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Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Agricultural Resources & Environment / Nongye Ziyuan yu Huanjing Xuebao is the property of Journal of Agricultural Resources & Environment Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As a highly heterogeneous soil, its spatial variability has seriously affected the formulation of precise management measures for water and salt in farmland and the efficient use of farmland water and soil resources. The purpose of this paper was to study the spatial distribution characteristics and spatial variability of soil water, salinity and heat in large scale region. Taking the Baotou Lake region of Xinjiang as an example, the soil samples were taken about 1 week after the spring irrigation, and soil moisture, salinity, bulk density, and particle composition were measured. The spatial distribution characteristics of water, salt, thermal parameters were analyzed by using a combination of classical statistics and geostatistics and GS+ software and ARCGIS software were used to process the data. The soil moisture, salinity, and soil texture were analyzed. The soil thermal conductivity and soil heat capacity were calculated. The spatial distribution feature maps were plotted. The results showed that soil moisture and salinity gradually increased with the increase of soil depth. According to the classification standard of Xinjiang Soils, the soil in the studied area belonged to the moderate salinized soil. The overall thermal conductivity of the soils were low, with a minimum value of 0.134 W/(m∙K) and a maximum value of 0.732 W/(m∙K). The soil thermal conductivity averaged around 0.5 W/(m∙K). The soil heat capacity increased with the increase of soil depth. The maximum value was 3.004 J/(m∙K) and the minimum value was 1.321 J/(m∙K). The soil bulk density had a weak variability; soil moisture content, thermal conductivity and heat capacity all had moderately weak variability; soil salinity had a strong variability. The semivariogram functions of soil moisture, soil salinity and soil thermal conductivity could be fitted by Gaussian models. The semivariance function of soil heat capacity could be fitted by an exponential model. There was a strong spatial dependence between the soil moisture at the same depth. The random factors accounted for low degree of total variation. The maximum correlation distance was 2.6 km-3.9 km. The sampling distance was about 1.5 km, which was reasonable. The spatial distribution maps of salt salinity interpolated by Kriging interpolation showed that the soil moisture was low in the middle area of the study area and increased from the east to the west. The Kriging interpolation showed that the soil salinity had an increasing trend from north to south. With the increase of soil depth, the peak area of the “circular” peak area gradually decreased and the shape formed a strip distribution area. And the lower values of the thermal conductivity of the surface soil were mainly distributed in the northeast-southwest direction, and the distribution belt with lower values gradually shifted westward as the soil depth increased. At the soil depth of 20-40 cm, there was a relatively significant positive correlation between soil moisture and salinity, and the range of positive correlation was about 1 km. This research results could provide valuable information for local agricultural irrigation and precision agriculture production. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The fresh water resource shortage severely increased in some regions, and the reasonable application of brackish water could alleviate the contradiction between water supply and demand. Hence, effective measures should be taken to regulate the condition of soil water and salt under brackish water irrigation. De-electronic water treatment technology is a new physical water treatment technology, which has received increasing attention in recent years. In order to improve the efficiency of brackish water utilization and alleviate the shortage of agricultural water supply, the de-electronic processor device was used to treat the brackish water with different salinity (0.14, 2, 3, 4 and 5 g/L), and the effect of de-electronic brackish salinity on water and salt movement in soil was revealed by a vertical infiltration experiment. The results showed that the soil infiltration rate and wetting front migration rate were significantly improved by the infiltration of de-electronic brackish water, and it would be varied under different salinity of brackish water. When the salinity of de-electronic brackish water was 3 g/L, the cumulative infiltration amount and wetting front depth reached the maximum at the end of infiltration. Compared with untreated brackish water, the de-electronic brackish water had a maximum relative cumulative infiltration amount and wetting front depth under brackish water condition of 4 g/L salinity. When the infiltration time was 200 min, the cumulative infiltration amount and wetting front depth were relatively increased by 20.5% and 23.1%, respectively, and the infiltration time was reduced by 34.4% after infiltration. The parameters of Philip and Green-Ampt formulas were significantly influenced by de-electronic brackish water. The soil treated by de-electronic brackish water had a greater value of soil sorptivity, saturated hydraulic conductivity and wetting front suction than untreated brackish water. The relationship between sorptivity and salinity of de-electronic brackish water can be described by a quadratic polynomial equation. And the effect of brackish water salinity on saturated hydraulic conductivity can be described by a quadratic polynomial equation as well. When the salinity was 3 g/L, sorptivity and saturated hydraulic conductivity reached the maximum under both conditions of de-electronic brackish water and untreated brackish water. Moreover, de-electronic brackish water could enhance soil water retention capacity and salt leaching effect. For the same soil depth, the soil moisture content increased significantly, especially in the depth range of 20-25 cm. The soil water content within the depth of 20-25 cm relatively increased by 29.5% at the salinity of 4 g/L. Saline content and Na+ content at the depth of 27 cm were obviously higher than that of untreated brackish water after infiltration. The salt and Na+ relative leaching rates were 16.5% and 19.9% respectively at 4 g/L brackish water. And it had a great desalination effect owing to the highest salt and Na+ relative leaching rates. The results of this study prove that de-electronic brackish water can improve soil water movement and enhance salt leaching effect. Meanwhile, the utilization rate of brackish water can be significantly increased. This study can provide a theoretical support for the application of de-electronic brackish water in agriculture irrigation. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Drainage & Irrigation Machinery Engineering / Paiguan Jixie Gongcheng Xuebao is the property of Editorial Department of Drainage & Irrigation Machinery Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Drainage & Irrigation Machinery Engineering / Paiguan Jixie Gongcheng Xuebao is the property of Editorial Department of Drainage & Irrigation Machinery Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Groundwater quality is closely related with human health and environmental safety. In the suburb of Beijing, the groundwater quality is heavily concerned. In this study, the groundwater quality in Changping piedmont plain was evaluated based on the single factor evaluation method and comprehensively evaluated based on BP neural network. The Changping district is located was in the northwestern area of Beijing. Considering that the main area affected by human activity was the shallow groundwater, we arranged a total of 12 monitoring wells around the plain area. The depths of wells 1#, 2# and 11# were 130 m, the depth of wells 3#, 4# and 7# were about 125 m, and the depths of wells 5#, 6#, 8#, 9#, 10#, 12# were about 120 m. The groundwater samples were collected on April 16, 2015. A total of 27 indexes were determined including pH value, chloride, sulfide, nitrate nitrogen, ammonia nitrogen, heavy metals, fluoride, and so on. In the single factor evaluation, the groundwater quality was evaluated according to the National Groundwater Quality Standards (GB/T14848-93). Based on the single factor evaluation method, water quality in 5 wells of 1#, 4#, 7#, 9# and 11# exceeded the standards. In the 1# well, the turbidity, total hardness, total dissolved solids and nitrate nitrogen exceeded the standards by 1.67, 1.81, 1.48, and 3.08 times, respectively. In the 4# well, the turbidity was 1.33 times exceeding the standard. In the 7# well, the total hardness and total dissolved solids exceeded the standards by 1.2 and 1.15 times, respectively. In the 9# well, the fluoride exceeded the standard by 1.58 times. The ammonia nitrogen in the 11# well exceeded the standard by 3.25 times. Compared the values in 1999, the area with total hardness exceeding the standard was expanded largely. Among the 27 indexes, we chose 17 indexes for the comprehensive evaluation based on BP neural network, including the turbidity, iron, chloride, sulfate, TDS, total hardness, manganese, zinc, potassium permanganate index, nitrate nitrogen, nitrite nitrogen, ammonia nitrogen, fluoride, and so on. The BP evaluation showed that all the 12 wells had the water quality above III. Among the wells, 1 was V grade, 5 were IV grade and 6 were III grade. Compared with the single evaluation results, the comprehensive evaluation based on BP neural network was reasonable. The 1# well had 4 indexes exceeding the standards and thus the water quality was V grade. Compared with previous study, the pollution of nitrate and ammonia nitrogen might be due to surface pollutants infiltration. In the future, the continuous monitoring of shallow groundwater should be conducted, and the surface pollutants infiltration prevention control should be strengthened. The study may provide valuable information for the management of the groundwater in Beijing. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Vegetation types affect process of runoff, soil erosion and nutrient transport along loess slope land. In order to clarify the influence of vegetation types on surface runoff, sediment transport and nutrients in loess region, a field water scouring experiment was performed on a natural, fallowed loessial slope (38°46′-38°51′N, 110°21′-110°23′E) on 14 km west of Shenmu Erosion and Environment Research Station of Institute of Soil and Water Conservation, Chinese Academy of Sciences, in the Liudaogou watershed, Shenmu County, Shaanxi Province at Shenmu. A steady-head water scouring method was adopted under natural conditions. Field plots were established on a slope that had been fallowed for 7 years. Herbaceous and crops were selected as vegetation types, including maize, millet, soybean, cymbaria dahurica, alfalfa and caragana. Runoff, sediment, and nutrients (nitrogen and phosphorus) under different vegetation cover were determined. In addition, basic growth characteristics of various vegetations in each plot were measured. Results showed that compared with the other vegetations, the effect of herbaceous (cymbaria dahurica) on the decrease of surface runoff was largest, and soybean was the lowest. With vegetation cover, less sediment was carried with by runoff, the process of sediment appeared a peak for all the vegetation cover, and alfafa cover significantly decreased sediment loss. Under different vegetation covers, the concentration of nitrate nitrogen and soluble phosphorus in runoff water decreased rapidly at the initial runoff stage, and then to be stabilized. The process of nutrients (nitrate nitrogen and soluble phosphorus) transport could be better described with power function than exponential function. Results also revealed that the amount of nitrate nitrogen in sediment decreased rapidly, while the amount of effective phosphorus in soil reduced gradually over time. When soil surface was covered with alfalfa, and the total loss of nitrate nitrogen and phosphorus in sediment was highest. It could also be found that nutrients enrichment ratio had a reverse relationship with erosion amount for the all vegetation cover. The total loss of nitrate nitrogen under different vegetation cover was highest in millet cover, followed by alfalfa, caragana, maize, soybean, and cymbaria dahurica, and the total loss of soluble phosphorus was highest in millet cover, followed by maize, caragana, soybean, cymbaria dahurica and alfalfa. Nitrate nitrogen showed a peak feature along depth in soil profile, and the peak position was different for different vegetation covers. Phosphorus was mainly cumulated at the top 5 cm of the surface layer, and the amount of phosphorus was extremely low below 5-cm soil depth. In conclusion, the effects of herbaceous cover on surface runoff, sediment transport and the loss of nutrients were much better than crop cover. This study provides a way for further analyzing the effect of vegetation cover on water and soil nutrient loss, and provides a guide for controlling soil water loss and agricultural management. [ABSTRACT FROM AUTHOR]

The application of activated brackish water in the water treatment and agriculture fields has been getting a lot of attention. The activated brackish water usually has different impact on the growth of plant, and a reasonable index is necessary for evaluating the effects of different activated brackish water. In this paper, a laboratory experiment was carried out to investigate the physical and chemical characteristics of the NaCl brackish water, which were set as different salinity (0.1, 1, 2, 3 and 5 g/L). The magnetized and ionized methods were adopted to activate the brackish water, and the technical requirements of the ionized activation system of brackish water were ascertained. Meanwhile, the changes of surface tension coefficient, dissolved oxygen, electrical conductivity and pH value of activated brackish water were studied by the laboratory test. The results indicated that there were stable grounding current and activation effects, when the grounding resistance was less than 5 Ω. Furthermore, the changes of the physical and chemical characteristics of the activated brackish water were extremely remarkable. The surface tension coefficient reduced significantly, while the change of dissolved oxygen was opposite. In the meantime, the electrical conductivity and pH value were affected at different degrees. With the increase of brackish water salinity, the surface tension coefficient increased accordingly, while the dissolved oxygen changed oppositely. The surface tension of the activated brackish water relatively reduced by 9.14%-13.84% in the brackish water with the salinity of 5 g/L, while the dissolved oxygen relatively increased by 8.04%-10.23%. According to the surface tension′s relative reduction, the difference was obvious among different activated treatments. The ionized activation treatment was superior to the magnetized water, and the stainless steel ionized separator (SIW) was better than the one with magnesium core(MIW). There was the optimum magnetization for permanent magnet, and the surface tension′s relative reduction had the maximum value under the magnetic field strength of 3 000 Gs. The variable frequency (VF) magnetized brackish water treatment was stable, but still less than the optimum magnetization. On the basis of the value of dissolved oxygen relative increment, the distinction was also significant among different activated treatments. The value of oxygen relative increment had the maximum value under the magnetic field strength of 3 000 Gs. When the salinity exceeded 3.0 g/L, the effect was greatly reduced. Foremost, there existed a significant index function relationship between the relative reduction of surface tension and the relative increment of dissolved oxygen(R2>0.88, P<0.05). The relationship could be used to estimate the corresponding relative increment of dissolved oxygen, when the relative reduction of surface tension was known. In conclusion, the surface tension′s relative reduction can be used to quantitatively evaluate the changes of the physical and chemical characteristics of the activated brackish water. This study may provide valuable information for the application of activated brackish water in agriculture irrigation. [ABSTRACT FROM AUTHOR]

Soil physical basic parameters are key factors for impacting the soil thermal conductivity, and they are also closely related to the model parameters used to calculate the soil thermal conductivity. In order to study the relationship between soil physical basic parameters, organic matter content and soil thermal conductivity model parameters, the precision of different soil thermal conductivity models was discussed by analyzing 10 types of soil samples in this paper. There were 9 types of soil textures which were sampled from different areas in Shaanxi Province, and the last one was sampled from Zhangye, Gansu Province, which was used to verify the feasibility of the new models. According to the sand content, these soil samples were divided into 2 types: fine-textured soil and coarse-textured soil. The soil thermal conductivity models were used to fit these 2 types of soils, and the comparison results indicated that the theoretical models such as Côté-Konrad model and Lu-Ren model were more precise than Campbell model and Johansen model. The fitted results of Johansen model were significantly smaller than the measured values, and the ranges of root mean square error (RMSE), coefficient of determination (R2) and relative error (Re) for this model were 0.0848-0.2548, 0.656-0.827 and 10.32%-20.41%, respectively. Moreover, Côté-Konrad model and Lu-Ren model had better fitting results for fine-textured soil, and the ranges of RMSE, R2 and Re were 0.0810-0.1208, 0.842-0.940 and 9.67%-10.57% for Côté-Konrad model and 0.0725-0.1238, 0.874-0.937 and 8.28%-9.91% for Lu-Ren model. However, these 2 models were not suitable for calculating the soil thermal conductivity of coarse-textured soil when the water saturation was larger than 50%. Thus, the improved models, which described the relationship between thermal conductivity and soil physical basic parameters, were developed based on Côté-Konrad model and Lu-Ren model. The results showed that the improved models could be used to fit the thermal conductivity in different soil textures, and the RMSE was less than 0.0964, the R2 was up to 0.92 and the Re was less than 9.6%. For predicting the soil thermal conductivity with higher sand content or higher silt content, the values of RMSE, R2 and Re for the improved Côté-Konrad model were 0.1183, 0.9259 and 9.47%, respectively, which was better than the Côté-Konrad model, Lu-Ren model, and improved Lu-Ren model through the analysis of simulation error. On the other hand, for predicting the soil thermal conductivity with lower sand and silt contents, the values of RMSE, R2 and Re for the improved Lu-Ren model were 0.0815, 0.9326 and 8.11%, respectively, which was better than the other 3 models. Moreover, the improved models were used to calculate the soil thermal conductivity of the other types of soil textures in Zhangye. Because the soil texture in Zhangye is sandy clay loam soil in which the sand content is higher than 60%, the improved Côté-Konrad model has the best effect when calculating the soil thermal conductivity according to the analysis results. The parameters in the improved models contain soil texture and organic matter content, which can be used to describe the relationship between thermal conductivity and soil physical basic parameters in detail. Furthermore, choosing an appropriate improved model based on soil texture can calculate the soil thermal conductivity more accurately. [ABSTRACT FROM AUTHOR]

Due to low rainfall, intense runoff, deep loess deposits, low water tables as well as poor land management, soil is often dry on the Loess Plateau. Precipitation is very important for crops, especially the winter wheat. However, it is unknown about the impacts of rainfall in summer fallow period on soil water replenishment and growth of following crops. To clarify this problem, this study carried out field experiments from 2006 to 2010 in Changwu city of Shanxi province. Winter wheat was Chanhan 58. The field plots were 4 m in width and 4 m in length. 6 irrigation treatments were designed including 0, 75, 150, 225, 300 and 375 mm and 6 N fertilization rates were used including 0, 75, 150, 225, 300 and 375 kg/hm2. A total of 27 irrigation-fertilizer coupling treatments were designed. Each treatment had 4 replications. Meteorology data were collected from meteorological station 100 m away from the experimental field. Soil water content was measured after harvest and before sowing of winter wheat. Yield and its component of winter wheat were measured. The results showed that the amount of soil water recharge was significantly affected by the precipitation in summer fallow period (P<0.01). Different irrigation and N fertilizer coupling treatments had great effects on the recharge of soil water in summer fallow period of winter wheat (P<0.05). The coefficient of soil water recharge decreased with the increase of fertilizer application rate and then increased and finally decreased under the irrigation treatments of 0, 225, and 375 mm. At same time soil water recharge coefficient for the treatment of N fertilizer application rate of 225 kg/hm2 was highest. In the same way, it presented a decrease-increase-decrease trend when N fertilizer application changed from 0, 150, to 375 kg/hm2, and the soil water recharge coefficient was highest for the irrigation treatment of 225 mm. The deficit of soil water was exponentially related with soil water recharge, and soil water recharge coefficient was best when the water deficit was 43.68%-52.63%. The soil water recharge coefficient and the contribution rate of soil water recharge coefficient to water consumption of winter wheat were in a relationship of power function. The effect of water supplement to soils was best when the coefficient of soil water recharge was 52.2%-62.4%. The power function was also found between the soil water recharge coefficient and indicators such as yield, spikelet number, spike grain number and thousand seed weight of winter wheat in the following year. Different from the positive relationships between the others and the soil water recharge coefficient, a negative correlation was observed between thousand seed weight and the soil water recharge coefficient. As the soil water recharge coefficient ranged from 25% to 40%, the variation of yield, spikelet number, spike grain number and thousand seed weight was minimal, and this was good for use of precipitation during summer fallow period to increase water use efficiency and yield of winter wheat. The results lay the foundation of soil water and agriculture management, and guide farmers to irrigate with high efficiency for high crop yield. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)