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Snowfall/cover and snowmelt are essential determinants of winter soil processes/events that may force the biogeochemical dynamics of soils in temperate regions. Increasing variability of the European hydroclimate is expected to lead to more frequent intermittent warm periods, which cause snowmelt during winter and rapidly mobilize large amounts of dissolved organic matter (DOM). This study, conducted at the Hainich Critical Zone Exploratory in Germany, seeks to address a significant gap in understanding the molecular impacts of snowmelt-induced DOM flows and their ability to alter soil ecosystems rapidly. During two snowmelt events between January and March 2021, we observed that DOM concentration and composition varied more in forest soil seepage than in grassland soil seepage. Forest seepage showed a pronounced DOM flux peak and synchronous increases in the relative abundances of aromatic DOM components, indicating surface-derived transport of plant litter carbon. In the grassland, however, peak DOM fluxes were characterized by a marked increase in nitrogen-containing (N-containing) DOM components, indicating a predominance of microbial carbon. Notably, the unique DOM components specific to each ecosystem increased during peak fluxes in the forest but decreased in the grassland. We suggest that an overall higher molecular richness and the broader functional metabolic potentials in grassland may account for its relatively greater DOM stability compared to the forest during peak snowmelt events. [ABSTRACT FROM AUTHOR]

The primary objective of this study is to evaluate soil evaporation in arid regions using a minimal set of readily accessible parameters, which are represented through a nomogram. This work explores the relationships between soil evaporation, soil water deficit, and air temperature. Evaporation is a critical factor influencing the soil water regime. Irrigation artificially adjusts soil moisture to maintain it within optimal limits for vegetation. This regulation can only be effectively managed if the principles of soil-water balance are thoroughly understood. In arid and semi-arid regions, where water quality is often poor (high salinity), prolonged excessive irrigation can lead to soil salinization, thereby reducing agricultural productivity. In this study, ten lysimeters were used to measure soil evaporation at different levels of soil water saturation. The highest evaporation rate was recorded in fully saturated soil, peaking at 548 mm. This rate decreased as the soil water saturation decreased. Therefore, a good knowledge of the evaporation value is necessary to establish appropriate irrigation and soil leaching rates and consequently, an adequate water balance. [ABSTRACT FROM AUTHOR]

Lysimeters have been used to obtain accurate information for developing calibrating, and validating crop evapotranspiration and crop coefficients for many plants and crops. Lysimeters are also an unique equipment for studying the transport of solutes when saline waters are used, and therefore, for assessing alkalization and salinization hazards. Three main types of lysimeters are used: constatnt water-table lysimeters, drainage lysimeters, and weighing lysimeters. The weighing lysimeters provide scientist the basic information for research related to the evapotranspiration, and they are commonly divided into two types, continuous weighing and intermittent weighing. Lysimeters are foremost devices, typically tanks or containers, that define a specific boundary to contain soil water and permit measurement of either the soil-water balance or the volume of water percolating vertically and its quality. The limitations are expense which depends on design, variable experimental conditions such as climatic/environmental factors which are usually not controlled, the spatial variability is normally less, they are not appropriate for every plant species and even every soil type. The main goal of lysimeter is defining the crop coefficient (Kc) which used to convert Etr to equivalent crop ET (Etc) values, and determining agronomical parameters of crops which are planted on the field of lysimeter. All weather data like air temperature, humidity, solar radiation, and potential evaporation should be obtained onsite, and the frequency and time of measurements should be at least daily. For crop products, the management such as fertilization, sowing tillage, seed bed preparation, and harvest of the lysimeter including its surrounding area is carried out on the basis of good agricultural practice. it may be required to complement natural precipitation by irrigation. The main purpose of this literature review is to give a brief summary about lysimeters, and survey the impacts of lysimeter studies and crops production. The information provides is obtained from randomized control experiments, review articles, and analytical studies and observations which were gathered from numerous literature sources such as Scopus, PubMed, Google Scholar,and Science Direct.

Evapotranspiration plays a key role in the terrestrial water cycle, climate extremes, and vegetation functioning. However, the understanding of spatio-temporal variability of evapotranspiration is limited by a lack of measurement techniques that are low cost and that can be applied anywhere at any time. Here we investigate the estimation of evapotranspiration and land surface energy-balance partitioning by only using observations made by smartphone sensors. Individual variables known to effect evapotranspiration as measured by smartphone sensors generally showed a high correlation with routine observations during a multiday field test. In combination with a simple multivariate regression model fitted on observed evapotranspiration, the smartphone observations had a mean RMSE of 0.10 and 0.05 mm h -1 during validation against lysimeter and eddy covariance observations, respectively. This is comparable to an error of 0.08 mm h -1 that is associated with estimating the eddy covariance ET from the lysimeter or vice versa. The results suggests that smartphone-based ET monitoring could provide a realistic and low-cost alternative for real-time ET estimation in the field. [ABSTRACT FROM AUTHOR]

Transpiration efficiency (TE), the biomass produced per unit of water transpired, is a key trait for crop performance under limited water. As water becomes scarce, increasing TE would contribute to increase crop drought tolerance. This study is a first step to explore pearl millet genotypic variability for TE on a large and representative diversity panel. We analyzed TE on 537 pearl millet genotypes, including inbred lines, test-cross hybrids, and hybrids bred for different agroecological zones. Three lysimeter trials were conducted in 2012, 2013 and 2015, to assess TE both under well-watered and terminal-water stress conditions. We recorded grain yield to assess its relationship with TE. Up to two-fold variation for TE was observed over the accessions used. Mean TE varied between inbred and testcross hybrids, across years and was slightly higher under water stress. TE also differed among hybrids developed for three agroecological zones, being higher in hybrids bred for the wetter zone, underlining the importance of selecting germplasm according to the target area. Environmental conditions triggered large Genotype x Environment (GxE) interactions, although TE showed some high heritability. Transpiration efficiency was the second contributor to grain yield after harvest index, highlighting the importance of integrating it into pearl millet breeding programs. Future research on TE in pearl millet should focus (i) on investigating the causes of its plasticity i.e. the GxE interaction (ii) on studying its genetic basis and its association with other important physiological traits. [ABSTRACT FROM AUTHOR]

The Haihe Plain in China is situated in the world's largest groundwater funnel area, with per capita water resources far below the internationally recognized "extremely water-scarce" standard. To address the issue of water shortage in summer maize-planting areas of the Haihe Plain, we conducted research on the variation of summer maize evapotranspiration using a medium-sized lysimeter. This study aims to provide technical support for water-saving irrigation in summer maize fields. Through path analysis, direct and indirect influencing factors affecting the evapotranspiration of summer maize fields were determined. The results showed that the cumulative evapotranspiration of bare ground and farmland during the entire growth period of summer maize was 173.57 mm and 382.97 mm, respectively, with evapotranspiration intensities of 1.52 mm/d and 3.36 mm/d, respectively. Evapotranspiration during the maturity stage of summer maize was the least, accounting for only 1.82% of total evapotranspiration during the entire growth period. The period from the jointing to milk-ripening stage is when evapotranspiration in maize fields is at its highest. During this period, evapotranspiration in maize fields amounted to 265.58 mm, accounting for 69.35% of total evapotranspiration. The evapotranspiration intensity was 3.59 mm/day, which is 1.34 times higher than that of bare soil. The evapotranspiration intensities during each growth stage were ranked as jointing stage > tasseling-silking stage > seedling stage > milk maturity stage > maturity stage. The daily evapotranspiration of summer maize fields showed a "unimodal" curve with low values in the morning and evening, and high values at noon. Path analysis indicated that daily radiation and maximum daily temperature had the greatest impact on the evapotranspiration of maize fields, with the direct effect of maximum daily temperature being restrictive and the indirect effect being promotive, resulting in an overall promotive effect. [ABSTRACT FROM AUTHOR]

Introduction Agricultural water management studies require accurate information on actual evapotranspiration. This information must have sufficient spatial detail to allow analysis on the farm or basin level (Sanchez et al., 2008). The methods used to estimate evapotranspiration are grouped into two main groups, which include direct methods and indirect or computational methods (Alizade and Kamali, 2007). Basics of the indirect methods are based on the relationship between meteorological parameters, which impedes the use of these data with a lack or impairment. On the other hand, this information is a point specific to meteorological stations, and their regional estimates are another problem of uncertainty of their own. To this end, the use of remote sensing technology can be a suitable approach to address these constraints. Real evapotranspiration can be estimated by satellite imagery that has short and long wavelengths and is estimated using surface energy equations (Chihda et al., 2010). Examples of such algorithms include SEBAL (Bastiaanssen et al., 1998 Bastiaanssen, 2000;), METRIC (Allen et al., 2007), SEBS (Su, 2002). Among the above mentioned algorithms, energy billing algorithms have been used (Bagheriharooni et al., 2013; Teixeira et al., 2009). Among the factors of superiority of the SEBAL algorithm, in comparison with other remote sensing algorithms, is a satellite imagery analysis algorithm based on physical principles and uses satellite simulation and requires minimum meteorological information from ground measurements or air models (Bastiaanssen et al., 2002). Methodology In this research, 24 images from Landsat 8 satellite and 60 Sentinel 2 satellite images were used during growth period of sugarcane in 2016 and 2017, respectively (from May 28 to October 17 of each mentioned year). The study area is located in the Amir Kabir unit of Sugarcane Industry in the southern province of Khuzestan, one of the seven sugar cane cultivars and industries with local coordinates of 48 ° 16'49'E and 31 ° 2' 2'N. Amir Kabir Cultivation & Industry is located at Km 45 of Ahvaz - Khorramshahr Road, which is located south of Mirza Kuchak Khan's cultivation and is located in the east of Karoon's River. The total area of this farm was 15,000 hectares and its net area was 12,000 hectares, divided into several 25 hectares. The required meteorological information was extracted from the Amir Kabir Crop Production and Meteorological Station. This information includes: wind speed, sunshine hours, maximum and minimum temperatures, and rainfall. Results and Discussion The main objective of this study was to estimate the actual evapotranspiration of the sugarcane by using Landsat 8, Sentinel 2 and SEBAL algorithm. Finally, the results were compared with lysimetric data and analyzed. For statistical analysis of the results, the absolute difference indices and relative differences were used. In order to estimate evapotranspiration, as mentioned earlier, it was necessary to obtain the values of pure radiation and the heat flux for hot and cold pixels. The results are presented in Table 1, by separation of the evapotranspiration estimation method and the date of the images. Table (1) shows the potential evapotranspiration using the Taylor Presley method and the maximum values estimated by the SEBAL algorithm for Amir Kabir cultivation and industry. According to Table 1 the evapotranspiration rate calculated using the Taylor-Presley method is not significantly different from the evapotranspiration calculated by the SEBAL algorithm. In general, it can be stated that the method of using Landsat 8 and Sentinel 2 satellite images can calculate the amount of canopies evapotranspiration and transpiration with a small error value. the lysimeter gives the actual amount of evaporation and transpiration, by comparing the values of evapotranspiration calculated by the SEBAL algorithm and the values provided by the Lysimeter, the rate of error estimation indices represents less values. Therefore, according to Table (1), Sahbal algorithm is a suitable method for estimating the amount of evapotranspiration of cane sugar. ... The results showed that, despite the fact that the Sentinel 2 satellite does not have thermal bands, it is possible to calculate the actual evapotranspiration using the SEBAL algorithm by combining the satellite images with the Landsat satellite. Landsat satellite images are also challenging to estimate the water requirement, but according to the calculated indices, there is no significant difference with the lysimetric data. Compared to the combination of images, which have a precise accuracy in order to cover the time lag of Landsat 8 and Sentinel 2. Conclusions The SEBAL algorithm solves the energy balance equation to calculate the actual evapotranspiration of the plant, and the calculated parameters such as surface temperature, NDVI are defined in a certain range and are acceptable. The calculations showed that the results were consistent with the acceptable limits stated in the sources and statistics, and they confirmed this algorithm. Also, in comparison with the Taylor-Presley method, it was observed that SEBAL has calculated the actual evapotranspiration with acceptable results, which is also the reason for this method in calculating evapotranspiration. Due to errors in collecting climatic data such as wind speed, air temperature, solar radiation, day time duration, humidity, and also lack of calibration of coefficients such as coefficient of evaporation pan, plant coefficients for estimating evapotranspiration in many common error methods has it. In this regard, it is possible to consider new methods, such as the use of satellite imagery, to calculate the evapotranspiration of the plant for a wide range of plains as well as a point scale. It is obvious that by using suitable spatial resolution with homogeneity of the field farms and at appropriate time intervals, it is possible to plot the actual evapotranspiration of the plant for each region during the growing season. [ABSTRACT FROM AUTHOR]

Manure application performed in autumn requires regulation due to the risk of nitrogen (N) leaching during winter. On the other hand, application of manure in spring can pose some practical problems depending on the risk for N immobilization and the difficulty in ploughing heavy clay soils during this time of year. The risk for leaching is likely to differ between different soil texture and manure characteristics. In this study, we sought to estimate the risk for nitrogen leaching depending on the carbon/nitrogen ratio (C/N) of the manure, time for manure application, and soil type. We combined 3-year lysimeter experiments with 2-year field plot experiments and laboratory soil incubations and compared results with those from an empirical model. We compared effects of manure application on two soils (silty clay and loamy sand) and solid manures with different representing C/N ratios. In incubations, only manure with a C/N-ratio below 14 contributed with significant amounts of leachable N during the first months after application. In the lysimeter study, N leaching was unaffected by the timing of the application of the manure with C/N-ratio 18. However, regarding manure with C/N-ratio 10, N leaching was elevated with 10–15 kg N per ha after manure application in October compared to November and March on both soil types. The mineral N analyses from soil profiles in the field experiments showed a similar pattern, however, the increase was higher on the loamy sand compared to the silty clay. The ammonia emissions did not differ between manure types, but were on average 24% of applied NH4-N after application in October when air temperature was on average 12°C compared to only 3% of applied NH4-N in November and March when air temperature was on average 5°C. Similar to lysimeter results, the modelled N leaching was higher the earlier the manure application occurred in autumn. However, the model also predicted increased leaching for the manure with a high C/N-ratio, and a smaller effect on leaching on clay soil. Considering this, the model calculations overestimated the leaching effects from manure with a high C/N-ratio and underestimated the leaching effects on clay soil.

Snowfall/cover and snowmelt are essential determinants of winter soil processes/events that may force the biogeochemical dynamics of soils in temperate regions. Increasing variability of the European hydroclimate is expected to lead to more frequent intermittent warm periods, which cause snowmelt during winter and rapidly mobilize large amounts of dissolved organic matter (DOM). This study, conducted at the Hainich Critical Zone Exploratory in Germany, seeks to address a significant gap in understanding the molecular impacts of snowmelt-induced DOM flows and their ability to alter soil ecosystems rapidly. During two snowmelt events between January and March 2021, we observed that DOM concentration and composition varied more in forest soil seepage than in grassland soil seepage. Forest seepage showed a pronounced DOM flux peak and synchronous increases in the relative abundances of aromatic DOM components, indicating surface-derived transport of plant litter carbon. In the grassland, however, peak DOM fluxes were characterized by a marked increase in nitrogen-containing (N-containing) DOM components, indicating a predominance of microbial carbon. Notably, the unique DOM components specific to each ecosystem increased during peak fluxes in the forest but decreased in the grassland. We suggest that an overall higher molecular richness and the broader functional metabolic potentials in grassland may account for its relatively greater DOM stability compared to the forest during peak snowmelt events.

ABSTRACT The estimation of evapotranspiration (ET) and crop water requirements are crucial for the proper management and allocation of water resources in terms of quantity, quality, and timeliness. Therefore, remote sensing estimation of ET using the SEBAL algorithm (Surface Energy Balance Algorithm for Land) can provide spatio-temporal, non-punctual data, unlike traditional calculations relying on the nearest meteorological station. This research analyzed ET using SEBAL, based on ten Landsat 8 satellite images processed with a program developed in the Model Builder of ArcGis® version 10.2. The analysis was conducted during the vegetative period of starchy corn from May to October 2016. Validation of the results happened with a drainage lysimeter installed in a monitoring plot. Additionally, the statistical indices - such as percentage relative error (PRE) (0,09), root mean square error (RMSE) (0,30), R2 (0,92), and Nash-Sutcliffe efficiency (NASH) (0,91) - indicated a good correlation of ET for starchy corn in the central highlands of Peru. The ET identified at ten monitoring points ranged from 1,05 to 7,79 mm d-1.

Per- and poly-fluoroalkyl substances (PFAS) are a group of organo-fluorine compounds that have been broadly used in consumer and industrial products spanning virtually all sectors. They can be found as surfactants, coatings and liners, polymer additives, fire retardants, adhesives, and many more. The chemical stability of the carbon fluorine bond and amphiphilic nature of PFAS result in their persistence and mobility in the environment via soil porewater, surface water and groundwater, with potential for adverse effects on the environment and human health. There is an emergent and increasing requirement for fast, low-cost, robust, and portable methods to detect PFAS, especially in the field. There may be thousands of PFAS compounds present in soil and water at extremely low concentration (0.01–250 ppb) that require measurement, and traditional technologies for continuous environmental sensing are challenged due to the complexity of soil chemistry. This paper presents a comprehensive review of potentially rapid PFAS measurement methods, focused on techniques for representative sampling of PFAS in porewater from contaminated soil, and approaches for pre-treatment of porewater samples to eliminate these interferences to be ready for PFAS-detecting sensors. The review discusses selectivity, a key factor underlying pre-treatment and sensing performance, and explores the interactions between PFAS and various sensors. PFAS chemical nano-sensors discussed are categorized in terms of the detection mechanism (electrochemical and optical). This review aims to provide guidance and outline the current challenges and implications for future routine PFAS sensing linked to soil porewater collection, to achieve more selective and effective PFAS sensors.

A simple weighable lysimeter was designed, constructed, and calibrated for measuring the water requirements and crop coefficients of shallow-rooted crops. It has a portable weighing mechanism to quantify changes in soil moisture content. The weighing mechanism consists of a horizontal steel bar, a hydraulic car jack, both ends hooked vertical steel bars, a stand, and a digital weighing balance. As the lysimeter's inner tank, a plastic drum with a 55 cm diameter that yields 0.24 m2 of internal area was used. A performance test was conducted, and a rating curve was developed at the beginning of the growing seasons in 2023 and 2024 to evaluate the sensitivity of the weighing mechanism in determining crop water use. Linearity, repeatability, and measurement uncertainty tests were conducted. The linearity error was ±0.04 kg and ±0.03 kg for the years 2023 and 2024, respectively, which is within the allowable limit. The weighing system repeats the measurement perfectly with no error (repeatability error was zero). The combined uncertainty of the measurements was 0.023 kg, representing the cumulative effect of individual errors. The lysimeter weighing system is capable of detecting variations in mass as small as 0.2 mm of moisture content. Therefore, the developed lysimeter can be used to determine water requirements and crop coefficients of shallow-rooted crops for the design and management of irrigation in data-scarce areas of Ethiopia.

Background and aims: Organic farming has been viewed as a sustainable practice that can maintain yields and improve soil quality in greenhouse vegetable production. However, little attention has been given to the leaching of dissolved organic nitrogen (DON) due to excessive application of organic manure. The objectives of this study were to compare the characteristics of dissolved inorganic nitrogen (DIN) and DON leaching under different greenhouse vegetable production systems. Methods: A 2-year lysimeter field experiment was conducted with three different farming systems in North China, i.e. conventional (CON, 70% chemical fertilizer +30% organic manure), integrated (INT, 50% chemical fertilizer +50% organic manure) and organic (ORG, 100% organic manure). Results: The results indicated that vegetable yields under the ORG system were normally larger than the CON or INT. The amount of water drainage and dissolved total N (DTN, DIN + DON) leaching differed during two cropping seasons, with spring and summer seasons giving greater leaching than autumn and winter seasons. The total DIN leaching throughout four seasons of vegetable production under ORG was 176 kg N ha−1, which was much lower than that of CON (327 kg N ha−1) and INT (269 kg N ha−1). The DTN leaching under ORG (485 kg N ha−1) was also less than that of CON (528 kg N ha−1) and INT (521 kg N ha−1). However, the total DON leaching under the ORG was 309 kg N ha−1, far higher than the amounts for CON (202 kg N ha−1) and INT (252 kg N ha−1). The average DON leaching ratio (DON/DTN) under the ORG system was 63.7%, which was also much higher than that of the CON (38%) and INT (48%) systems. The increase in the proportion of organic manure in fertilizer types and over-irrigation were the main reasons for the increase in DTN leaching. Structural equation modeling analysis showed that the soil bulk density, saturated hydraulic conductivity and saturated soil water content were the most important factors influencing the DTN leaching. Conclusions: While the ORG system has many advantages, irrigation and fertilizer scheduling should be optimized under the ORG system in order to minimize DON leaching. [ABSTRACT FROM AUTHOR]

We developed a set of two precision, small-scale, water balance lysimeters to provide accurate measurements of bare soil evaporation. Each lysimeter comprises a soil tank, a balance assembly with load cell, a wicking drainage system, and a stilling well to measure drained water. Fiberglass wicks installed at the bottom of the soil tanks provide −60 cm of tension to the base of the soil column, and soil water drainage is quantified to close the water balance within the lysimeter. The calibrated lysimeters return mass changes with uncertainties ranging from 3 to 8 g, corresponding to uncertainties of 0.02–0.05 mm of water. Installed at a semi-arid site in northern Nevada, the two lysimeters are filled with uniform construction sand and silt loam. Over a six-month pilot observation period, bare soil evaporation rates of 0.19 and 0.40 mm/day were measured for the construction sand and silt loam, respectively, which is consistent with meteorological data and models of potential evapotranspiration at the site. The design of the lysimeter can be adapted to specific research goals or site restrictions, and these instruments can contribute significantly to our ability to close the soil water balance. [ABSTRACT FROM AUTHOR]

CLIMATE change is one of the most important global issues that impacts all our life sides. Growing crops and their productivity also are influenced by changing in the climate and climatic elements. Growing tea in non-traditional regions like Egypt could be considered a challenge due to the specific climatic and soil requirements for growing and production. However, with careful planning and experimentation, it might be possible to establish tea cultivation in such conditions. So, a lysimeter trial was conducted as an exploratory experiment aiming to assess tea cultivation performance in both sandy and clayey soil. Additionally, a separate field trial was carried out to evaluate tea growth in clayey soil along with applied organic fertilizer (chicken manure). The findings revealed that, under the lysimeter trial, tea plants exhibited robust growth on both sandy and clayey soil. Various parameters, including plant height, fresh and dry weights, leaf area, chlorophyll content, and leaf N, P, K levels, indicated superior performance on sandy soil compared to clayey soil. In the field trial, notable superiority was observed in plants grown on the organic medium containing chicken manure over those plants grown on clayey soil without such supplementation. These outcomes suggest that climate changes could potentially transform Egypt into a favorable region for tea cultivation. More studies are needed to establish a complete program of cultivation of tea including the water and nutrient requirements. [ABSTRACT FROM AUTHOR]

To gain a deeper understanding of the water balances of Alpine grassland ecosystems, it is crucial to know the abiotic and biotic drivers of evapotranspiration. The abiotic drivers are very heterogeneous in mountain regions because elevation, slope and aspect control incoming Rs, and atmospheric layering affect air temperature, humidity and wind distribution. In a study with 24 lysimeter plots distributed over a study area of approx. 300 km2 in the Eastern Alps, we covered a wide range of topographic conditions. We investigated the effects of abiotic drivers on evapotranspiration by measuring evaporation from a free‐water body (Ew). For the biological modulation of crop evapotranspiration (ETc), we analysed two different grassland types (at peak biomass and at low biomass) and calculated the respective crop coefficients (Kc). Results showed that primarily physical drivers such as the accumulated solar radiation from sunrise to measurement (Rs_acc), followed by atmospheric pressure (P), wind speed (u) and vapour pressure deficit (VPD) influence both Ew and ETc. Moreover, ETc is also significantly influenced by standing biomass and the grassland type (i.e., resource use strategies of the vegetation types) and by the geographic location along the valley (i.e., entrance, middle and head of the valley). We suppose plant stress and/or ground winds to be the underlying factor for the significance of the geographic location, yet further research is needed. The current study helps towards a better understanding of the water balance in alpine grassland ecosystems, but we also show that some spatial drivers cannot yet be adequately addressed. [ABSTRACT FROM AUTHOR]

The experiment was conducted using a lysimeter in June, 2014 in Saki (Derived Savanna) and Ile-Ife (Tropical Rainforest) to determine the crop coefficients and the effects of Urea fertilizer on the yield and water productivity of Amaranthus viridis in Nigeria. The loamy sandy soil in the top 15 cm was sampled, air-dried and analysed. Eighteen (18) kg of the air-dried and sieved soils were weighed into the thirty-two (32) lysimeters. Drill method was used for the sowing and the seeds were spread within 2 cm in the lysimeter. Urea fertilizer was applied at 0, 40, 80 and 160 kg N/ha twice during the growing season. The crop coefficients at the initial, mid, and late stages ranged from 0.15 to 0.41 in Ile-Ife, while in Saki, they ranged from 0.29 to 1.15 under Urea fertilizer. In Saki, the peak crop evapotranspiration was 1.21 mm/day for 0 kg N/ha of Urea while in the Ile-Ife, the crop evapotranspiration was 1.83 mm/day for 160 Kg N/ha of Urea. Water productivity in Saki and Ile-Ife were 45.47 kg/ha mm and 18.58 kg/ha mm respectively for 160 kg N/ha. This implies that Amaranthus viridis required more water during canopy expansion and flowering in Ile-Ife than in Saki. [ABSTRACT FROM AUTHOR]

Introduction: Despite various efforts to reduce nitrogen leaching from agricultural land, the permissible nitrate concentrations in groundwater have often been exceeded in the past. Intensive farming is often seen as the cause of the deterioration in water quality. Therefore, the present lysimeter study aimed to quantify nitrogen (N) leaching at different N fertilization levels for the agricultural land use systems of arable land and grassland to derive suitable management measures for improving groundwater quality. Methods: The effects of three different of mineral fertilization treatments (50%, 100%, and 150%) in arable land and grassland use on four distinct soil types (loamy sand, sand, loam, loess) concerning seepage formation, nitrogen concentrations, nitrogen loads, drymatter yields and nitrogen balances were tested. The study was conducted at the lysimeter facility of the Helmholtz Centre of Environmental Research - UFZ at Falkenberg (northeast Germany). Twenty-four non-weighable lysimeters with a surface area of 1 m² and a depth of 1.25 m were managed as grassland and arable land with three different fertilization treatments since 1985. Results and Discussion: For arable land use, N leaching differed between the studied soil types, with the highest N loads from the sand (36.6 kg ha-1 yr-1) and loamy sand (30.7 kg ha-1 yr-1) and the lowest N loads fromloess (12.1 kg ha-1 yr-1) and loam soil (13.1 kg ha-1 yr-1). In contrast to grassland use, a reduction of N fertilization level by 50 % did not result in reduced N leaching for arable land, whereas a maximal 29% reduced dry matter yields was observed. An increase of N fertilization by 50 % did not cause significant enhanced N leaching at arable land use. Soil-and management-related factors (soil type, texture, soil tillage, crop rotation, and others)mask the effect of increased N fertilization rates in arable land using lysimeters. For arable land use, a reduction of N fertilizer levels as the only measure was insufficient to reduce NO3- leaching, and other strategies besides N fertilization levels are required to improve groundwater quality. Measures should be targeted to reduce N losses by mineralization processes. [ABSTRACT FROM AUTHOR]

Groundwater pesticide safety management is essential for providing consistently safe water for humans, but such management is limited globally. In this study, we developed an accurate and convenient exposure assessment method for the safety management of pesticides in groundwater by conducting a lysimeter experiment to evaluate the leaching of 11 pesticides into groundwater. During the experimental period, flutoalanil and oxadiazon had the highest cumulative leaching amounts, 603.7 and 83.5 ng, respectively. Comparative analysis of existing groundwater exposure prediction indices, including the GUS, LEACH, modified LEACH, Hornsby index, and GLI showed no correlations with the measured data (p > 0.05). To enhance the accuracy of the assessment method, we used lysimeter data and principal component analysis to determine the main factors affecting groundwater leaching, and developed the "pesticide groundwater leaching scoring system" (PLS). The soil and water half-life, which had the greatest positive impact on groundwater leaching, was set as a 10-point indicator, whereas log P was set as a 1-point indicator. In contrast, solubility in water was determined as a 5-point indicator, and organic carbon partition coefficient and vapor pressure were determined as 2.5-point indicators owing to their negative relationship. The correlation coefficient was 0.670, indicating a significant correlation with the lysimeter data (p < 0.05). Using our scoring system, we ranked 376 pesticides. As an exposure assessment method developed using actual data, the PLS is expected to be applicable to groundwater safety management. [ABSTRACT FROM AUTHOR]

In tropical and subtropical island regions, alterations in precipitation patterns due to climate change have led to an escala- tion in extreme weather conditions. Owing to the limited availability of irrigation infrastructure, agricultural practices in these areas predominantly rely on rainwater and groundwater. The Optimized Subsurface Irrigation System (OPSIS), a water-efficient subsurface irrigation technology developed in Japan, was engineered to irrigate upland crops by harnessing soil capillarity. This study aimed to investigate soil water dynamics under OPSIS in a subtropical island located in Japan. The water supply from OPSIS in a field devoid of vegetation exhibited considerable variability contingent upon rainfall events. This observation implies that the infiltration of wa- ter captured by the waterproof sheet prompted the cessation of water supply in the OPSIS. Following the initiation of irrigation, soil water content increased at depths of 35 and 55 cm, proximal to the 60 cm depth from the OPSIS installation point, and soil moisture levels remained elevated, except at depths of 5 and 15 cm. Therefore, the implementation of OPSIS at a depth of 60 cm can effective- ly irrigate sugarcane with substantial water-saving benefits, except in the period immediately following planting. Irrigation and deep drainage were higher at 60 cm than at 30 cm depth of PVC sheet installation. To operate OPSIS with optimal water savings in areas with more severe water use restrictions, such as arid and semi-arid lands, controlling the irrigation of perforated pipes according to the soil moisture conditions in the effective root zone is essential. [ABSTRACT FROM AUTHOR]

Lysimetry has been acknowledged in the literature as the most effective means of assessing deep percolation rates through landfill final covers. Designing lysimeters requires several tools, including thorough laboratory testing and numerical modelling. This paper focuses on a fundamental boundary condition, namely breakthrough suction, and how it affects lysimeter design. This study was triggered by a multi-year database of suction and seepage data collected from a large-scale lysimeter constructed at the St-Nicephore landfill, Quebec, Canada. Tensiometers were installed at several levels near and at the interface between the cover material and the drainage layer inside the lysimeter, and outflow was measured using tipping counters. Based on field results and an analysis thereof, different geometry scenarios were simulated with HYDRUS-2D, and it was observed that in lysimeters designed using the linear method, breakthrough suction at the lower boundary can result in a greater than 90% percolation performance. With climate change, lysimeter percolation rate estimates may also be affected by rainfall events of varying magnitudes. Lastly, we were able to assess the existing design procedures and suggest a simple and conservative approach. [ABSTRACT FROM AUTHOR]

Determining the evapotranspiration (ET) of cotton as a water-intensive crop is crucial for effective irrigation planning and water management, especially in regions like Sindh province, Pakistan, where shallow groundwater table depths (WTDs) are prevalent. Despite the importance of cotton, a major cash crop in Sindh, previous studies on ET were conducted decades ago and may no longer be reliable due to ongoing climate change and the introduction of new crop varieties. Thus, we quantified cotton ET across two cropping seasons and at various WTDs (0.45, 0.60, 0.75, 1.50, 2.25, and 2.75 m). The experimental study was based on the data procured from 12 mini lysimeters and 12 large lysimeters for two years (2018 and 2019) and at two soil series. The findings revealed that cotton ET ranged from 1332 to 1437, 1114–1202, 988–1075, 781–821, 690–733, and 637–683 mm at WTDs of 0.45, 0.60, 0.75, 1.50, 2.25, and 2.75 m, respectively. WTDs from 0.45 to 0.75 m fulfilled 94–96 % of cotton ET through groundwater (GW) contribution in Sultanpur soil (silt loam) and 93–97 % in Miani soil (silty clay loam). At 1.50–2.75 m WTDs, irrigation water requirements (excluding rainfall and leaching) were 63–88 % in Sultanpur soil and 67–89 % in Miani soil. The highest yield was observed at a 1.50 m WTD, while the highest water use efficiency was identified at a 2.25 m WTD. However, soil salinity increased by 60–80 %, resulting in a 40–60 % lower cotton yield at 0.45–0.75 m WTD. Therefore, periodic flushing of salts is necessary to utilize shallow WTDs effectively. Considering GW contribution to ET when allocating water for irrigation channels and devising irrigation schedules is crucial. This approach can lead to water savings, prevent land from becoming waterlogged and saline, manage the groundwater table, and reduce the need for drainage channels and labor force for their preparation.

Excessive nitrogen (N) fertilization and irrigation prevail in irrigated agriculture worldwide. However, little information is available that systematically evaluates grain yield, plant N uptake, residual soil NO3−-N (RSN), and N leaching under different irrigation–N regimes in an irrigated maize production system. To address such agronomic and environmental issues, a 6-year in situ lysimeter field trial was conducted in the Hetao Irrigation District of China with five treatments: 1) conventional irrigation (3,900 m3/ha) and local farmer fertilizer N rate (490 kg ha−1) (CON); 2) conventional irrigation and the recommended fertilizer N rate (420 kg ha−1) (RN); 3) deficit irrigation (2,730 m3/ha) and the recommended fertilizer N rate (SRN); 4) deficit irrigation and the recommended fertilizer N rate (with ∼ 10 % organic fertilizer N substitution) (SMN); and 5) conventional irrigation and controlled-release N fertilizer (270 kg ha−1) (CRF). Maize yield was not significantly different across treatments in 2015–2020. Averaged across years, SMN, SRN, and CRF significantly increased plant N uptake compared with that in CON by 28.84 %, 19.15 %, and 17.53 %, respectively. Residual soil NO3−-N at 0–90 cm was ranked as SRN > CON ≈ SMN > RN > CRF, whereas cumulative N in leachate from 2015–2020 (Nloss) in CON was 86.2 % to 187.1 % higher than that in other treatments. The Nloss in SRN was equivalent to that in RN and SMN, but Nloss in SMN decreased significantly compared with that in RN, indicating additive benefits of deficit irrigation and organic input on reducing N leaching. Structural equation modelling revealed that irrigation had greater effects on plant N uptake than those of fertilization, whereas N rate had a greater total effect on N leaching than that of irrigation. Overall, rampant excessive irrigation and N fertilization by farmers can be substantially reduced while maintaining grain yield and mitigating N leaching loss, with further benefits gained by applying controlled-release N fertilizer and manure in irrigated maize production.

Purpose: to study the dynamics of moisture in soils on the drainage layer during drip irrigation to save water resources and ensure uniform watering of crops using moisture contours. Materials and methods. The study is based on the theory of moisture transfer under the influence of drip irrigation on soil. Moisture contours were studied in laboratory conditions using a soil lysimeter, which was used to model the geological cross-section of the irrigated area, represented by alluvial meadow soils formed on pebbles. The pebble layer thickness was assumed to be up to 3 m. A regression analysis of moisture movement was carried out, and a mathematical model describing the nature of its movement on the drainage layer was obtained. The estimated volume of wet soil was defined on the basis of moisture contours as a result of calculating the volume of the formed lathe object using cartograms for each hour of irrigation. Results. Data on the moisture distribution in soil profile according to irrigation hours, presented on cartograms constructed using a personal computer, were obtained. The contours with the same humidity – isolines on which the humidity was displayed: 5; 10; 40 % are highlighted on the cartograms. It has been determined that water at an emitter discharge of 2.5 l/h reaches the drainage layer 4 hours after the beginning of irrigation. The graph for moisture distribution in soil volume by hour, reflecting the dynamics of water distribution supplied from an emitter with a constant discharge over 10 hours of irrigation has been constructed. Conclusion. The dynamics of moisture distribution during drip irrigation in soils located on a drainage bed was studied. Under experimental conditions, when crop irrigation lasts for more than 8 hours, an ineffective excess of irrigation rate and an increase in the design capacity of the drip irrigation system are observed.

The upward movement of water through capillary rise from the shallow water-table (1–1.5 m) to the root zone (0.4–0.6 m) is an important incoming flux in the soil system. UPFLOW is a specialized model for determining capillary rise, which is a simple model with a small amount of input data. This research was conducted to assess the efficiency of the UPFLOW model in the simulation of capillary rise in shallow water-table conditions, based on the observed capillary rise using a lysimeter in the agro-industry of Amirkabir, Khuzestan. The input data of the model include: crop(root-water uptake rate at different sections of root zone, crop cover type, crop coefficient), soil(number of soil layers and their thickness, mean soil-water content of the profile, anaerobiosis point of the soil, saturated hydraulic conductivity of the soil profile), weather(maximum and minimum temperature, solar radiation, wind speed, and relative humidity, ET0) and water-table(depth to water-table from the soil surface, salt content of the groundwater) were measured. Then, the capillary rise was calculated for each month during the stages of sugarcane growth. The performance of this model was evaluated by the statistical indices including determination coefficient (R2), mean absolute error (MAE), root mean square error (RMSE), relative error (RE), and model efficiency (EF). The results of the field measurement showed that the highest amount of capillary rise (1.6 mm) was observed in July, with the maximum evapotranspiration (400 mm) and the maximum growth of sugarcane. The lowest value (0 mm) also was observed in the months when sugarcane growth stopped, i.e., November, December, January, and February. The results of this research have shown that the UPFLOW model in the studied area has not shown suitable efficiency (based on statistical indicators) in the simulation of the upward flow in specific conditions of water-table, crop, soil, climate, and management measures (R2:0.23, MAE:8.71, RMSE:9.10, RE:180.50, EF: -136.40). Therefore, this model, in shallow water-table conditions, to accurately estimate capillary rise, requires comprehensive evaluations of various effective factors and, if possible, to modify and adjust this model in this area.

As urbanization intensifies environmental challenges in contemporary cities, widespread green roof installations emerge as a potential solution. This study explores irrigating tall fescue (Festuca arundinacea Schreb.) turfgrass with saline water in extensive green roof systems, aiming to conserve freshwater resources. The objectives include determining the period of saline water tolerance and identifying the leachate electrical conductivity threshold affecting tall fescue's green coverage. This greenhouse study comprised 24 lysimeters equipped with extensive green roof layering. Treatments included three NaCl irrigation solutions with an electrical conductivity of 3 dS m−1, 6 dS m−1, and 9 dS m−1, while tap water served as the control. Additionally, irrigation treatments were applied at two different regimes, resulting in an average leaching fraction of 0.3 for the low irrigation regime and 0.5 for the high irrigation regime. Tall fescue's tolerance to saline water was evaluated through the determination of green turf cover (GTC) as well as the clipping dry weight and the leachate electrical conductivity (ECL) draining from the lysimeters. It was found that tall fescue turfgrass growing in extensive green roof systems can tolerate irrigation with water of electrical conductivity up to 9 dS m−1 for extended periods, approximating three months, without GTC declining below 90%, provided that a minimum leaching of 30% is maintained. Furthermore, irrigating with water at 9 dS m−1 resulted in a 24.5% reduction in cumulative clipping dry weight over the four-month study period. The regression analysis between GTC and ECL highlighted a substantial decline in GTC when ECL surpassed the critical threshold of 12.5 dS m−1. [ABSTRACT FROM AUTHOR]

Evapotranspiration plays a key role in the terrestrial water cycle, climate extremes and vegetation functioning. However, the understanding of spatio-temporal variability of evapotranspiration is limited by a lack of measurement techniques that are low-cost, and that can be applied anywhere at any time. Here we show that evapotranspiration can be estimated accurately using only observations made by smartphone sensors. Individual variables known to effect evapotranspiration generally showed a high correlation with routine observations during a multi-day field test. In combination with a simple ML-algorithm trained on observed evapotranspiration, the smartphone-observations had a mean RMSE of 0.10 and 0.05 mm/h when compared to lysimeter and eddy covariance observations, respectively. This is comparable to an error of 0.08 mm/h when estimating the eddy covariance ET from the lysimeter or vice versa. The results suggests that smartphone-based ET monitoring could provide a realistic and low-cost alternative for real-time ET estimation in the field. [ABSTRACT FROM AUTHOR]

In Romania, evapotranspiration at bare soil or covered by crops is monitored within the experimental evapotranspiration stations: Căldărușani, Voinești and Poiana Brașov. Many experimental researches are carried out, in order to analysed the variation of crop evapotranspiration, in relation to the climatic parameters and soil moisture. The experiments carried out in recent years, have shown that starting from 2021 until 2023, at the level of G1 lysimeters, no more infiltrated water quantities were recorded, so all the amount of water was evaporated. It was also observed that in the year 2022 the sunflower and maize crops did not reach the stage of maturity. In 2023, an experiment was carried out that aimed to compare the maize evapotranspiration in a natural regime and exposed to additional watering (Căldărușani station). The water addition rate was established based on specialized literature and by applying CropWat model. Additional waterings generated different evapotranspiration values. The waterings changed the values of soil moisture and helped the plant not to reach the wilting point before ripening. [ABSTRACT FROM AUTHOR]

Soil–hydrophysical research substantiating the mathematical models of water movement, taking into account the soil heterogeneity, due to the vertical change in texture, is considered. The vertical movement of water on large-size lysimeters of the Federal Scientific Center of Agroecology of the Russian Academy of Sciences (Volgograd) was studied. The influence of statistical heterogeneity of hydrophysical parameters of lysimeter substrates was studied on models of water transfer dynamics and formation of gravitational runoff developed in the HYDRUS-1D software package. The change in texture along the vertical profile of the lysimeters and the related variability of the main hydrophysical characteristic or water retention curve (WRC) were taken into account. The textural heterogeneity of the substrates was estimated by the scaling method, according to the scale factors of the WRC parameters, assuming a normal probability distribution of the logarithms of the pore space capillary radii between soil particles. The effect of texture on water holding capacity, boundary and initial conditions, intensity of gravitational runoff and cumulative accumulation of water were studied. [ABSTRACT FROM AUTHOR]

The upward movement of water through capillary rise from the shallow watertable (1-1.5 m) to the root zone (0.4-0.6 m) is an important incoming flux in the soil system. UPFLOW is a specialized model for determining capillary rise, which is a simple model with a small amount of input data. This research was conducted to assess the efficiency of the UPFLOW model in the simulation of capillary rise in shallow water-table conditions, based on the observed capillary rise using a lysimeter in the agro-industry of Amirkabir, Khuzestan. The input data of the model include: crop(root-water uptake rate at different sections of root zone, crop cover type, crop coefficient), soil(number of soil layers and their thickness, mean soil-water content of the profile, anaerobiosis point of the soil, saturated hydraulic conductivity of the soil profile), weather(maximum and minimum temperature, solar radiation, wind speed, and relative humidity, ET0) and water-table(depth to water-table from the soil surface, salt content of the groundwater) were measured. Then, the capillary rise was calculated for each month during the stages of sugarcane growth. The performance of this model was evaluated by the statistical indices including determination coefficient (R²), mean absolute error (MAE), root mean square error (RMSE), relative error (RE), and model efficiency (EF). The results of the field measurement showed that the highest amount of capillary rise (1.6 mm) was observed in July, with the maximum evapotranspiration (400 mm) and the maximum growth of sugarcane. The lowest value (0 mm) also was observed in the months when sugarcane growth stopped, i.e., November, December, January, and February. The results of this research have shown that the UPFLOW model in the studied area has not shown suitable efficiency (based on statistical indicators) in the simulation of the upward flow in specific conditions of water-table, crop, soil, climate, and management measures (R²:0.23, MAE:8.71, RMSE:9.10, RE:180.50, EF: -136.40). Therefore, this model, in shallow water-table conditions, to accurately estimate capillary rise, requires comprehensive evaluations of various effective factors and, if possible, to modify and adjust this model in this area. [ABSTRACT FROM AUTHOR]

Preferential flow is ubiquitous in soils, and it affects water infiltration, runoff, and contaminant transport. Undisturbed soil lysimeters (n = 10; 900 cm2) were collected from an agricultural field to quantify the effect of climate, soil moisture, connectivity, and agricultural practices on water transport through the shallow vadose zone. A series of 10 rainfall simulations was conducted on each lysimeter (n = 100 events) and data were analysed within a framework of five case studies where we assessed the impact of rainfall intensity (n = 30 events), soil moisture (n = 28), and tillage (n = 21). Three lysimeters that had near‐zero flow initially were modified to investigate dynamics of direct surface connectivity through an artificial macropore in which we assessed the impacts of soil moisture (n = 12) and subsequent disruption via tillage (n = 9). Stable water isotopes were used to separate leachate into event (Qe) and pre‐event water (Qpe). Results showed that event water transport in leachate was not affected by rainfall intensity (Qe/Q = 49% ± 21% to 50% ± 24%); however, event water decreased from 65% ± 5% to 23% ± 28% with increasing soil moisture. Lysimeters with artificial macropores resulted in leachate that was nearly all event water (85% ± 12% to 92% ± 4%) irrespective of soil moisture. Tillage decreased event water transport for both lysimeters with and without an artificial macropore by ~30%. Findings show how varying initial and boundary conditions produce a continuum of preferential flow. Water and tracer flux data collected in the current study are therefore essential for predicting conditions with high relevance of preferential flow and contaminant transport when assessing or modelling long‐term hydrographs where these conditions are only met during a small proportion of the flow time. [ABSTRACT FROM AUTHOR]

The construction of modern lysimeters with a precise weighing system made it possible to achieve an unprecedented accuracy of precipitation measurement. This study compares two methods of measuring precipitation in the conditions of the humid continental climate of the Eastern Slovakian Lowland (Slovakia): measurement using a standard tipping-bucket rain gauge vs. precision weighable lysimeter. Data from the lysimeter were used as a reference measurement. The comparison period lasted four years (2019–2022). Only liquid rainfall was compared. The rain gauge was found to underestimate precipitation compared to the lysimeter. Cumulative precipitation for the entire monitored period captured by the rain gauge was 2.8% lower compared to lysimeter measurements. When comparing hourly and daily totals of precipitation and precipitation events, a very high degree of agreement was detected (r2 > 0.99; RMSE from 0.22 to 0.51 mm h–1). A comparison based on precipitation intensity showed a decreasing trend in measurement accuracy with increasing precipitation intensity. This tendency has an exponential course. With increasing intensity of precipitation, increasing intensity of wind was also recorded. In order to correct measurement errors, simple correction method was proposed, which helped to partially eliminate the inaccuracies of the rain gauge measurement. [ABSTRACT FROM AUTHOR]

IntroductionDespite various efforts to reduce nitrogen leaching from agricultural land, the permissible nitrate concentrations in groundwater have often been exceeded in the past. Intensive farming is often seen as the cause of the deterioration in water quality. Therefore, the present lysimeter study aimed to quantify nitrogen (N) leaching at different N fertilization levels for the agricultural land use systems of arable land and grassland to derive suitable management measures for improving groundwater quality.MethodsThe effects of three different of mineral fertilization treatments (50%, 100%, and 150%) in arable land and grassland use on four distinct soil types (loamy sand, sand, loam, loess) concerning seepage formation, nitrogen concentrations, nitrogen loads, dry matter yields and nitrogen balances were tested. The study was conducted at the lysimeter facility of the Helmholtz Centre of Environmental Research – UFZ at Falkenberg (northeast Germany). Twenty-four non-weighable lysimeters with a surface area of 1 m² and a depth of 1.25 m were managed as grassland and arable land with three different fertilization treatments since 1985.Results and DiscussionFor arable land use, N leaching differed between the studied soil types, with the highest N loads from the sand (36.6 kg ha–1 yr–1 ) and loamy sand (30.7 kg ha–1 yr–1 ) and the lowest N loads from loess (12.1 kg ha–1 yr–1) and loam soil (13.1 kg ha–1 yr–1). In contrast to grassland use, a reduction of N fertilization level by 50 % did not result in reduced N leaching for arable land, whereas a maximal 29% reduced dry matter yields was observed. An increase of N fertilization by 50 % did not cause significant enhanced N leaching at arable land use. Soil-and management-related factors (soil type, texture, soil tillage, crop rotation, and others) mask the effect of increased N fertilization rates in arable land using lysimeters. For arable land use, a reduction of N fertilizer levels as the only measure was insufficient to reduce NO3– leaching, and other strategies besides N fertilization levels are required to improve groundwater quality. Measures should be targeted to reduce N losses by mineralization processes.

The Haihe Plain in China is situated in the world’s largest groundwater funnel area, with per capita water resources far below the internationally recognized “extremely water-scarce” standard. To address the issue of water shortage in summer maize-planting areas of the Haihe Plain, we conducted research on the variation of summer maize evapotranspiration using a medium-sized lysimeter. This study aims to provide technical support for water-saving irrigation in summer maize fields. Through path analysis, direct and indirect influencing factors affecting the evapotranspiration of summer maize fields were determined. The results showed that the cumulative evapotranspiration of bare ground and farmland during the entire growth period of summer maize was 173.57 mm and 382.97 mm, respectively, with evapotranspiration intensities of 1.52 mm/d and 3.36 mm/d, respectively. Evapotranspiration during the maturity stage of summer maize was the least, accounting for only 1.82% of total evapotranspiration during the entire growth period. The period from the jointing to milk-ripening stage is when evapotranspiration in maize fields is at its highest. During this period, evapotranspiration in maize fields amounted to 265.58 mm, accounting for 69.35% of total evapotranspiration. The evapotranspiration intensity was 3.59 mm/day, which is 1.34 times higher than that of bare soil. The evapotranspiration intensities during each growth stage were ranked as jointing stage > tasseling-silking stage > seedling stage > milk maturity stage > maturity stage. The daily evapotranspiration of summer maize fields showed a “unimodal” curve with low values in the morning and evening, and high values at noon. Path analysis indicated that daily radiation and maximum daily temperature had the greatest impact on the evapotranspiration of maize fields, with the direct effect of maximum daily temperature being restrictive and the indirect effect being promotive, resulting in an overall promotive effect.

The Longdong Loess Plateau is an important rainfed agricultural area in China.It is of great significance to study the differences of land surface processes under different farmland for understanding the regional land-atmosphere interaction.Based on the farmland micrometeorological and lysimeters observation data of Qingyang City， Gansu Province from June 2021 to May 2022， this paper analyzed the differences in microclimate and evapotranspiration characteristics of three different crops： apple， corn， and wheat； combined with correlation analysis and sensitivity analysis， the main influencing factors of evapotranspiration from the underlying surface of different crops were discussed.The results showed that： （1） The temperature and land-air temperature difference in the apple field were smaller during the growing period； the relative humidity of corn field was higher than that of wheat field， especially in the canopy； the surface albedo of corn field was basically lower throughout the year， but it increased in May due to covering with mulch film， and its annual average net radiation was significantly lower than that of the apple field and wheat field； （2） The daily variation of evapotranspiration basically followed the mid-growth stage > the early growth stage > the maturity stage， the evapotranspiration of corn was the largest in the mid-growth period， reaching a maximum of 4.9 mm·d-1， and the annual daily evapotranspiration of wheat field was less than 3 mm·d-1.during the whole growth period， the change of daily evapotranspiration of apple field was the most， while that of wheat field was relatively stable； （3）Net radiation was the main meteorological driving factor for evapotranspiration change in apple field and corn field during the growing period， but it had relatively little effect in wheat field； the sensitivity of evapotranspiration to saturated water vapor pressure difference in the growing period of the three places was smaller than that in the non-growing period.

Introduction and Objective Due to droughts occurred in recent years, available water resources in southern basins and watersheds of Iran especially those are in Hormozgan Province has been drastically decreased which may not only change their ecosystem but also make serious problem for the country’s food security. In addition to find new water resources, effective use of available water is the best choice to tackle water deficit which in turn, requires accurate estimation of evapotranspiration or water needs of plants. Crop evapotranspiration is usually calculated using the two-step FAO method. In this method, first the reference crop evapotranspiration (ET0), representing effect of weather on crop evapotranspiration is estimated by models using weather variables and then, multiplied by crop coefficient (Kc) which reflects crop characteristics on evapotranspiration. A review on the research conducted around the world revealed that each model may have different accuracies and performances at different watersheds or locations. Subsequently, using these models without testing their accuracy and relevance at each watershed may increase error in estimating (ET0) and hence crop water requirements which may complicate any planning for the watershed in the future. Therefore, this research was conducted to evaluate the accuracy and performance of the FAO proposed models at Haji Abad watershed of Hormozgan Province.Materials and Methods In this research which was conducted in Haji Abad watershed of Hormozgan for four years, reference crop(grass) evapotranspiration was measured weekly using a drainable lysimeter. In the first year, a large square drainable lysimeter (3 m wide ×3 m long × 1.9 m tall) was installed in the center of a 2-ha agricultural field which was representative of the watershed. In the next third years, grass (Cynodon dactylon L.) was grown inside the lysimeter and in the 900 m2 surrounding field. At full cover and when grass height reached 8 cm, evapotranspiration from grass inside the lysimeter was measured weekly by the water balance method. Reference crop evapotranspiration was also estimated using the FAO models: Adjusted penman and Blaney- Criddle, Radiation, Evaporation pan and Penman-Monteith. The estimated (ET0) values from the FAO models were compared with the data measured from lysimeter using linear regression, root mean square error and error percentage in estimating seasonal (ET0) and subsequently, the most appropriate models were recommended for the watershed.Results and Discussion Seasonal grass evapotranspiration measured from the lysimeter was 2729.8 mm and estimated by Adjusted penman and Blaney- Criddle, Penman-Monteith, Radiation and Evaporation pan 3405, 2695.2, 2868, 2789.2 and 2054.6 mm, respectively. The FAO adjusted Penman, Penman-Monteith and Radiation models overestimated ETo by as much as 24.7, 5.1 and 2.2% respectively, whereas, the FAO evaporation pan and Blaney- Criddle underestimated it by as much as 24.7 and 1.3%, respectively. Comparing weekly (ET0) data showed that adjusted penman model overestimated (ET0) but the FAO evaporation pan model underestimated it for most of the periods. FAO radiation model had tendency to overestimate at ETo10 mmday-1 (normally in Summer).Conclusion and Suggestions According to the results, the FAO Blaney-Criddle and Penman-Monteith models had respectively higher accordance and homogeneity with the real data measured from lysimeter and can predict (ET0) with higher accuracy than the other tested models. Therefore, these models are recommended, respectively as the most appropriate models to estimate (ET0) in Haji Abad Watershed and the areas having the same climate. Furthermore, the FAO Blaney-Criddle model needs fewer weather parameters and hence, may be used in the areas with limited climatic data.

Two separate experiments were conducted to investigate the performance of peppermint (Mentha piperita L.) in different water deficit and salinity management in 2017 and 2018, a randomized complete block design factorial experiment with three replications was designed in a lysimeter station in the Department of Water Engineering, Campus Agriculture, and Natural Resources of Razi University, Iran. The experiment included three levels of irrigation: 100%, 80% and 60%, and four salinity levels: (control), 2, 3 and 4 dS/m. The results indicated that the water deficit stress effect on aerial characteristics (leaf fresh weight, shoot fresh weight, leaf area, shoot height) and underground organs (root dry weight, root volume, root area, and root length), was significant. The irrigation water salinity effect in two years of the experiment was significant on leaf wet and dry weight, shoot wet and dry weight, leaf area and root dry weight, root volume, root area and root length. The mean comparison test revealed that the effect of deficit irrigation on shoot wet and dry weight was not significant between the 80% and 60% water requirement treatments. For 100% and 60% of irrigation requirements, the maximum and minimum leaf dry weight was observed at 2.47 and 1.54 g/plant in 2017. The mean comparison test result for salinity on underground organs showed that the highest root length in two years was observed in the control treatment and the lowest value of this parameter was observed in the 4 dS/m treatment. In general, water deficit and salinity had a negative effect on peppermint yield during two years of experiments. Therefore, it is not recommended to apply water stress and use water with a salinity of more than 2 ds/m to achieve the maximum yield.

Cultivation of medicinal plants with the irrigation of agricultural effluents might be of great importance to save fresh water resources, extend cultivation area and increase economic feasibility. We investigated the effects of saline fish farm effluent water, diluted and gypsum-supplemented effluent, and natural freshwater as a control irrigation in lysimeters. Beside plant growth parameters, macronutrient and sodium content and the amount and composition of essential oil of sage plants were measured. Significant differences among irrigation treatments were found in plant height, SPAD value and essential oil content. Seasonal variation was also observed on plant height, nutrient content of the leaves and the total essential oil content. The essential oil components characterised by the highest levels of availability were detected as α-thujone, camphor, ß-thujone, 1,8-cineol and ledol. Under effluent irrigation, the concentrations of - and ß-thujone increased slightly; only camphene, trans-sabinole and caryophyllene-oxide changed significantly. The other main components remained stable. Our analysis of the response of sage to the input of effluent provides a reasonable ground for recommending the utilisation of saline effluent water from intensive fish farming in sage production, thus preventing the wastage of valuable water resources.

Cultural and environmental factors can place creeping bentgrass (Agrostis stolonifera) under extreme stress during the summer months. This stress, coupled with the growth adaptation of creeping bentgrass, can result in shallow, poorly rooted stands of turf. To enhance root zone oxygen and rooting of creeping bentgrass, golf courses use methods such as core and solid-tine aerification, and sand topdressing. An additional method of delivering oxygen to the soil could be irrigation with nanobubble-oxygenated water. The properties of nanobubbles (NBs) allow for high gas dissolution rates in water. Irrigating with NB-oxygenated water sources may promote increased rooting of creeping bentgrass putting greens during high-temperature periods and lead to a more resilient playing surface. The objectives of this study include comparing the effects of irrigation with NB-oxygenated water sources with untreated water sources on creeping bentgrass putting green root zone and plant health characteristics using field and controlled environment experiments. Treatments included NB-oxygenated potable water and irrigation pond water, and untreated potable and irrigation pond water. In the field, NB-oxygenated water did not enhance plant health characteristics of creeping bentgrass. In 1 year, NB-oxygenated water increased the daily mean partial pressure of soil oxygen from 17.48 kPa to 18.21 kPa but soil oxygen was unaffected in the other 2 years of the trial. Subsurface irrigation with NB-oxygenated water did not affect measured plant health characteristics in the greenhouse. NB-oxygenation of irrigation water remains an excellent means of efficiently oxygenating large volumes of water. However, plant health benefits from NB-oxygenated irrigation water were not observed in this research.

This study quantified the total evapotranspiration (ET) flux of three major types of macrophytes that cover lacustrine fringe wetlands in Lake Tana, Ethiopia during the dry season, April and May, 2022. This study was conducted to understand lacustrine wetland macrophytes' ET rates and provide an important guideline for designing their conservation and restoration plans. To assess ET rates during the peak dry season, three macrophytes of lacustrine wetlands in Lake Tana were chosen: Eichhornia crassipes (water hyacinth), Cyperus papyrus, and Echinochloa stagnina. Three replicate lysimeters for each of the three treatment types (macrophytes) and one control type (open water) were applied to measure ET. To calculate reference evapotranspiration (ET o), FAO's ET o Calculator Version 3.2 was applied. All statistical analyses were carried out using R software. The results of ET rates from wetland macrophytes (9.05mm/day) were considered to be significantly higher than open water evaporation (5.90mm/day). There was a significant difference in mean ET among the macrophytes [F (3, 488) = 194.6, p < 2e-16 ***]. In this study, crop coefficient (K c1) (1.99 ± 0.65) referenced to FAO Penman–Monteith ET o is greater than K c2 (1.58 ± 0.59) referenced to open water evaporation (E ow). In terms of wetland macrophyte type, E. crassipes had the maximum mean Kc values (K c1 = 2.51±0.70 and K c2 = 2.02±0.67). E. stagnina had the minimum mean Kc values (K c1 = 1.52±0.32 and K c2 = 1.19±0.24). Except for open water which strongly correlated with sunshine hours (r = 0.61) and solar radiation (r = 0.60), the correlation among daily ET values and meteorological variables was found to be weak. The result of our research indicated that the presence of floating macrophytes of E. crassipes will increase the ET flux during the dry season more than emergent macrophytes and open water surfaces. Our findings could provide an important guideline for designing conservation and restoration plans for C. papyrus and E. stagnina to reverse the spread of E. crassipes and maintaining lacustrine fringe wetlands for fish breeding ground and sediment control. [ABSTRACT FROM AUTHOR]