical climate conditions. In recent years, due to environmental stresses conditions such as high temperature, high light intensity and low irrigation water a large number of orchards have faced to physiological problems such as fruit cracking, sunburn and a decrease in fruit quality. The high temperature along with high evaporation and transpiration can be considered as the main cause of these abnormalities, which causes disturbances in the process of plant metabolism and finally causes physiological disorders. Sunburn of the fruit is caused by high temperature and high sunlight intensity and has a negative effect on all the quality characteristics of the pomegranate fruit. Using net shade is one of the recommended ways to reduce the impact of climate change. Application of net shading in areas with high radiation levels has led to a decrease in the intensity of light radiation received by the canopy of the trees, which causes a decrease in the temperature of the leaf surface, and decrease the level of evaporation and transpiration in the trees. Materials and MethodsThis research was conducted during 2019-2020 for 2 years in a private orchard in the Kohmar area of Kazeron city of Iran. ́Rabab̕ pomegranate trees that were planted at a distance of 5 x 5 m and 15 years old were used. In this research, the effect of different types of net shading was investigated. The experiment was conducted as a randomized complete block design with 9 treatments and three replications in two years. The experimental treatments included the use of net shading in white and green colors with two different shading (30% and 50%) and two implementation methods (on the base and on the canopy of the tree) which were compared with control trees (without cover). During the growing season, measurements were made in relation to leaf temperature, sunlight intensity, soil moisture, relative water content of leaves, fresh and dry matter of leaves, and prolin content, and at the time of harvest, the percentage of sunburn, cracking and aril paleness of the fruit, thickness of fruit peel and anthocyanin content of fruit juice in all treatments were measured. Results and DiscusionsThe use of net shading increased the quantitative and qualitative characteristics of pomegranate fruits. The results of this research showed that the use of white and green nets 50% and green net 30% on the base had the best results. By using the appropriate type of net shading, the temperature of the pomegranate tree was reduced by about 6 degrees Celsius. Net shading also reduced the light intensity by at least 50%; the reduction of light intensity in green nets was more than in white nets.The highest relative water content was 85% in the green net shade (50% with base) treatment. Net shading significantly increased the water content of the leaves compared to the control.The use of net shading significantly reduced the percentage of sunburn on fruits compared to the control. Sunburn was about 14% in the control treatment and less than 5% in the net shading treatments. Net shading reduced the percentage of fruit cracking from 15 percent in the control treatment to about 7 percent in all shading treatments. ConclusionThe use of net shading as a cover for pomegranate trees reduces the temperature of the canopy of the plant by reducing the radiation of the sun, and by better maintaining the moisture of the soil of the pomegranate tree. It reduces the heat and drought stress condition and has a positive effect on the quantity and quality of the fruit produced. Among the treatments used, the use 3 types of net including 50% white nets on the base, and 30% and 50% green nets on the base had the best results. These treatments better than others in terms of shading percentage, temperature reduction, and improving the quantity and quality of pomegranate fruits . Net shading should be installed when the fruits are about 5 to 7 cm in diameter and will remain on the tree until mid-September. This type of tree shading did not leave any side effects on the quantity and quality of the fruits.

Due to the limited quality of water resources and considering that the majority of the country is arid and semi-arid, it is important to cultivate plants with a high tolerance to drought and salinity. This research was conducted to determine the effect of different moisture levels on yield and yield components of quinoa (Chenopodium quinoa Willd.) under lysimetric conditions in the spring and autumn cropping seasons. Treatments included irrigation after draining 0.2, 0.4, 0.6, and 0.8 of the total available water (TAW). Irrigation was done based on the soil moisture depletion and the leaching requirement of about 20%. At the end, dry biomass, seed yield, and yield components were measured. The results showed that with an increase in the moisture depletion from 0.6 to 0.8 TAW, the biomass and seed yield had a significant decrease of 24 and 37% in the spring and 34 and 47% in the autumn cropping season, respectively. But the increase in moisture depletion from 0.2 to 0.4 and 0.4 to 0.6 did not cause a significant decrease in these traits. The results indicated that changes in moisture depletion levels caused significant differences in plant height (P

Earth's climate is the result of complex interactions between its effective components and a function of solar radiation, which has a significant role on the afore said components. Among the most important climatic factors that are effective in the vegetation of humid, dry and semiarid regions, we can mention the variables of vapor pressure and soil moisture, which play an important role in the process of plant photosynthesis. Chlorophyll plays a significant role in photosynthesis of plants, including coniferous. According to the research conducted in Chitgar and Nowshahr, the effect of two different components has been evaluated. The effects of the season on the fluorescence value of two components can’t be denied. The highest value of correlation in soil moisture and its effect on the amount of fluorescence in Chitgar forest park in autumn and winter seasons is estimated with R²=0.44 and 0.56, respectively. The RMSE were calculated 7.4 and 6.7(mg/m2), respectively. In Nowshahr, the highest correlation value with total depth moisture was obtained in summer season. The numerical value of R² is calculated as 0.21. Also, P-Value is estimated at 0.498. The effects of environmental stresses on the amount of soil moisture in different depths are undeniable, especially in the seasons when the plant activity is high and the amount of photosynthesis will be more exposed to drought and salinity stresses. Regarding the effect of vapor pressure in Nowshahr, the highest degree of correlation has been calculated with the fluorescence value in the autumn season. The peak of the rainy season in the north of the country can be estimated in the autumn season, and with the increase in relative humidity, the water vapor pressure will increase.Introduction In recent years, new methods for application in various fields of science, including meteorologyagriculture, have gained special importance. Remote sensing is applied to estimate the sun's chlorophyll fluorescence. As matter of fact the climate of the earth is the sum of the interactions between its effective components and vegetation is considered one of its important and inseparable components, in the meantime, the process of photosynthesis is particular of importance. Materials and Methods The data required for the research, including the vapor pressure and soil moisture in the two considered stations, have been received from the National Meteorological Organization. Also, the amount of chlorophyll data of the vegetation cover of the two regions in question has been obtained through programming in Google Earth Engine and from the Sentinel 2 satellite. Considering that chlorophyll data related to vegetation is needed, the best index to obtain its data is MTCI (Meris Terrestrial Chlorophyll Index), which is used to estimate vegetation content from 2017. It has been used on the said satellite. But its data has gradually been made available to the public for use in research work since 2019. Results and Discussion The main process of material production in plants is carried out by photosynthesis, in which SIF plays a very important role. Choosing a strong representative in this direction to correctly calculate the amount of fluorescence has been a challenging issue. Chlorophyll fluorescence is estimated by the three principles of light distribution in leaves, light conversion by fluorescence emission and fluorescence diffusion through the plant canopy. The seasonal changes of SIF should be independent of the surface pressure or temperature because biotic and abiotic stresses are dependent on this issue according to the canopy structure and it is also different on a seasonal and daily scale and the results of seasonal changes originate from physiological changes. Remote sensing data is a good indication of photosynthetic activity. And in this research, the SIF satellite data shows a strong relationship between the photosynthetic capacity component using the above two areas and the coniferous cover of the two areas. It is worth noting that on a short scale, the variation in photosynthetic capacity is low and on a monthly and seasonal scale, it will be more in a time series that is determined by the enzyme RUBISCO in the photosynthetic scale. Conclusion Although it is not easy to fully distinguish the effect of vapor pressure and soil moisture from each other and their effect on the SIF value and finally the plant cover performance, but the effect of these two components on the coniferous plant cover in the two different climates mentioned above is quite evident. According to the analyzes carried out in the climate of Chitgar region, two factors, vapor pressure and soil moisture, are considered as limiting factors in plant photosynthesis, and the lack of any of these factors can seriously damage the photosynthetic performance of coniferous. Leave this area, which will then overshadow the biomass above the surface and the amount of chlorophyll fluorescence. The effect of each season, due to the presence of biotic and abiotic stresses, affects the amount of chlorophyll or vegetation, and will ultimately overshadow the photosynthetic performance of coniferous vegetation. For example, in arid and semi-arid regions, salinity stress is one of the most important stresses, the accumulation of salt caused by irrigation in the surrounding environment of the roots and the increase in water-soil potential are among the damages that are caused to the roots of these plants. . In addition, the most damage in salinity stress will be done to the aerial organs of the plant, including leaves, which play a significant role in photosynthesis. [ABSTRACT FROM AUTHOR]

Drought is a costly natural hazard with wide-ranging consequences for agriculture, ecosystems, and water resources. The present study aims to investigate droughts in Iran using multi-variable indices. The data used includes soil moisture network data and monthly precipitation from the MERRA center over a 43-year period (1980-2022). Based on soil moisture and precipitation data, the results of a drought calculation in Iran demonstrated that droughts occur throughout the country with varying degrees of severity and weakness. Their occurrence has become a permanent feature of the country's climate, particularly in recent decades. The analysis of Iran's drought chronology revealed that, according to the MSDI index's range, most of the country's droughts are weak and moderate. It was also discovered that as time scales increase, the frequency of droughts decreases while the continuity, magnitude, and severity increase. [ABSTRACT FROM AUTHOR]

Improving soil physical properties and increasing water retention in the soil are management strategies in soil and water conservation and enhancing crop yield in rainfed lands. This study was conducted to investigate the role of tillage direction and wheat stubble mulch level in improving soil physical properties in rainfed land in Zanjan province. A field experiment was done at two tillage directions: up to the downslope and contour line, and five stubble mulch levels: zero, 25, 50, 75, and 100% of land cover equal to 6 tons per hectare. A total of 30 plots (2 m×5 m) were created. The results indicated that water infiltration and water content were considerably affected by tillage direction, whereas its effect on water holding capacity was not significant. This physical property of the soil was influenced by the inherent properties of the soil, including particle size distribution. The change of up to down tillage direction to the contour line increased soil infiltration to 11% and water content to 6%. The physical soil properties were wholly influenced by mulch consumption. Soil water content increased in mulch treatments along with water holding capacity and infiltration rate. The highest volumetric water content was at 100% mulch level (10.62%) which was 11% more than the control treatment. However, there was no significant difference between 100% and 75% mulch treatment. This revealed that the application of 75% stubble mulch in contouring tillage is a substantial strategy for improving soil physical properties and controlling water loss in rainfed lands of semi-arid regions.

The aim of this study was to evaluate the effectiveness of estimated soil moisture data obtained from the GLDAS, ESA and SMAP sensor databases with the observed data of the Silakhor Agricultural Meteorological Station to investigate the spatial and temporal variation of soil moisture in Lorestan province. The data used in this research include the soil moisture data of the Silakhor station, GLDAS database, ESA center and SMAP sensor products during a six-year period (2016-2021). Estimated soil moisture data were evaluated against observed data using R2, RMSE and MAD statistics. The results showed that the SMAP satellite is associated with underestimation and the GLDAS model and the ESA satellite are associated with overestimation of soil moisture. However, in general, the estimated soil moisture values of the three mentioned sources have good accuracy. The value of the correlation coefficient between observed soil moisture data with soil moisture data obtained from SMAP and ESA satellites and GLDAS model was obtained as 0.62, 0.59 and 0.72 respectively, and in the combined case (SMAP, ESA and GLDAS) the value of correlation coefficient was increased to 0.77, therefore, it is suggested to use combine data to use soil moisture estimation.

In Iran, pressurized irrigation systems cover a large area of agricultural land, but water use efficiency remains low because farmers tend to do deficit (over) - irrigation due to their lack of knowledge of crop water requirements. To address this issue, irrigation systems can be automated, and it is important to estimate crop water requirements accurately. This can be done based on soil moisture deficit or meteorological data. The water required can then be applied using a volume meter or by determining irrigation time based on the sprinkler flow rate. The study aimed to compare crop water requirement estimates based on soil moisture deficit and meteorological data, as well as the amount of water applied using volume and time-based methods.The study was conducted in the research farm of Razi University, Kermanshah, Iran, on a sprinkler irrigation system equipped with pressure and flow measuring devices, pressure switches, and electrical valves. The field was under corn cultivation, and four types of irrigation management were evaluated, which included a combination of two methods of determining crop water requirement (soil moisture deficiency and meteorological data) and two methods of irrigation application (time or volume). The four treatments were soil moisture - time (MT), soil moisture - volume (MV), weather - time (WT), and weather - volume (WV). The crop water requirement was calculated using the Penman-Monteith formula based on daily weather data. Soil moisture was measured at different depths one day before irrigation, and the soil moisture deficit was calculated to determine the crop water requirement based on soil moisture. The irrigation volume for each sprinkler in the irrigation cycle was calculated using equations that written in the paper.In the volumetric-based method (treatments WV and MV), the volume of water applied was measured using a water meter with a precision of 0.1 liters, and irrigation was stopped after passing the required volume of water. In the time-based method (treatments WT and MT), the irrigation time was calculated by dividing the irrigation volume by the average flow rate of the sprinklers (3 liters per second), and irrigation was stopped after the calculated duration. The actual sprinkler flow rate was calculated based on the volume of applied water and irrigation time in each treatment and irrigation round. Crop yield was measured at the time of harvest in the studied treatments and a control treatment managed by the Faculty of Agriculture. The irrigation treatments were not applied in the first month of the growth period due to field limitations.The results show that the crop water requirement calculated based on meteorological data at the beginning and end of the growing period was more than the method based on soil moisture. In total, the amount of crop water requirement calculated based on soil moisture was 8% more than the meteorological-based method. The volume of applied water in treatments of MT and WT was 14 and 8% more than in MV and WV treatments, respectively.The actual flow rate of sprinklers was different from the design flow rate due to irrigation situations in other parts of the farm. The average discharge of sprinklers (12 irrigation events) in WT, MT, WV, and MV treatments was 2.79, 3.03, 3.27, and 3.12 l/s, respectively. The irrigation time in volume and time-based methods also showed a significant difference. The irrigation time in MT and MV treatments was 10 and 18% longer than in WT and WV treatments, respectively. The study found that due to the non-uniformity of sprinkler discharge, applying irrigation by volume method is better than the time-based method. The results suggest that the MV treatment, which determined the amount of irrigation based on soil moisture deficit and applied it using a volumetric method, is a suitable option for automating sprinkler irrigation systems in the studied region.

In Iran, pressurized irrigation systems cover a large area of agricultural land, but water use efficiency remains low because farmers tend to do deficit (over) - irrigation due to their lack of knowledge on crop water requirements. To address this issue, irrigation systems can be automated, and it is important to estimate crop water requirements accurately. This can be done based on soil moisture deficit or meteorological data. The water required can then be applied using a volume meter or by determining irrigation time based on sprinkler flow rate. The study aimed to compare crop water requirement estimates based on soil moisture deficit and meteorological data, as well as the amount of water applied using volume and time-based methods. Methodology The study was conducted in the research farm of Razi University, Kermanshah, Iran, on a sprinkler irrigation system equipped with pressure and flow measuring devices, pressure switches, and electrical valves. The field was under corn cultivation, and four types of irrigation management were evaluated, which included a combination of two methods of determining crop water requirement (soil moisture deficiency and meteorological data) and two methods of irrigation application (time or volume). The four treatments were soil moisture - time (MT), soil moisture - volume (MV), weather - time (WT), and weather - volume (WV). The crop water requirement was calculated using the Penman Monteith formula based on daily weather data. Soil moisture was measured at different depths one day before irrigation, and the soil moisture deficit was calculated to determine the crop water requirement based on soil moisture. The irrigation volume for each sprinkler in the irrigation cycle was calculated using equations 1 and 2. V= ∑i=1n ETci* sm*si/ea Method 1: Based on meteorological data (2) V = d*sm*si/ea Method 2: Based on soil moisture deficiency where V is the irrigation volume, d is the water deficit depth in the root zone, n is the number of days after the previous irrigation, and Sm and Sl are the distance between the laterals and sprinklers respectively (21 m * 21m), and ea is the irrigation application efficiency (0.8). In the volumetric-based method (treatments WV and MV), the volume of water applied was measured using a water meter with a precision of 0.1 liters, and irrigation was stopped after passing the required volume of water. In the time-based method (treatments WT and MT), the irrigation time was calculated by dividing the irrigation volume by the average flow rate of the sprinklers (3 liters per second), and irrigation was stopped after the calculated duration. The actual sprinkler flow rate was calculated based on the volume of applied water and irrigation time in each treatment and irrigation round. Crop yield was measured at the time of harvest in the studied treatments and a control treatment managed by the Faculty of Agriculture. The irrigation treatments were not applied in the first month of the growth period due to field limitations. Results and discussion The results show that the crop water requirement calculated based on meteorological data at the beginning and end of the growing period was more than the method based on soil moisture. In total, the amount of crop water requirement calculated based on soil moisture was 8% more than meteorological based method. The volume of applied water in treatments of MT and WT was 14 and 8% more than in MV and WV treatments, respectively. The actual flow rate of sprinklers was different from the design flow rate due to irrigation situations in other parts of the farm. The average discharge of sprinklers (12 irrigation events) in WT, MT, WV, and MV treatments was 2.79, 3.03, 3.27, and 3.12 l/s, respectively. The irrigation time in volume and time-based methods also showed a significant difference. The irrigation time in MT and MV treatments was 10 and 18% longer than in WT and WV treatments, respectively. The final grain yield, applied water, and crop water productivity (based on the treatment application period) are presented in Conclusions The study found that due to the non-uniformity of sprinkler discharge, applying irrigation by volume method is better than the time-based method. The results suggest that the MV treatment, which determined the amount of irrigation based on soil moisture deficit and applied it using a volumetric method, is a suitable option for automating sprinkler irrigation systems in the studied region. [ABSTRACT FROM AUTHOR]

Improving soil physical properties and increasing water retention in the soil are management strategies in soil and water conservation and enhancing crop yield in rainfed lands. This study was conducted to investigate the role of tillage direction and wheat stubble mulch level in improving soil physical properties in rainfed land in Zanjan province. A field experiment was done at two tillage directions: up to the downslope and contour line, and five stubble mulch levels: zero, 25, 50, 75, and 100% of land cover equal to 6 tons per hectare. A total of 30 plots (2 m×5 m) were created. The results indicated that water infiltration and water content were considerably affected by tillage direction, whereas its effect on water holding capacity was not significant. This physical property of the soil was influenced by the inherent properties of the soil, including particle size distribution. The change of up to down tillage direction to the contour line increased soil infiltration to 11% and water content to 6%. The physical soil properties were wholly influenced by mulch consumption. Soil water content increased in mulch treatments along with water holding capacity and infiltration rate. The highest volumetric water content was at 100% mulch level (10.62%) which was 11% more than the control treatment. However, there was no significant difference between 100% and 75% mulch treatment. This revealed that the application of 75% stubble mulch in contouring tillage is a substantial strategy for improving soil physical properties and controlling water loss in rainfed lands of semi-arid regions. [ABSTRACT FROM AUTHOR]

Introduction Agriculture plays an essential role in providing food, and in order to achieve sustainability in the agricultural sector, resources must be used in the best possible way. In order to achieve the maximum possible yield, it is necessary for the crop plant to use the environmental factors, water, nutrients, light, and carbon dioxide, with the maximum possible efficiency. The maximum use of the required factors for growth is achieved only when the plant community exerts maximum pressure on these factors. In general, intercropping is one of the ways to achieve sustainable agriculture, with higher yields without increasing agricultural inputs, absorption, and environmental factors productivity. Researchers for the intercropping of corn and mung bean have reported that the mixed cultivation systems used environmental resources more effectively compared to the sole cropping of corn and mung bean. For this reason, nowadays, many plants, especially legumes, are cultivated in an intercropping form due to their ability to fix nitrogen. Due to the lack of resources regarding the effect of planting direction on plant yield, this study was conducted in order to evaluate resources and soil nutrients by changing the planting direction and replacing the intercropping system of the sunflower with cowpea. Materials and Methods This research was conducted in the field of the Agricultural Research Station of Zabol University during 2015-2016. The experiment was performed as a split-plot based on a randomized complete block design with three replications at the Research Farm of the Agricultural Research Institute of Zabol University. The main factor was two levels of planting direction (North-South and East-West), and the secondary factor was intercropping system in five levels, including (100% pure sunflower), (100% pure cowpea ), (50% sunflower + 50% cowpea ) (25% cowpea + 75% sunflower) and (75 % cowpea + 25%sunflower) were considered. Data for studied traits were measured as follows: radiation, temperature, volumetric humidity, calcium, phosphorus, magnesium, potassium, and the land equality ratio. Statistical analysis including, analysis of variance and mean comparisons (least significant difference (LSD) test at the 5% level), were applied to evaluated traits. Results and Discussion The maximum absorption of photosynthetically active radiation (PAR) was in the east-west cultivation direction (77.90%) compared to the north-south treatment, which was 24.6% more than the north-south direction. The analysis of variance indicated that the cultivation direction and intercropping systems on the amount of phosphorus in the soil after harvest were significant at 1% probability level. The comparison of means treatments showed that the amount of phosphorus in the soil in the direction of east-west cultivation was 15% higher compared to the direction of north-south cultivation. The highest amount of soil potassium was obtained in the east-west treatment and the intercropping system of 50% sunflower plus 50% cowpea (24.7 ppm). The lowest amount of soil potassium (16.15 ppm) was obtained in the treatment of east-west cultivation and the intercropping system of 75% sunflower plus 25% cowpea. The relative advantage of intercropping is expressed by the land equivalent ratio. The increase in the ratio of equal land per unit shows the relative usefulness of intercropping compared to sole cropping of each of the mixed components. The comparison of means of the intercropping system showed that among the treatments, the mixture of 75% sunflower plus 25% cowpea had the highest land equivalent ratio (2.54). Conclusion It seems that in order to maintain humidity make maximum use of limited water resources, and obtain high yield, the intercropping system of 75% sunflower plus 25% cowpea and planting direction the prevailing wind of the region (east-west) should be suitable for this region and regions with similar climate and windy conditions. Acknowledgments We would like to thank the chairman and the respected staff of the Agricultural Research Institute of Zabul University, who sincerely accompanied us in the implementation of this thesis.

1-Introduction Carbon dioxide emissions caused by human activities, industrial activities and other sources are increasing day by day. The increase of this gas as an important greenhouse gas can cause fundamental changes in global temperature and climate change. Soil respiration is one of the main natural ways of releasing carbon dioxide into the atmosphere in terrestrial ecosystems, and by studying it, one can gain a lot of knowledge about the global carbon cycle. Tree species can influence soil microbial respiration by affecting biogeochemical processes through the amount of litterfall. On the other hand, the different directions of the trees, due to the changes in the radiation angle, which affects the amount of moisture and temperature, probably cause different responses of soil microbial respiration. 2-Methodology In this research, spatial changes of soil microbial respiration by integrating geographical aspects (north, west, east, south) and five different distances (0.5, 1, 1.5, 2 and 2.5 meters) from the tree trunk for the study of soil microbial respiration in three different oak species (Quercus infectoria Oliv., Quercus brantii Lindl. and Quercus libani Oliv.) were carried out in Baneh, Armardeh forests. Three oak trees were selected in the types with the dominant percentage of the desired species (almost identical in terms of height, diameter at breast and canopy). Soil microbial respiration was recorded using Anderson method and moisture in the laboratory and the temperature of the soil were also recorded at the same time sampling at the sample site (soil samples were taken from a depth of 0-10 cm). One-way analysis of variance and Tukey's test were used to check the significance of the difference in the measured characteristics between different oak species. 3-Results: The results showed that there was no significant difference in the parameters of microbial respiration and moisture between the different aspects of each of the different oak species. The results of soil temperature also showed a significant difference in Quercus brantii species between different aspects, and no significant difference was observed in Quercus infectoria and Quercus libani species. On the other hand, there were significant differences between different distances from the trunk. Also, the results of comparing the average soil microbial respiration between different species were not significant, but the results of comparing the average between different oak species at different distances showed differences between the three species. The main environmental factors in this study included soil temperature and soil moisture, which were significantly affected by spatial heterogeneity. The average soil temperature related to Quercus brantii species had a significant difference in different aspects, which could be due to the difference in the intensity of lighting during the day and the aspects of the sunlight and the change of shade over time. There was a difference in soil temperature at different distances in all three species, and this could be due to the low canopy density of the Zagros forests. 4-Discussion & Conclusions Single trees affect the substrates on which they grow and may leave their traces on the soil through the influence of the canopy and roots. The "single-tree influence" concept envisions the soil landscape as a mosaic of small patches that are spatially and genetically linked to individual trees. There are two aspects to this concept: first, within the circle of influence of each tree, soil properties vary predictably in relation to distance from the trunk and crown edge, and second, at any location relative to the trunk and crown, the degree of feature development varies as well. Soil properties are different among tree species. In other words, the organic matter produced by any tree species is different and the related grass cover contains different proportions of nutrients, lignin and secondary metabolites, which determine the quality of organic matter and the rate of decomposition. This study also showed that the spatial heterogeneity in soil temperature and moisture content may be intrinsic mechanisms that drive differences in soil microbial respiration. These findings can deepen our understanding of changes in microbial respiration and soil respiration and clarify the ecological role of different species for us. [ABSTRACT FROM AUTHOR]

Spatiotemporal estimation and monitoring of soil moisture based on remote sensing observations (optical and thermal) is challenging due to its physical nature in high vegetation conditions, necessitating improving and increasing the accuracy of soil moisture estimation in these areas. Therefore, this research aimed to develop a new approach to estimating surface soil moisture in agricultural fields with dense vegetation using machine learning algorithms by incorporating optical and thermal remote sensing data and soil physical properties. For this objective, 16 Landsat-8 satellite images and more than 430 control locations were used during the sugarcane crop’s growth period in 2018-2019 at the Hakim Farabi Sugarcane Agro-Industrial company in the Khuzestan province of Iran. A set of 10 scenarios of various unique combinations of the available input variables were developed and then evaluated by five machine learning algorithms, including multiple linear regression (MLR), decision tree-based algorithms (CART and M5P), and ensemble learning-based algorithms (gradient-boosted regression trees (GBRT) and random forest regression (RFR)). According to the results, the highest correlation between input variables and surface soil moisture was observed in Soil Wetness Index (SWI) and Normalized Soil Moisture Index (NSMI) with R values of 0.79 and 0.69, respectively. Also, the highest accuracy of machine learning algorithms based on R2, RMSE, and MAE results was obtained in GBRT (0.99, 0.011, and 0.006) and RFR (0.99, 0.014, and 0.007), respectively. In general, the findings of this research show the importance of using variables based on Landsat-8 remote sensing data in combination with ensemble learning algorithms that can be independent of any ground measurements. [ABSTRACT FROM AUTHOR]

The global demand for food can be eliminated by precision farming. This research work proposes a low-cost IoT-enabled handy device to measure soil water content. Three different sensor probes are designed in COMSOL Multiphysics 5.4 and fabricated using PCB Technology. The designed sensor probes are calibrated to effectively measure moisture content for three different soil types (silt/sandy/clay). An electronic system has been programmed according to Optimized-Moisture-Value (OMV) algorithm to read and collect the soil moisture information. Three sensor probes, capacitance, and voltage responses are analyzed using linear fitting. It has been observed from the response data that model B's performance is better than the other two presented models in terms of soil moisture. The obtained goodness of fitness value for model B is around 0.999 for all the categories of soils. The electronic system is built around W78E054D and ESP8266 controllers. The W78E054D controller is used to excite the sensor probe with a signal having a frequency of 500 kHz. The IoT-enabled controller ESP8266 reads and collects the soil moisture data according to the OMV algorithm.

Measurement of soil moisture and control of irrigation according to the measured data is crucial in agriculture fields where water scarcity is always a serious issue. For this purpose, a cost-effective distributive network system has been proposed and developed using technology like IoT to control complex irrigation processes. An internet-enabled embedded moisture sensing unit was designed that consists of a capacitive sensor probe and electronic system to process the soil moisture value. The sensor probe was calibrated for six different varieties of soil using the Thermo gravimetric method. The output response is inspiring, with a goodness of fit value of 0.99. Algorithms are developed for irrigation control that operates by a developed web-based application from the control station. The system was implemented at a total cost of 122.37 US dollars and tested in cassava agriculture field for loam soil in Nagaland, India, for 91 days and showed magnificent water saving of up to 95% compared with traditional approaches.

Abstract Introduction: Many factors are involved in agricultural development such as climatic conditions, soil moisture, evapotranspiration and etc. For their effectiveness, it is necessary to examine the key parameters. Timely and accurate monitoring of these committees with the help of satellite imagery is a necessity in this regard. Herat plain is one of the plains where soil salinity and lack of moisture has led to a critical situation of gardens and agricultural lands. Methods: In this research, we have tried to study soil salinity, soil moisture and actual evapotranspiration using the MODIS sensor data for the four months of February, May, August and November 2017. Findings: The first stage of vegetation survey shows 0.4 in May (growing season). While the maximum land surface temperature was recorded in August (54 ° C) and May (45.15 ° C). Then, in the next step, using the results of two indicators of vegetation and land surface temperature, the humidity of the area is investigated by TVDI. The humidity of the region was divided into five classes from zero to 0.5, which indicates the low soil moisture and dryness in the Herat plain. Finally, due to the dryness of the area and to verify the TVDI method, field soil samples were taken from different parts of Herat and especially its agricultural lands to estimate the soil salinity (EC, PH and soil moisture). The results showed that the soil moisture content of the samples at a depth of 5 cm above the ground varies between 0 and 0.3. Also, out of 12 soil samples, 6 samples have saline soils and one sample has saline-acid soils. Of course, it is also important to note that some of the agricultural lands whose soils are in the saline group are dry and left to their own devices. Finally, the study of actual evapotranspiration with the SEBAL algorithm showed that in this region, despite the lack of moisture, actual evapotranspiration is very high, especially in the hot month of August.

Background and objectives: Grasses are important forage crops, which are used for forage production, pasture establishment, rangeland renovation, and soil conservation. Perennial cold-season grasses have high forage production, are resistant to adverse environmental stress and have broad adaptability in various environments. They are cultivated for various purposes of agriculture and soil protection. The perennial cold-season grasses with relatively deep roots have a long life in suitable conditions. These plants are able to establish and grow with good productivity in poor to moderate soils. The purpose of this research was to identify and select the best genotypes of four perennial cold-season grass species, in terms of physiological response under normal irrigation and drought stress. Methodology: In this research, the best genotypes of each species of desert wheatgrass (Agropyron desertorum), bromegrass (Bromus inermis), cocksfoot (Dactylis glomerata) and tall fescue (Festuca arundinacea) were selected in previous trials for both seed and forage yield. For each species, three genotypes were evaluated in a field experiment under normal irrigation at 100% and 50% field capacity (FC), using a complete randomized block design with three repetitions in Agriculture and Natural Resources Research of East Azerbaijan in 2021. Drought stress was applied and at the vegetative growing stage, some key physiological traits such as cell membrane stability (CMS), protein content, content of pigments (Chlorophyll and carotenoid) and water potential under both drought stress and control were evaluated. Results: The results showed that genotype Fa-G1 in Festuca arundinacea, genotype Bi-G3 in Bromus inermis, genotype Dg-G1 in Dactylis glomerata and genotype Ad-G1 in Agropyron desertorum were more tolerant to drought stress compared to other genotypes within species. Conclusion: The response of plants to drought stress was different depending on the type of plant. It was suggested that the leaf osmotic potential index could be used as one of the most important physiological indicators in drought stress conditions to identify drought-tolerant genotypes. Generally, Agropyron desertorum, Bromus inermis, Festuca arundinacea, and Dactylis glomerata are the most resistant to drought stress. [ABSTRACT FROM AUTHOR]

The extent of the energy received from the sun to the earth is one of the main and important input parameters in the agricultural, ecological, hydrological, climatological, and environmental models. It has also a key role in most processes related to the soil-plant-atmosphere system such as net radiation, reference evapotranspiration, soil temperature, moisture, and snow melt. In this research, the efficiency of three categories of the global radiation empirical models including sunshine-based, air temperature-based, and cloudiness-based models was evaluated during the 1997-2021 period for the Sanandaj synoptic station and after these model's calibration procedure, the better models were recognized. By adopting the estimated global radiation by better models as the input of modeling some processes including net radiation, reference evapotranspiration, soil temperature, and moisture and snow melt, the model outputs were compared with the case that the measured global radiation had been adopted as these models input. After the calibration of global radiation models and optimizing the empirical parameters of them, which were performed based on minimizing the RMSE index between the left and right sides of these equations, finally, three models including Angstrom-PPeesott model, the Bristow-Campbell model, and the Black model were selected as the representative of each of the three mentioned categories. In the next step, cross validation was applied to these three models based on the MAE ،MBE ،R2 and Reff indices. The results showed a reasonable agreement between the measured and estimated global radiation based on all of these three selected models. The MAE index for Angstrom-Prescott, Bristow-Campbell, and Black models was 138.5, 227.14, and 251.3 kj.m-2.day-1, respectively which can be considered as the acceptable extent. The MBE index led to obtaining good results with no considerable bias for Angstrom-Prescott model (-3.9 kj.m-2.day-1) and the Bristow-Campbell model (+11.9 kj.m-2.day-1) but a positive overestimating bias using the Black model (+159 kj.m-2.day-1). For all three models, the R2 and Reff were respectively greater than 0.83 and 0.78 values. The best values of these two indices were obtained for the Angstrom-Prescott model. Regarding comparison of the outcome of estimated and measured global radiation when applying as the input of some models, the histogram of the errors (the difference between outputs of some of the processes models based on the estimated and measured global radiation inputs) for net radiation calculation showed the error range mostly from -50 to +50 kj.m-2.day-1 for all of the three global radiation model inputs, which as seemed to be a narrow difference between these two cases. For reference evapotranspiration calculation, the histogram of errors was mainly between very low values of -0.2 to 0.1 mm.day-1 for all of the three global radiation models. Regarding l temperature modeling, the Angstrom-Prescott model (with error range between -0.5 to 0.2 °C) showed a better performance than the Bristow-Campbell and Black models (with error range between -1 to 1 °C). For soil moisture modeling, the Angstrom-Prescott model showed very suitable performance with the most error values close to zero and the Bristow-Campbell and Black models showed relatively suitable and similar performance. The snow modeling performed based on some few snowy days, the Angstrom-Prescott model with focusing the histogram error between -2 to 0.5 cm can be considered as the best model and the Bristow-Campbell and Black models showed similar but not as good performance. On the whole, the results indicated that the appropriate outcomes were obtained when applying the global radiation estimated by Angstrom-Prescott model as the input of all of the processes models. Regarding Bristow-Campbell and Black methods, which led to obtaining relatively similar results, applying them as the inputs of different models led to a diversity of results including very appropriate (for reference evapotranspiration), appropriate (for net radiation), relatively appropriate (soil temperature and moisture) and not-appropriate (for snow). [ABSTRACT FROM AUTHOR]

Runoff is formed by spending some time after rain and significantly depends on rainfall intensity, soil moisture, and slope. One of the fundamental questions about runoff is the time that it starts to create. In this research, the runoff start time in sandy loam soil was evaluated experimentally under different conditions using a precipitation simulator machine. The rainfall intensity parameters of (60, 80, and 100 millimeters per hour) and the slope of (0 and 5 percent) were investigated. The rainfall was created in the three soil treatment types completely dry (Sdry), the dry soil that had been saturated 24 hours before the test (S24hrlag), and the dry soil that had been saturated 48 hours before the test (S48hrlag). Eighteen tests were conducted on this soil. At the end of each test, the soil moisture was measured. The experimental results were compared with the numerical model of Green-Ampt. According to the Kendall and Spearman correlation test results, as the rainfall be intense, the start time of the runoff is lower. Also, the runoff starts at a faster time in the slope of 5 percent for every three types of soil. Also, the results of starting time of the runoff in the soil with a delay of 48 hours in the rain compared to the soil with a delay of 24 hours in the rain are closer in all of the rainfall intensity and slopes compared to the case of dry soil. Therefore, in the experiments related to a delay of 24 hours, the time of the start of runoff decreases. While in tests with a delay of 48 hours, it was not much different from completely dry soil. Also, the Green-Ampt results are close to the experimental results (R²=0.9775), and the maximum difference between the two mentioned methods is 4.8 minutes. Therefore, it can be used with the Green-Ampt method to calculate the start time of runoff in sandy loam soil in different states of rainfall intensity and bed slope. [ABSTRACT FROM AUTHOR]

The pattern of root distribution in layered soils is one of the significant issues in the calculations of soil water and irrigation management and planning. The objective of this study was to determine the pattern of root distribution of soybean in layered soils and its effect on water uptake. The research was conducted in a completely randomized design with 15 treatments consisting of three different textures of soil (light, heavy, and medium) in four replications. The pattern of root distribution was monitored by the sampling of columns at the end of the growth period of the soybean. It was observed that the presence of the layer with medium texture has led to better plant development and growth after comparing the treatments in terms of plant growth. In general, root length density decreased with increasing soil depth, except in cases where there were different layers of soil, and root length density takes place in the following order: root length density in layers with medium texture≥ heavy texture≥ light texture. The rate of root water uptake rate was highest in the sandy layers, intermediate in clay, and lowest in loamy texture. Also, the rate of root water uptake rate increased significantly with increasing depth regardless of treatments. It can be concluded that the pattern of root distribution and plant growth is significantly affected by soil texture and its stratification. [ABSTRACT FROM AUTHOR]

The Center pivot system is one of the most advanced sprinkler irrigation systems that recently has been used in Iran. According to this research on the compatibility of the system with the cultural, economic, climate and optimization performance of the system is essential. The importance of this matter on one side and the lack of information on the other hand, it highlights the need for an investigation. In this regard, the evaluation of the Center pivot system in two speeds 10 and 60 percent took a radial and vertical. The uniformity coefficient (CU) in the radial arrangement of cans and in two speeds 10 and 60 % was 80.3 and 76.4%, respectively and the uniformity of water distribution (DU) was 72.6 and 65.5 respectively. Also the uniformity coefficient (CU) in the vertical arrangement of cans and in the same speed was 61.1 and 59.3 % respectively. Uniform distribution of moisture in the soil after irrigation with rate of 60% was 86.37 percent. So the amount of Uniform distribution of moisture in the soil was higher than the uniformity coefficient in the Surface Soil (CU). The main reason is the horizontal flow and water transfer in the soil and its influencing factors (Mass flow, Diffusion and Hydrodynamic dispersion). According to this and given the lack of available water resources in arid and semi-arid area, maybe there is no need to increase water of irrigation in order to increase the uniformity of water distribution to more than 70 percent

Background and Objectives: Soil respiration is the emission of carbon dioxide from soil surfaces that controls the primary carbon cycle in ecosystems. Recently, soil respiration has become an important ecological process in the global carbon balance and has an important impact on global climate change. Measuring soil respiration is important for quantifying the flux of CO2 from soils to the atmosphere. In the forests of Iran, no study has been conducted on the process of soil respiration at different times of the day and night, which underlines the innovative aspect of this study. The aim of this study was to compare soil respiration rates at different times of the day between five forest types (Pure Quercus infectoria), (Quercus infectoria-Quercus libani), (Pure Quercus libani), (Quercus libani- Quercus brantii- Quercus infectoria) and (Quercus libani- Quercus infectoria) in the four seasons of the year (i.e., spring, summer, autumn, and winter) and to identify the effect of environmental factors (i.e., temperature and moisture) that cause changes in soil respiration rates using different models. In addition, the correlation between respiration rates and soil chemical properties was analyzed. Materials and Methods: Five dominant forest types were selected and sample plots of 20×20 meters were delineated within each forest type. In order to measure soil respiration, 8 PVC pipes of specific size and diameter were installed at a depth of 5 cm in the selected sample piece and measured using Anderson's method at different times of the day. Soil temperature and soil moisture were measured with a thermometer and a TDR device, respectively, simultaneously with soil respiration measurement. In order to perform chemical tests, 5 soil samples of each type were taken during the growing season and transferred to the laboratory. Results: The greatest amount of soil respiration was observed at 2:00 p.m., the Pure Libani type also showed the highest soil respiration rate with an average of 0.3550 mg carbon cm-1 per day for the whole year, but this value was not statistically significant between different forest types. The highest correlation coefficient between soil respiration rates, temperature and moisture found in the Libani-Infectoria type with a higher value for soil moisture than soil temperature. Spring showed the highest amount of soil respiration due to optimum temperature and moisture. Looking at the fitted models of soil respiration, the exponential model showed a better fit than the linear model to the measured data. Finally, respiration did not show a significant correlation with soil chemical properties. Conclusion: According to the results, in spring and summer, the daily changes in soil respiration in the afternoon were significantly higher than at other times, and the soil respiration was the highest value for the Pure Libani type. Our study also showed that forest species can affect soil phosphorus and pH. The highest correlation coefficient of soil respiration with climatic elements and soil chemical properties was observed with soil moisture and organic nitrogen, respectively. Our findings showed that a combination of soil chemical properties rather than a single factor, together with temperature and moisture factors at different times and seasons, can determine changes in soil respiration. Finally, the effect of different forest types on the soil respiration rate caused slight differences, but it cannot be significant in different oak types of Armardeh forests. Although these findings help to fill out the gaps in the study of soil respiration in different forest types under current climate conditions. The rate of soil respiration in relation to the effect of different species is not yet precisely known. Therefore, further study should focus on factors driving autotrophic respiration and heterotrophic respiration and the response of microorganisms to climate change. [ABSTRACT FROM AUTHOR]

Investigation of homogeneity regions using univariate characteristics is an important step in the regional frequency analysis method. However, some hydrological phenomena have multivariate characteristics that cannot be studied by univariate methods. Droughts are one of these phenomena their definition as univariate will not be effective for risk assessment, decision-making, and management. Therefore, in this study, the regional frequency analysis of drought was studied in multivariate methods using SEI (Standardized Evapotranspiration Index), SSI (Standardized Soil Moisture Index), and SRI (Standardized Runoff Index) indices in the Karkheh River basin from 1996 to 2019. The indices calculated probabilistic distribution between the variables of evapotranspiration, runoff, and soil moisture using multivariate L-moments method and Copula functions and considered meteorological, agricultural, and hydrological droughts simultaneously. The results of multivariate regional frequency analysis considering the Copula Gumbel as the regional Copula showed that the basin is homogeneous in terms of severity of SEI-SSI combined drought indices and is heterogeneous in terms of severity of SEI-SSI combined drought indices. However, after clustering the basin into four homogeneous areas in terms of characteristics of SPI (Standardized Precipitation Index), the basin is homogeneous in all areas in terms of univariate SEI, SSI, and SRI indices and is heterogeneous in the third and fourth clusters of SRI and SSI drought indices. Pearson Type (III), Pareto, normal, and general logistics distribution functions were found suitable to investigate the characteristics of SEI, SSI, and SRI drought indices in this case. Finally, large estimates of the types of combined droughts and their probability of occurrence showed that the northern and southern parts of the Karkheh River basin will experience short and consecutive droughts in the next years. Droughts in areas without meteorological data can be predicted in terms of joint probability using the multivariate regional frequency analysis method proposed in this study. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effect of different levels of drip irrigation treatment on yield, yield components and quality of green tea leaves during drought. This research was conducted for the first time during 2017 and 2018 in the tea garden in Bazkiagorab area of ​​Lahijan in Gilan province. The experiment was performed as split plots in a randomized complete block design with three replications. Irrigation treatment considered was consisted of five levels of 0, 25, 50, 75 and 100% of irrigation needs. Drip irrigation program in the period of water stress was carried out twice a week based on monitoring soil moisture at the depth of root development. Full irrigation of 2225 and 1610 m3/ha in two successive years of experiment caused the production of harvestable shoots in summer to increase by 162 and 153%, respectively, compared with the area without irrigation. Increased water stress at incomplete irrigation levels led to an increase in solids (woodiness) of tea shoots. Conversely, as the amount of irrigation water in the drip irrigation system increased, the weight of the shoots increased. The biennial average of the highest yield of green tea leaves was equal to 9125 kg/ha with 100% irrigation requirement and the lowest yield of 3468 kg/ha was obtained from the area without irrigation. Improvement of tea quality characteristics such as total polyphenols, caffeine, total ash and nitrogen percentage of shoots was also observed by complete irrigation in the drip system.

Wild cherry (Prunus avium) is one of the native and fast-growing broadleaves species of the Hyrcanian forests that can be used in mixed reforestations. Therefore, knowledge of the survival reaction and some morphological and physiological characteristics of seedlings of this species at different levels of soil moisture content (SMC) is crucial for the development of seedling production and afforestation programs, as well as habitat restoration. This experiment was conducted in a completely randomized block design with four irrigation levels (control or 100%, 75%, 50% and 25% of field capacity) in 3 replications and 5 seedlings per replication as subsamples. Thus, the seedlings were examined for five months (May to September) and a total of 60 potted seedlings were tested and sampled. Morphological characteristics of seedlings such as survival, height growth, diameter growth, root dry weight, stem dry weight, total dry weight, and root to stem ratio and physiological characteristics of plant pigment concentrations including chlorophyll (a, b and total), carotenoids, soluble sugars and proline were measured. The results showed that reducing SMC had different effects on morphological and physiological traits of wild cherry seedlings. With decreasing SMC, the amount of chlorophylls a and b, total chlorophyll, decreased. Proline levels were quadrupled and soluble sugars were doubled when extreme humidity decreased. An increase in the amount of proline and soluble sugars makes the plant more tolerant of drought. Therefore, at least 50% of the field moisture capacity in the rooting environment of seedlings is necessary.

The southern regions of Kerman Province have repeatedly encountered dust storms. Therefore, the objective of this study was to identify dust sources using effective parameters such as vegetation cover, land surface temperature, soil moisture, soil texture, and slope as well as to detect dust storms originating from these regions based on 31 MODIS images in 2016 and SRTM data. After normalizing parameters, the dust source map was prepared by fuzzy logic and assessed with an error matrix and available dust source map. Results showed that 30.5% of the study area was classified as a low source of dust, 39.55% as moderate, and 29.85% as severe-very severe. The overall accuracy of the produced map was about 70% and the producer and user accuracy of the severe-very severe class was more than 87%. The detection of dust storms originated from the identified dust sources also confirmed a crisis situation in the region. Due to the repeatability and continuity of obtained dust source map at pixel scale, it can be used to update available dust source maps and manage dust crisis in the region, properly.

In literary and artistic works, imagination plays an essential role. The existence of different definitions of this term each explains different aspects of the word. In fact, imagination is a defense mechanism so that the poet and writer can overcome their inner inflammations and anxieties. One of the reasons for paying attention to imagination and imaginative structures is to explain the thoughts and feelings of poets and writers. The presence of bold symbols with positive valuation makes it possible to study Sana'i lyric poems according to Gilbert Durand's theory. The abundance of symbols related to his poems confirms the poet's ability to overcome internal worries and turmoil. In Sanai lyric poems, unpleasant symbols, along with the use of pleasant symbols, and the poet's desire to use safety symbols are combined to present a desirable image of the beloved and to express the poet's psychological characteristics. Introversion, self-knowledge, positivism, and adaptation to adversity are revealed in the shadow of the poet's attention to the symbols of introversion. The motherly symbols of the "beloved's threshold" and "the vessel and its contents" express humility, the lover's desire for peace, and the beloved bow. Disrupting the natural order of cycles, passionate descriptions of the future and the past, along with contradictory descriptions, are other ways in which the poet escapes time to show the evolution of the beloved and the steadfastness of the lover. Poets like Sanai, who tend to use the symbols of the nocturnal system, especially the soothing symbols of water and soil, are usually positive-minded, peaceful, moderate, adaptable, and so sad. They solve problems with a peaceful gesture. In each of the works, depending on the tendency and frequency of the symbols of this theory, new aspects of the imagination, and psychological and intellectual characteristics of the poet or writer can be achieved. [ABSTRACT FROM AUTHOR]

Several indices are used for drought identification and quantification. In this paper, the new Standardized Palmer Drought index (SPDI) was introduced and then the drought condition of Chaharmahal-Va-Bakhtiari Province was studied using this index. For this study, 11 synoptic, climatology, and evaporation meteorology stations were selected. Essential information in this investigation includes monthly temperature, monthly precipitation, and soil moisture measurement. To estimate SPDI, moisture departure, was first calculated on a monthly time scale. Then, converted to cumulative moisture departure values in different time scales including 3, 6, 9, 12, and 24 months. The best statistical distribution (GEV) was then fitted to cumulative departure. These values were then standardized to have the SPDI. The results showed that, as soil moisture affects SPDI estimation, it will be more valid for analyzing and monitoring drought conditions, especially for agricultural drought. Also, the results showed that 2000, 2001, and 2008 years were the driest time in this Province from 1988 to 2012. Moreover, drought frequency was found out in the western half of the Province more than in the other parts.

This study was conducted to evaluate the effect of polymer mulches and plant mulch on some soil physical properties. For this purpose, effects of synthetic polymer (acrylic resin), natural polymer (modified cellulose), natural - synthetic polymer (modified cellulose / acrylic resin), and litter, On some physical properties of soil at two depths (0-5 cm and 5-30 cm) and two time periods (one week and six months after applying mulches) in a completely randomized design with four replications was studied. 10*10 meter experimental plots were considered and mulches covered 2 cm of the soil surface in each plot. The results showed that the use of mulches in the first week of applying, affected the bulk density (3.6% increase in synthetic polymer), porosity (6.01% increase in synthetic polymer), temperature (2.52% increase in litter and 1.85 decrease in natural polymer) and humidity (16.67% increase in synthetic polymer) at the layer of 0-5 cm, Soil moisture (16.67% increase in synthetic polymer) was also affected at the depth of 5-30 cm. Six months after the experiment began, mulches were applied, made a significant difference compared to control in the bulk density (4.81% and 2.12% decrease in synthetic polymer for 1st and 2nd layers respectively), porosity (8.23% increase in synthetic polymer for 1st layer and 4.12% increase in natural - synthetic polymer for 2nd layer) and moisture content of both surface and beneath soil (103.53% and 48.6% increase in natural - synthetic polymer for 1st and 2nd layers respectively), also the electrical conductivity of the first depth of soil (6.23% decrease in natural - synthetic polymer) was affected. [ABSTRACT FROM AUTHOR]

Wind erosion is one of the most important natural processes in arid and semi-arid regions. Sistan plain has a hyper-arid climate and is one of the windy regions of the country. Due to the soil characteristics of the Sistan plain, wind erosion is very intense in this region. In this study, the relationships between some soil's physical and chemical properties and wind erosion were investigated in different land cover in a part of the central region of Sistan in 2018. A map of land cover in five classes was prepared using the results of field studies and the classification of satellite images. Fifty soil samples at a depth of 10 cm were collected to investigate the physical and chemical soil properties and the wind erosion threshold was determined at each location using a portable wind tunnel device. Also, the relationship between physical and chemical soil properties including soil texture, soil moisture, specific apparent weight, EC, SAR, ESP, Na+, k+, with the speed of wind erosion threshold was investigated. According to the results, the highest and the lowest threshold speed were 8.2 and 3.8 m s-1 and occurred in agricultural lands and hilly lands, respectively. The results of this study indicated that the velocity of wind erosion threshold in different lands adjacent to sandy areas is less than the average of that cover. Also, the soil texture, EC, and SAR have the most significant effect on soil wind erodibility at P <0.05 in the study area. [ABSTRACT FROM AUTHOR]

Introduction Mulberry is one of the plants that are compatible with dry areas. A little research has been done on the irrigation of mulberry seedlings using different methods in arid and special areas of Sistan. In the past, there were suitable climatic conditions for the establishment of mulberry trees in Sistan. If mulberry orchards are revived in the area, in addition to fruit production and the prosperity of the breeding industry, it will also play an effective role in controlling erosion and improving the environment. Due to the harmful effects of water shortage and lack of proper efficient methods used in the agricultural sector of the country, it is necessary to study and use new methods. This research examines the establishment of fruitful mulberry seedlings with three methods of subsurface irrigation, pottery, and drip irrigation in the Helmand watershed. By establishing vegetation while saving limited water consumption in the region, along with its economic aspects for the stakeholders, should also be effective as windbreaks and improvement of the environment for the development of the region.Materials and MethodsThis research was carried out to evaluate the Mulberry growth using three methods including subsurface irrigation, clay pot, and drop irrigation in dryland regions. Therefore, after preparing hold digs, three soil samples has collected from depth 50 cm of each treatment, and soil characteristics were analyzed. Six-month-old mulberry seedlings were planted in the pits. This research was randomly tested the clay pot irrigation, drop and surface irrigation on mulberry with three treatments and four iterations. Tree high, branch number, diameter, and canopy have been measured. Also, soil moisture was measured at a depth of 60 cm before irrigation. The data were analyzed using SPSS software.Results and Discussion According to the climatic conditions of the region, a total of 700 L of water was given to each seedling. The average moisture content of subsurface irrigation treatment was higher than other treatments. Moisture content in subsurface irrigation, pottery, and surface drops were 18, 14.25, and 13.4%, respectively. The moisture content of subsurface irrigation treatment was 20.8% and 25.5% higher than the moisture content of clay irrigation treatment and drip type, respectively. The mean values have been compared based on the Duncan test and showed the amount of moisture in subsurface irrigation classified in one group and in clay type and surface drops in another group. Statistical analysis showed that there was a significant difference between the moisture content of the three treatments (α< 0.01). Also, significant differences were observed between the mean of plants height of the subsurface (78.5 cm), clay pot (45.5 cm), and drop (59.7 cm) irrigation methods. But, there was no significant difference between canopy, diameter, and branch number. The plant water needs are better provided in the surface irrigation method, and more water is available compared with clay pot and drop irrigation.Conclusion The results of this experiment showed that the subsurface irrigation treatment had a better condition in all characteristics than the pottery and drip irrigation methods. Because it provides more moisture to the plant. This situation is due to the lack of high evaporation in subsurface irrigation, water enters the root zone directly through gravity. Therefore, it is concluded that the subsurface irrigation method is more suitable for plant growth than pottery and drip irrigation which reduces the water loss from the soil surface and better moisture distribution.

Haloxylonplanting and developing artificial forests in arid lands is one of the important actions to combat desertification. In this research, tree planting (by Haloxylon aphyllum Iljin) in Dosangi Meybod in different methods including repairing, runoff control, pitting and planting in owed have been compared with control area. For this purpose, in each area, four 300 m transects were considered randomly - systematically, and 15 plots (10 m2) were randomly collected on each transect. In each plot, vegetation characteristics including total vegetation percentage, density, canopy cover, freshness and depth of root and soil characteristics including moisture, permeability and soil carbon storage were measured. The Shapiro-Wilk test were used to test of normality of the collected data, and were analyzed using one-way analysis of variance and Duncan's test. According to the results of analysis of variance, the effect of planting with different methods on crown cover, density, freshness and deep rooting of Haloxylon shrubs and the percentage of vegetation is significant at 1% level. However, its effect on permeability and soil moisture in May is significant at 1% level and on carbon storage is significant at 5% level. Increase of vegetation cover by 5.1%, density of 249.7 number per hectare, Haloxylon cover of 3.7%, freshness class 1.5, soil moisture in spring 38.1% rooting more than 3 m and permeability 8.03 cm/h was related to the planting in dry river, which had a relative success in vegetation development in this region.

The purpose of this study was to investigate some environmental factors of Zagros forest dieback. In this regard, raster layers of elevation, slope, aspect, hillshade, toposhape and the land formation of Zagros forests in Ilam province were prepared. The distribution map of live and dieback forest cover were also prepared, using Landsat 8 panchromatic images. Then, the percentage of dieback forest cover in each specific class of the studied factors was calculated, using geographic information system (GIS). Results showed that 2.37% of the forest cover area is dieback canopy. The difference in the percentage of dieback forest cover between landforms was negligible. Maximum and minimum dieback areas of forest cover were in southern aspects (2.7%) and northern aspects (1.73%), slope class 0%-20% (2.6%) and more than 80% (1.52%), elevation less than 1300 m (3.36%) and more than 1700 m (0.52%), hillshade class 0-102 (2.56%) and 255-204 (0.82%), Gachsaran formation (5.08%) and Asmari-Shahbazan formation (0.96%), respectively. As a result, the amount of dieback in the southern slopes was 35.9% higher than the northern, in low hillshade was 68% more than high hillshade and in low elevations was 84.5% higher than high elevations. It seems that the higher ratio of crown dieback was occurred in the less hillshade and at low elevations, due to higher temperatures and lower soil moisture in these areas, which indicates the effective role of recent droughts in intensifying the process of forest dieback. [ABSTRACT FROM AUTHOR]

Surface soil moisture retrieval using microwave remote sensing, as the most promising method, has been highly valued due to its great accuracy and temporal resolution in broad scales. However, its coarse resolution limits regional scale applications. This study aims to apply the optional downscaling algorithm to generate high resolution soil moisture (θf) over Firoozabad Watershed, Ardabil, Iran. The algorithm integrates the advantage of Sentinel-1 (S-1) radar and the SMAP Radiometer soil moisture to make a linear correlation between the satellite soil moisture (θc) and the radar backscatter (σo) at each coarse pixel. The outputs were compared with the soil moisture measurements collected from individual points in the study area. The values of 0.043 cm3/cm3 and 0.039 cm3/cm3, respectively, were obtained for RMSE and UnbRMSE at 1 km resolution. This result are close to the SMAP’s downscaled target accuracy (RMSE = 0.05, cm3/cm3). Taken together, point measurement has limitations in terms of spatial representation and spatial extent, especially in a watershed scale data analysis; therefore, utilizing the freely available SMAP soil moisture data and its downscaled version with the S-1 SAR data could be considered as an efficient and low cost tool to be used in research and implementation for the local and regional applications.

The effective use of rainwater is a key issue in agricultural development in arid and semi-arid regions. The tillage system as an important soil management measure can affect the rainwater retention, soil moisture content, and in consequence crop yield in rainfed lands. This study was conducted to evaluate the effects of slope gradient and tillage direction on rainwater use efficiency (RWUE) in rainfed lands in Zanjan Province. The field experiment was performed in five slope gradients (12.6, 15.3, 17, 19.4, and 22%) and two tillage directions (along slope and on contour tillage) at two replications. Mass soil water content was determined at 5-day intervals and runoff was measured after rainfalls. Wheat grain yield was determined for each plot and RWUE was computed using the proportion of wheat grain yield and precipitation. Base on the results, runoff, soil moisture, wheat grain yield, and RWUE were affected by tillage directions, so that runoff in contour line tillage decreased about 6.4 times compared to along slope tillage and in consequence increased soil moisture, wheat grain yield, and RWUE about 8.7, 24.8, and 24.8%, respectively. Increasing runoff production in contour line tillage at steeper slopes was associated with a lower capacity of cultivated furrows that strongly declined soil water retention and negatively affected wheat grain yield and RWUE in the lands. This study revealed that the efficiency of the contour tillage in water retention and RWUE decreases in steeper slopes in rainfed lands. [ABSTRACT FROM AUTHOR]

Iran is located in the dry belt of the earth and is predicted to face water stress in the next half-century. Currently, the area of sugarcane cultivation in Khuzestan is over 85,000 hectares and due to the high water needs of sugarcane and drought conditions, optimization of water consumption and irrigation management is necessary to continue production. Therefore, in this study, the values of soil moisture, canopy cover, biomass yield in five treatments and irrigation levels (start of irrigation at 40%, 50%, 60%, 70%, and 80% soil moisture discharge) during 2 planting dates in the crop year 2015-2016 on sugarcane cultivar CP69-1062 in Amirkabir sugarcane cultivation and industry located in the south of Khuzestan was simulated by AquaCrop model. The measured data on the first culture date (D1) and the second culture date (D2) were used to calibrate and validate the model. The results of NRMSE statistics in canopy cover simulation in calibration and validation sets with values of 2.1 to 15.6% and 3.8 to 18.3%, respectively, and in biomass simulation with values of 6.2 to 15.2%, and 9.5 to 12.6%, respectively and coefficient of determination (R2), range 0.98 to 0.99 indicated that the high ability of the AquaCrop model in simulation canopy cover and biomass yield. whereas, the values of NRMSE of soil depth moisture in the calibration and validation sets ranged from 11.6 to 23.8, and 12.2 to 22.7, respectively, with a coefficient of determination (R2), 0.73 to 0.96 (calibration) 0.8 to 0.93 (validation) showed less accuracy of the model in the simulation. The best scenario is related to the third proposal that water consumption, water use efficiency, and yield are 1710 mm, 1.53, and 42.27 tons per hectare, respectively, which shows a reduction in water consumption of 360 mm. [ABSTRACT FROM AUTHOR]

Soil salinization is a phenomenon that threatens agricultural lands and natural areas, leading to reduced productivity, declinations of soil resources and vegetation covers, and finally, the abandonment of these areas. This study has quantified the groundwater Capillary Rise (CR) and actual Evapotranspiration (ETa) and their relationship with the soil salinity of Azadegan plain, west of Khuzestan Province. The study area has an arid climate, characterized by shallow and saline water table and a high potential evaporation rate. For this purpose, field samplings were carried out in four consecutive seasons of the year to measure salinity, soil moisture, and texture, groundwater table, and salinity at 27 scattered representative points of the study area. The CR values were estimated in different seasons of the year using UPFLOW model. Moreover, four representative Landsat satellite images were acquired to map seasonal changes of ETa through the SEBAL algorithm. Then, the effects of ETa on CR and consequent soil salinity build up were quantified in a seasonal time scale. The results showed that the average daily ETa of Azadegan plain varied from 1.55 to 7.96 mm day-1 in different seasons which caused a capillary rise of around 1.2 to 1.5 mm.day-1 . This has led to the upward movement of 12 to 18.8 ton ha-1 month-1 of salts from shallow groundwater to the soil surface, which has caused surface soil salinization. Also, there was a close relationship between ETa, CR, and soil salinity parameters, which can provide insight into modeling of spatial and temporal changes of soil salinity and provision of solutions to reduce the accumulation of solutes in the soils of the study area. [ABSTRACT FROM AUTHOR]

The southern regions of Kerman Province have repeatedly encountered dust storms. Therefore, the objective of this study was to identify dust sources using effective parameters such as vegetation cover, land surface temperature, soil moisture, soil texture, and slope as well as to detect dust storms originating from these regions based on 31 MODIS images in 2016 and SRTM data. After normalizing parameters, the dust source map was prepared by fuzzy logic and assessed with an error matrix and available dust source map. Results showed that 30.5% of the study area was classified as a low source of dust, 39.55% as moderate, and 29.85% as severe-very severe. The overall accuracy of the produced map was about 70% and the producer and user accuracy of the severe-very severe class was more than 87%. The detection of dust storms originated from the identified dust sources also confirmed a crisis situation in the region. Due to the repeatability and continuity of obtained dust source map at pixel scale, it can be used to update available dust source maps and manage dust crisis in the region, properly. [ABSTRACT FROM AUTHOR]

Soil loss can cause many intra-regional and extra-regional problems, on the other hand, the effect of soil moisture on processes of soil loss and sediment yield for the identification and simulation of soil hydrological response is necessary. Therefore, the application of soil conditioners is essential for soil and water conservation. The present study was conducted to investigate the effect of soil conditioners of vermicompost and nano-manure on variables of soil loss and sediment concentration at moistures of airdried, 15 and 30%, and rainfall intensities of 50 and 90 mm h-1 . The obtained results in addition to confirmation of the significant effect of each conservation treatment at the level of 99 percent on the intended components showed that the conservation treatment of vermicompost compared to nano-manure treatment had more effect on measured variables. Also, the conservation treatment of vermicompost could decrease the soil loss at soil moisture air-dried, 15, and 30 percent with rates of 72.15, 66.63, and 78.76 percent (50 mm h-1 ), respectively, and 45.01, 35.57, and 10.45 percent (of 90 mm h-1 ), respectively. The effect of conservation treatments, soil moistures, and rainfall intensity and the interaction effects of conservation treatments × rainfall intensity and rainfall intensity × soil moisture on changes of soil loss and sediment concentration were significant at the level of 99 percent. The application of vermicompost and nano-manure had acceptable results on studied parameters but the vermicompost effect was more than nanomanure. Therefore, due to the widespread use of different types of conditioners, nowadays, it is needed to move the application feasibility of conditioners such as vermicompost and nano-manure that these have not the adverse effects of environmental. [ABSTRACT FROM AUTHOR]

Soil moisture controls many processes in the climate and is considered as a very important variable in the ecosystem and a basic parameter of the environment. It directly influences the life of plants, animals and microorganisms and plays a major role in the energy exchange between air and soil. The purpose of this study is to estimate the surface moisture of soil using the temperature indicators of the earth surface and the inertia of apparent heat. Therefore, MODIS images were used in Mortazie area of Yazd province in two different time periods, one from Feb, 8, 2018 to Feb, 14, 2018 and the other in the summer from July, 4, 2018 to July, 9, 2018. Also, the temperature-vegetation drought index, mostly used in previous research on soil moisture was applied to evaluates results. The apparent thermal inertia was obtained from images of morning and evening modes from Terra and Aqua satellites. A linear relationship was established between the temperature-vegetation drought index and the apparent heat inertia on specific days. The RMSE and R2 were found to be 0.15 and 0.86 on July, 7, 2018 and 0.18 and 0.76 on Feb, 9, 2018 respectively. The overall results showed a linear and direct relationship between the apparent thermal inertia and the TVDI surface moisture index.

Introduction Soil is one of the most important components of production, food security, self-sufficiency and national economy. Soil of semi-arid regions, which most of Iran's agricultural lands are located in these areas, are poor in terms of organic matter. The soil tillage operations are carried out by means of moldboard plow and removal of plant residue in most of the agricultural systems. This operation, called conventional tillage, requires not only high energy but also damages to soil physical properties and erosion in the long-term. Conventional tillage does not provide good environmental conditions to maintain moisture in the soil due to the impossibility of managing plant residue in the soil surface. In addition this tillage increases the evaporation and losses of soil water content and reduces the soil organic carbon as a result conventional tillage reduces the physical, chemical and biological characteristics of the soil. The objective of this study was investigation of effect of conventional and reduced tillage systems and management of tomato residue on soil water content, yield and yield components of wheat. Materials and Methods The experiment was conducted as split plot based on randomized complete block design with three replications at the Agricultural Research Station, Ferdowsi University of Mashhad, during growth season 2017-18. Tillage system (in two levels i.e. conventional and minimum tillage) and tomato residue retention (0, 30 and 60%) were in main plots and sub plots, respectively. The sowing date was 11th November in 2017.Sampling was done at harvest time and included plant height, spike number.m-2, spike length, grain number per spike, 1000 grain weight, grain yield, biological yield and harvest index. During the growing season, soil water content in 0-20 and 20-40 cm depth was measured by the soil moisture meter (PMS-714 model) two days after irrigation. Data were analyzed with R software; obtained averages compared with Duncan’s multiple range test at the 5% probability level. Results and Discussion The results showed that the effect of tillage system was significant on soil water content in 0-20 cm depth two days after forth irrigation, soil water content in 20-40 cm two days after fifth, sixth and seventh irrigation, spike number.m-2, grain number per spike, grain and biological yield. Maximum of this traits were obtained in reduced tillage due to increased soil nutrition, improved physical condition of the soil and soil water status. However, the effect of management of tomato residue on any of the studied traits was not significant. This could be due to reducing microbial activity, in complete decomposition of plant residues and reducing available nitrogen. The interaction effect between tillage system and tomato residue was significant on soil water content in 0-20 and 20-40 cm depth two days after forth and third irrigation, respectively, grain number per spike, 1000 grain weight and grain yield. Reduced tillage and 60% of tomato residue showed that maximum of soil water content and 1000 grain weight (38.4 g).Maximum of grain number per spike (61.9) and grain yield (7120. 7 kg.ha-1) were obtained in treatment of reduced tillage and 30% of tomato residue. Conclusions The results of this study indicate that in order to achieve maximum grain yield and less damage to the physical and chemical properties of soil, the implementation of reduced tillage and maintenance of 30% of tomato residue is recommended in the studied area. In general, due to climate change and water resource constraints in the country, conservation tillage and residue management practices are a good way to maintain resources and sustainability.

Soil moisture is one of the most important factors that can affect productivity in ecosystems in arid and semiarid regions. The aim of this study was to investigate soil moisture and vegetation changes in the Isfahan province at the seasonal scale. For this purpose, MODIS Land Surface Temperature (LST) and NDVI data were used to calculate the TVDI index, and the rate of soil moisture content was also measured at several soil depths including 5, 10, 20, 30 cm. in the growing season. Seasonal changes of LST and NDVI indices were also studied in different climate regions ranging from humid to hyperarid. The results showed that the changes in NDVI and LST in this region were different, depending on the climate type and soil conditions; the LST and its changes mostly depended on the amount of vegetation cover NDVI changes based on the plant phenology in humid regions, which was were greater than that in arid and semi-arid climates. Soil moisture monitoring indicated that the relationships between TDVI and different soil depths varied based on the seasonal conditions. In the early growing season, the soil moisture at the depth of 0-5 cm had a higher correlation with TVDI, but in the middle of growing season, the deeper soil moisture (10-30 cm) showed the highest correlation. Therefore, the findings of this research indicated the importance of the growing season, soil conditions and vegetation percentage and types in the soil moisture studies by using satellite data.

Several indices are used for drought identification and quantification. In this paper, the new Standardized Palmer Drought index (SPDI) was introduced and then the drought condition of Chaharmahal-Va-Bakhtiari Province was studied using this index. For this study, 11 synoptic, climatology, and evaporation meteorology stations were selected. Essential information in this investigation includes monthly temperature, monthly precipitation, and soil moisture measurement. To estimate SPDI, moisture departure, was first calculated on a monthly time scale. Then, converted to cumulative moisture departure values in different time scales including 3, 6, 9, 12, and 24 months. The best statistical distribution (GEV) was then fitted to cumulative departure. These values were then standardized to have the SPDI. The results showed that, as soil moisture affects SPDI estimation, it will be more valid for analyzing and monitoring drought conditions, especially for agricultural drought. Also, the results showed that 2000, 2001, and 2008 years were the driest time in this Province from 1988 to 2012. Moreover, drought frequency was found out in the western half of the Province more than in the other parts. [ABSTRACT FROM AUTHOR]

As the population grows and people's living standards rise, the global demand for freshwater is constantly increasing. Agriculture is not only the largest consumer of water in the world, but also one of the cheapest and least efficient consumers with the highest subsidy rates. Nowadays, optimal management of irrigation water is very essential issue and valuable tools calls irrigation management models to improve for this optimizing and Facilitating. For this purpose, the two-year 2004-2005 & 2005-2006 experiment to determine the accuracy of the simulation AquaCrop model calibration and AquaCrop indices barley crop was in Darab-IRAN. Many countries, especially those located in arid and semi-arid areas, need water to produce agricultural products, and many of our country's crops and gardens are also cultivated in the water.