The use of nitrogen fertilizer on saline alkali soil should not only focus on economic benefits，but also the effect of nitrogen fertilizer on saline alkali soil． In order to study the infiltration parameters between nitrogen application and saline alkali soil，a 1D vertical saline soil column infiltration test is conducted with different nitrogen application ( 0，300，600，900 mg /L) and different soil salt content ( 0．3%，0．9%， 1．2%) ． The results show that nitrogen application on the saline alkali soil reduces the infiltration; with the increase of nitrogen application， the infiltration parameters trend of 0．3% and 0．9% saline alkali soil is up－down－up; when nitrogen application is 600 mg /L，the infiltration property is the best，too high or too low nitrogen application will lower the infiltration property of alkaline soil; with the same nitrogen application，the soil infiltration property of salt content 0．3% is the best，and the soil infiltration property of salt content 1．2% is the worst． The research results can provide guidance for rational nitrogen application based on the conditions of crop growth in saline alkali soil of Xinjiang

Under the premise of micro－wetting irrigation，in order to explore the effects of different irrigation methods on the growth and development of greenhouse peppers，this experiment set up 4 different treatments，including alternate irrigation ( A treatment) ，intermittent irrigation ( B treatment) and continuous irrigation ( C treatment) and general irrigation ( D treatment) and each treatment was repeated 3 times to analyze the growth status and irrigation water utilization efficiency of pepper． The results showed that the plant growth and yield of the mild irrigation treatment group were higher than that of the general irrigation group，and the irrigation water productivity was 2．23 times，3．08 times and 2．97 times of that of the general irrigation group． The irrigation water productivity of the intermittent irrigation was the highest

Using“Jingxiu”watermelon as the test material，based on the weighing lysimeter，the evapotranspiration law of the autumn mini －watermelon in the greenhouse and its correlation with the environmental factors were studied． The aim was to provide the basis for precision irrigation of greenhouse autumn watermelon． The results show that the evapotranspiration of mini－watermelon is 114．79 mm in the whole growth period，and the average daily evapotranspiration is 1．11 mm/d． The autumn mini－watermelon in the greenhouse shows a small change in the early stage，medium to large stage，and late stage． Among them，the daily evapotranspiration at the seedling stage，vine extension stage，flowering fruit setting stage，fruit expansion stage and maturity stage are 1．04，1．20，1．34，1．08，0．81 mm/d，respectively． The environmental factors significantly affect the change of evapotranspiration of the watermelon in the autumn harvest． Photosynthetically active radiation，solar radiation，saturation difference，maximum temperature，average temperature，and minimum temperature are all significantly positively correlated with the daily evapotranspiration of watermelon． The correlation coefficients are 0．813，0．777，0．742，0．618，0．434，and 0．290，respectively． The relative humidity is significantly negatively correlated with the daily evapotranspiration of watermelon，with a correlation coefficient of －0．517． An empirical model for the daily evapotranspiration of watermelon seeds based on photosynthetically active radiation，solar radiation，and relative humidity is established． After an Ｒ2 of 0．706 is verified，the daily evapotranspiration of the autumn mini－watermelon in the greenhouse can be estimated．

In order to study the effects of soil catalase activity (CAT) and tomato growth on soil CO2 emission under the condition of aerated irrigation, an experiment was conducted by using the static closed chamber/gas chromatography method from April to July, 2017. The experiment adopted two treatments: aerated irrigation (AI) and traditional subsurface drip irrigation (CK). Soil CO2 flux, CAT, soil water-filled pore space (WFPS), soil temperature and plant height of tomato were measured simultaneously. The results indicated that throughout the whole growth stage of tomato, soil CO2 fluxes showed a first increasing then decreasing under the two treatments, and soil catalase activity presented a fluctuating change and reached the maximum value at the end of tomato growing period. Compared to CK, AI increased cumulative soil CO2 emissions by 2.4%, but the treatment effect was not significant (P>0.05). AI promoted tomato growth, increased CAT and soil temperature, while decreased WFPS, but the differences between the two treatments did not reach a significant level (P>0.05). Positive correlations between soil CO2 fluxes with CAT, soil temperature and plant height were observed (P>0.05). Significant negative relationships among soil CO2 fluxes and WFPS were reported (P<0.01)

In this paper，the packaged stem sap flow gauge was used to continually measure the sap flow dynamics of citrus trees． The meteorological factors，including net solar radiation，ambient temperature and relative humidity，were detected at the same time． The correlation between the transpiration rate and meteorological factors were analyzed． The results showed that the transpiration curve of citrus trees was bimodal type; the transpiration rate of potted citrus trees was positively correlated with net solar radiation and ambient temperature， and negatively correlated with environmental relative humidity; the absolute values of the correlation coefficients of all the meteorological factors from large to small were ranged as ambient temperature ( 0．849) ，net solar radiation ( 0．813) ，relative humidity ( －0．810) ，the wind speed ( 0．570) and dew point ( 0．219) ，and ambient temperature was the dominant environmental factor． Then an empirical regression model was established by using the three main environmental factors described above，the simulation results of empirical models was more accurate than that of the PM model． The empirical models can be used to predict the water consumption by transpiration of citrus trees in the Yichang area．

In order to provide theoretical support for the sand-mixing system of water storage and fertilizer conservation in arid and semi-arid areas, the experiment used artificial simulation of rainfall indoor to study the effects of sand mixed rate on soil water infiltration and redistribution under inadequate water supply. The soil cylinder incubation treatments were setup including 0 (Control), 25%, 50%, 75% of sand mixing rate. Research indicates: (1)The treatment of sand mixed can speed up the process of wet front movement. The higher the sand mixed rate, the more obvious the effect, and the greater the effect when the sand mixed rate is more than 25%.(2) The higher the sand mixed rate, the smaller the water content in the soil of sand mixed, The greater the water content and the better the water retention below the soil of sand mixed. Sand mixing rate of more than 50% can achieve better water retention .When the sand mixing rate is 75%, the soil moisture content at the depth of 30 cm is increased by about 40% compared with the soil without sand mixing. (3) When the sand mixed rate is 75%, the soil moisture content is the highest at 15 cm depth, and the soil moisture retention is the best at 30 cm depth during the redistribution phase. So when the sand mixed with a higher rate, the best aquifer is 15 ~ 30 cm. It provides continuous water supply for plant growth.

Under the fertigation cultivation mode of drip irrigation in Yellow Ｒiver irrigated area in Gansu，the yield performance，water use efficiency and production benefits of seed corn were studied． The results show that suitable irrigation quota and fertilizer application are beneficial for increasing yield，the yield of seed corn decreases when the irrigation water is shortage，and the effect of increasing yield is not significant when the fertilizer is applied too much． Under the condition of 3 450 m3 /hm2 irrigation water quota with fertilizer quantity of 270 kg / hm2 N，90 kg /hm2 P2O5 and 54 kg /hm2 K2O，compared with other treatments，the yield of seed corn is increased by 1 395．5～3 600．0 kg /hm2 ， the water use efficiency is improved by 1．13～9．38 kg /( mm·hm2 ) ，the net income of planting is increased by 7 779．0～2 1920．0 yuan /hm2 ， and the ratio of output to investment is increased by 0．09～1．41．The effects of water and fertilizer usage and planting benefit are optimized．

Abstract：In order to further explore the influence of different coating widths on soil moisture and soil temperature of cotton, the soil temperature at 0-25cm and the soil moisture at 0-100cm were measured for the two growing widths of cotton. The results show that the super wide film (2.05m) is narrow (1.4m) effect is more significant; the trend of the diurnal variation of soil temperature under the condition of different width of film is similar to that of the 5cm soil surface temperature was affected by atmospheric temperature, and lag effect weakened with the increase in soil depth. At the late growth stage of cotton, the average temperature of 5-25cm soil was very narrow and the membrane width was 0.1-1.1. Soil moisture content is negatively correlated with soil temperature at different growth stages of 25cm, and when soil moisture content is low, soil temperature is high, under the condition of super wide membrane, the correlation was higher than that of the narrow membrane. The super wide membrane mulching improved the water and heat conditions of the soil, and accelerated the growth and development of crops. For the cotton planting in the North Xinjiang, the use of super wide film mulching has a yield increase of 13.7% per hectare. The research results can provide a scientific basis for cotton production in North Xinjiang.

In order to explore the effect of the technology of drip irrigation with trenching and coating on soil temperature change during grape growth period，this paper analyzes the temperature variation of 0 ～ 100 cm soil layer inside and outside the membrane under different drip irrigation water volume and different trenching modes according to the field experiment conducted in 2016． The variance analysis method is used to compare the significant differences in temperature between the soil layers inside and outside the membrane under different irrigation volumes and different trenching modes． The results show that the fluctuation trend of temperature of each soil layer is consistent with the trend of atmospheric temperature，and the influence of atmospheric temperature is weakened with the increase of soil depth，regardless of whether the soil temperature in the membrane or the soil temperature outside the membrane is between 14 ℃ and 33 ℃ ． Through variance analysis， it is found that the effect of drip irrigation on the temperature of 0 ～ 60 cm in the membrane and 0 ～ 40 cm in the membrane is significant． Compared with the low－irrigation treatment，the high－irrigation treatment reduces the soil temperature of the 0 ～ 20 cm soil layer in the membrane by 2．9 ℃，and increases the soil temperature of the 20～ 40 cm and 40～ 60 cm soil layers in the membrane by 1．8 ℃ and 0．36 ℃， respectively． Outside the membrane，compared with low － irrigation treatment，the medium and high irrigation treatments increase the temperature of 0～ 20 cm soil layer by 0．95 ℃ and 1．26 ℃，respectively，and increase the soil temperature of 20～ 40 cm soil layer by about 1 ℃ ． The effect of the trenching mode on the temperature inside the membrane and the temperature outside the membrane is not significant． Appropriately increasing the width of the trench can slightly increase the soil temperature inside and outside the membrane．

In order to make use of the abundant brackish water underground reasonably in gravel－mulched field area of Ningxia，taking the NO．5 Cerasus humilis as the test material，the influences on photosynthesis and yield were studied through the brackish water irrigation test with 2．35 and 4．07 g /L mineralization degree． The results show that: the photosynthesis and yield of the 2．35 g /L treatment is superior to that of the 4．07 g /L treatment，but the fruit quality of the 4．07 g /L treatment is better; there is no significant difference of SPAD，single fruit weight，yield per mu and irrigation water use efficiency of Cerasus humilis between the 2．35 g /L brackish water irrigation treatment and the fresh water treatment，while the fruit quality irrigated by 4．07 g /L brackish water is remarkable superior to that irrigated by fresh water． Considering all indexes，it can be concluded that the 2．35 g /L salinity is the suitable salinity for local brackish water irrigation，at the same time，it is also feasible to use the local 4．07 g /L brackish water as irrigation water．

In order to analyze the influence of different salinity and dripper flow on soil wetting body，the experiments of drip irrigation under the conditions of different salinity ( 0，1．7，3，4，5 g /L) and different dripper flow ( 7，9，11 mL/min) were carried out in this paper． The results show that the wetting front of drip irrigation with different emitter discharge and different brackish water salinity is similar in shape， which is 1 /4 ellipse，and the wetting front increases with time; the greater the emitter discharge，the quicker the horizontal wetting front advances; with the increase of salinity，the maximum advancing distance of the horizontal wetting front decreases first and then increases， and the maximum advancing distance of the vertical wetting front increases first and then decreases; the wetting front of soil with different salinity and dripper flow can be fitted with elliptical equation． On the basis of analyzing the influence of salinity，dropper flow and time on the parameters A and B，the dynamic change model of soil wetting front in drip irrigation under the coupling condition of salty water salinity and dripper flow is established． Then the experimental data are used to verify the results． The results show that the MAE and ＲMSE of the training set model are 0． 390 and 0． 549，respectively; the MAE and ＲMSE of the validation set model are 0． 438 and 0． 635，respectively． This indicates that the model has higher calculation accuracy and can be used for the dynamic simulation of drip irrigation soil wetting under the coupling of brackish water salinity and dripper flow．

Accurate assessment of reference crop evapotranspiration (ET0) in Southwest China is of great significance for crop water consumption analysis, crop productivity potential assessment and regional water resources management. This paper applies the meteorological data in the Southwest of China for nearly 56 years, the ET0 in Southwest China is calculated by FAO-56 Penman-Monteith model. The characteristics and trends of ET0 and associated meteorological factors in the Southwest of China for nearly 56 years were analyzed by Mann-Kendall detection, change trend analysis and contribution rate based on the sensitivity coefficient. The results show that the values of ET0 in spring, summer, autumn and winter in the Southwest of China in the past 56 years are 314.71mm, 345.78mm, 219.13mm and 169.51mm respectively; The climatic tendency was 0.850mm/(10a), -2.841mm/(10a), 0.571mm/(10a) and 1.125mm/(10a), in which the spring and autumn ET0 showed no significant trend, and the ET0 showed a very significant downward trend in summer (P<0.01), and a significant upward trend in winter (P<0.01). The relative humidity, sunshine duration and wind speed showed a downward trend in the four seasons, and the temperature showed an upward trend, in which the relative humidity showed a very significant downward trend (P<0.01), and the minimum temperature showed a very significant upward trend (P<0.01). In spring, relative humidity contributed the most to ET0, which was 5.23%; in summer, sunshine duration contributed the most to ET0, which was -7.49%; in autumn, the maximum temperature contributed the most to ET0, which was 3.94%; The minimum temperature in winter contributed the most to ET0, which was 6.69%, followed by the average temperature of 6.57%. Therefore, in the past 56 years, the main reasons for the rise of ET0 in spring, autumn and winter in the Southwest of China are lower relative humidity, higher maximum temperature, higher minimum temperature and higher average temperature, respectively; The main reason for the decline of ET0 in summer is the reduction of sunshine duration.

In order to evaluate and analyze the water quality of Yiyuan County，24 indexes，including fluoride，iodide，manganese and plumbum，in the water quality data of 15 monitoring points in Yiyuan county were selected，and the water quality evaluation and comparison are conducted by the improved fuzzy comprehensive evaluation method and Nemero index method． The results of the improved fuzzy comprehensive evaluation consider the degree of membership of different factors in different water quality categories． On this basis，the results are improved in algorithm to ensure that the results are continuous． The improved Nemero index method considers the effect of the maximum value on the overall water quality，and the weight factor is added to balance the results． There is an obvious change． The trend of water quality evaluation of Yiyuan County in wet season is basically the same as that in dry season． The main factors affecting the groundwater quality in Yiyuan County are summarized by principal component analysis，which are mainly the influence of the elements contained in the formation， the excessive use of artificial pesticides and chemical fertilizers，the improper treatment of animal manure，the improper discharge of factory waste water and dust，and so on． The water rock interaction in the study area is mainly the dissolution and sedimentation，and a few mixed effects．

As the center of the Beijing －Tianjin economic belt，Tongzhou district is an important food and vegetable production basis in Beijing． The groundwater is the main source of cultivation and drinking water for residents and animals． It is significant to study the distribution characteristics and formation causes of groundwater in Tongzhou for rational development and protection of groundwater resources and playing the role of satellite cities． Based on field sampling and testing，this paper systematically studied the hydrochemical characteristics and genesis of shallow groundwater in Tongzhou by using Shukalev classification，Piper diagram，contour map and ion ration analysis． The methods of comprehensive appraisal and Nemero index were used to assess the quality of phreatic water． The results show that : ①The phreatic water presents medium－weak alkalinity，hydrochemical characteristic is mainly HCO3－Ca·Mg( HCO3－Ca·Na or HCO3－Ca·Mg ·Na) and HCO3·Cl－Mg·Na( HCO3·Cl－Na·Ca) ，and the phreatic water is mainly of freshwater with TDS between 0．5 and 1．0 g /L． ② Chemical composition of phreatic water is affected by lithology，topography，climate and human activity． ③The phreatic water quality is mainly at Grade Ⅲ in Tongzhou by mapping the groundwater quality assessment zone，and the main pollutants are NH4－N，NO3－N，F and As

The evaluation of the regional water saving irrigation development level is a multi － level，multi － index and multi － factor comprehensive process． The multi － index comprehensive evaluation is to consider several multiple indexes of information reflecting the research object of different properties and get the evaluation results，hence to reflect the whole situation of the evaluation objects． The research establishes an evaluation model based on the technique for order preference by similarity to ideal solution，builds the comprehensive evaluation index system of water saving irrigation development level at Fen river basin，determines the project indicators，selects a single index which belongs to the special index，and determines the individual index weight based on the entropy method and analytic hierarchy process． According to the calculation of the decision matrix calculation，the relative closeness coefficient，namely the evaluation grade standard，is obtained and the evaluation results is made． The results show that the calculation model is stable and reliable and the development level of water saving irrigation is at a low level．

Based on the microscopic data of farmers in Xinjiang,this paper constructs two classified regression model,and explores the main factors affecting the structural imbalance of agricultural water-saving irrigation technology from 5 dimensions of cotton farmers' characteristics,family endowment, geographical features,social relations and technical information acquisition.The results show that the service content,supply service subject and channel of agricultural water-saving irrigation technology in cotton-planting regions are unbalanced,and the factors that influence the structural imbalance of supply and demand are different,and whether there are any information service associations have significant influence on them.In view of this, it is necessary to improve agricultural technology Service system,innovative service mode to alleviate the imbalance of agriculture water-saving irrigation Technical Service.

Groundwater depth prediction plays an important role in agricultural production, rational utilization of land and water resources, and ecological environment protection. Groundwater depth is a multi-level complex system, which is influenced by many factors, further more, the groundwater’s evolution has the characteristics of uncertain, random, fuzzy and unstable. Based on the strong ability of EEMD to deal with nonlinear problem and the Elman network has the advantages of adaptive time and dynamic memory, a groundwater prediction coupling model based on EEMD and the Elman neural network is proposed, and applied to groundwater depth prediction in people’s victory canal irrigation district. The results show that the maximum relative error, the minimum relative error and the qualified rate are 2.91%, 0.04% and 100%, respectively, and the prediction accuracy of the coupling model is much higher than single BP model and Elman model. In addition, to some extent, the model can reveal the evolution mechanism and factors of groundwater time series, further more, the model is simple in calculation and clear in thinking, which provides a new way for groundwater depth prediction.

The construction of water－measuring devices in large and medium－sized irrigation areas is an important part of the comprehensive reform of agricultural water price． The setting principle of water － measuring devices and the arrangement of the water － measuring points directly affect the cost and efficiency of water metering in the irrigation area． In many large and medium－sized irrigation areas along the Beijing－Hangzhou Grand Canal，the irrigation areas along the Li Canal in Jiangsu Province were selected to study． The measurement and water demand were analyzed，and the setting principles of water－measuring devices were put forward． The Gaoyou irrigation area of national large irrigation area was taken as an example to give evidence，and the relevant suggestions on water－measuring devices were put forward．

Normalized Difference Vegetation Index ( NDVI) is an important tool for assessing crop growth condition and has been widely used in agriculture field． It is a vegetation index based on the high absorption rate of red light and high reflectance of near－infrared light． And it has been found to be dynamic at different times in a day because of crop itself and environmental factors，so the accurate determination of NDVI is difficult． To explore daily changes of NDVI at main growth stages of winter wheat，the winter wheat canopy reflectances in the 656 and 770 nm wavelengths were obtained by Greenseeker to compute NDVI． The data were obtained in successive hours at reviving stage， jointing stage，and heading stage，respectively． The study proves that the winter wheat canopy NDVI values are dynamic in different periods of a day; the NDVI data demonstrates clear parabolic shaped diurnal variations; it decreases gradually from 8 ∶ 00AM，and reaches to its minimum at 13 ∶ 00PM or 14 ∶ 00PM followed by a rapid increase in the afternoon． In order to describe the variations of the daily NDVI values，the quadratic polynomial regression，Gauss function and Sine function was used to fit the normalized NDVI daily variation curve respectively． Before fitting，a normalization processing for the original data was made to limit the data in the same range，which was convenient for the compare of different models． In significance test，the selected models were all statistically significant ( P＜0．01) in the three growing stages of winter wheat． And the three models had the best fitting effect in the jointing period with the coefficient of determination ( Ｒ2 ) all above 0．9． But the quadratic polynomial model expressed better stability than the other two models． Then the predicted and measured values were compared and the best fitting model was found by root mean square error ( ＲMSE) and mean absolute error( MAE) ． The results show that all three models have good fitting effects，however，the prediction precision of quadratic polynomial model is the best with the ＲMSE of 0．212，0．213 and 0．187，and MAE of 0．165，0．162 and 0．142 in the three stages of reviving，jointing and heading，and the other two models show almost the same prediction accuracy． This study can provide a reference for the future study of the NDVI daily change process and NDVI accurate monitoring of winter wheat．

In order to determine the effect of increased production of peanut covered with plastic film in the Guanzhong area and the appropriate amount of nitrogen applied to peanuts under plastic film，the two ways of none coating with film ( W0) and coating with film ( W1) were set and combined with six nitrogen application rates，including N0 ( 0 kg /hm2 ) ，N2 ( 60 kg /hm2 ) ，N4 ( 120 kg /hm2 ) ，N6 ( 180 kg /hm2 ) ，N8 ( 240 kg /hm2 ) ，and N10 ( 300 kg /hm2 ) ． The above－ground dry matter accumulation，agronomic traits，yield，water consumption，and water use efficiency of peanuts under different filming conditions were studied． The results show that the treatment with the film ( W1) has significantly higher production than that with the non－film ( W0) treated peanuts，and the yield is increased by 17．3% to 24．8% under different nitrogen application rates; at the same time，the water use efficiency of the peanuts can also be improved about 16．1% ～ 22．9%． In addition，the peanut yield，water use efficiency，and nitrogen application rate show a significant parabolic trend; at the nitrogen application level of N0～N4，it increases first with the increase of nitrogen application rate，while for N6～N10，it decreases with the increase of nitrogen application rate; at the level of nitrogen application N4，both reach the maximum． Therefore，when the amount of nitrogen applied under the covered with film conditions is 120 kg /hm2 ，the W1N4 treatment in this experiment is a suitable planting and nitrogen application strategy for peanuts in the Guanzhong area． Compared with the W0N0 treatment，the yield and water use efficiency is increased the most， 47．2% and 47．8%，respectively

According to the fact that a large number of old irrigation districts in China still cannot equipped with fixed water flow metering facilities at present, this paper suggests the storage capacity method to measure the water intake in the irrigation area. The differences of water volume between the storage capacity method and the trapezoid thin-plate weir method as well as the electromagnetic flowmeter method were compared in the U-type anti-seepage canal, rectangular-type anti-seepage canal, trapezoid-type anti-seepage canal and trapezoidal soil canal. The results showed that there was no significant difference in water volume in the storage capacity method compared with the other two methods, and the water volume of the pumping stations measured by the U-type anti-seepage canals, rectangular-type anti-seepage canals, trapezoid-type anti-seepage canals and trapezoidal soil canals were 0.146 to 0.164m3·s-1, 0.105 to 0.121m3·s-1, 0.124 to 0.142m3·s-1 and 0.083 to 0.101m3·s-1, respectively. And the deviation were -2.77% ~ -2.79%, 0.49% ~ -0.72%, -3.90% ~ -2.46% and -5.42% ~ -6.31%, respectively, and the relative deviation were all lower than that of the field test, which was 0.19% ~ 1.48%.As a water volume measurement technology, the storage capacity method is convenient and reliable and may be used in irrigation area widely.

There exist some problems in mountain orchard irrigation systems，such as small action scope，large number of relay nodes，high deployment costs，and so on． This paper designs a mountain orchard irrigation system based on LOＲA communication． The proposed system uses the information collection terminal node to collect the soil moisture content of the orchard in real time，the LOＲA wireless communication network is used to send the soil information to the routing and control module in the mountain communication control node， and the wireless packet network ( GPＲS) is used to transmit the processed data packets to the cloud server． Finally，the information in the cloud server is displayed by different clients to realize human－computer interaction． The results demonstrate that the system can cover more than 92% of the communication area of a mountain orchard with an area of 20 hectares in direct connection mode． Compared with the ZigBee communication method，the system saves a large number of relay nodes． Because of its long－distance communication characteristics，the communication node can be arranged with more possibilities．