AquaCrop model, with semi-quantitative method instead of specific fertilization, can effectively reduce the simulation errors caused by the spatial variability of regional fertilization management combining with remote sensing data. AquaCrop model was calibrated and validated using field measurements of 2012 and 2013 and the simulation accuracy was analyzed. Results showed that R2 of the simulated and observed values of soil water content reached 0.83 and 0.89, respectively, and that of the canopy coverage were both greater than 0.90. RMSE of the canopy coverage reached 7.50 and 7.90, respectively. In 2012, R2 of the simulated and observed values of above ground biomass reached 0.97, and 0.74 in 2013. The semi-quantitative method of the model was further used to simulate the growth indexes of crop, and the coefficients related to fertilizer stress under different fertilization levels were quantified, which lays foundation for the regional application of the model.

The effects of drought stress on maize growth and development and its response to drought stress were studied based on the special test data of maize under drought stress in Xinmaqiao agricultural water comprehensive test station in Anhui province． The results showed that drought affected various indexes of maize photosynthesis，and the change of photosynthesis affected the growth and development of maize plant height and leaf area． In the early and middle stage of maize nutritional growth，the crops were in the rapid growth stage and had stronger adaptive function to water stress． After the relieving of moderate and slight drought stress，maize could quickly return to normal growth，and its subsequent growth and development would be better than that of crops without drought stress． Under the same degree of drought stress，the response of later vegetative growth stage and reproductive growth stage of maize was more sensitive to water deficit，which was more likely to cause permanent damage to maize plants and lead to yield reduction． In order to improve the water utilization rate of maize during the whole growth period，achieve efficient water saving and ensure stable yield，this paper proposes that inadequate irrigation can be implemented for moderate water shortage in the early stage of maize vegetative growth，while adequate irrigation should be implemented in the later stage of vegetative growth and reproductive growth．

This paper is aimed at achieving the comprehensive evaluation of soil nutrient under drip irrigation.By using descriptive statistical analysis, Principal Component Analysis (PCA) and BP neural network, the soil nutrient with drip irrigation under mulch was evaluated in Kezuo Zhongqi,Tongliao which were combined with single factor evaluation and compared with the most widely used fuzzy mathematics comprehensive evaluation results in traditional methods.According to the second national soil nutrient grading standard and verified by measured data,the results show that the comprehensive evaluation level of soil nutrient with drip irrigation under mulch in Kezuo Zhongqi in 2015 and 2016 is Relatively good,and we can get more objective results which are more suitable for the actual situation by connecting PCA and BP neural network in the aspect of evaluating level of soil nutrient.It’s feasible and reliable to solve the soil science problem by connecting PCA and BP neural network according to the comprehensive study of many experts’ achievements.The evaluation method of combining PCA with BP artificial neural network model is suitable for the samples with many factors and high complexity and high precision.Combining PCA with BP neural network can not only solve the problem of too much information and difficulty in analyzing but also reduce the fuzziness and the precision declining.It link the respective advantages effectively. Compared with the traditional method it can be more scientific and reasonable, accurate and effective to comprehensive evaluate the soil nutrients.

In order to meet the needs of fertigation and multi － nutrition allocation，this paper designed a simple 3 － channel fertilizer applicator． By means of experiment，the influence law of inlet pressure，flow rate and opening number of fertilizer suction channels on the amount of fertilizer absorption was studied，as well as the hydraulic law of the fertilizer pump． The results show that the main pipe inlet pressure and the number of fertilizer suction channels have effects on the amount of fertilizer absorption，while the main pipe inlet flow has no effect on the amount of fertilizer absorption． When all three fertilizer absorption channels are opened，the total amount of fertilizer absorption decreases with the increase of inlet pressure of main pipe． When one or two fertilizer absorption channels are opened，the total amount of fertilizer absorption remains basically unchanged within a certain pressure range，and then gradually decreases． The regression model of total fertilizer absorption，inlet pressure of main pipe and opening number of fertilizer absorption channels was established and could be used for fertilizer absorption calculation． The efficiency of pump increases with the increase of inlet pressure of main pipe and reaches the highest when all the three fertilizer absorption channels are opened． The law of absorbing fertilizer and the law of hydraulic power of fertilizer pump，which are explored in this paper，can provide reference for the selection and design of fertilizer pump．

In order to study the characteristics of soil water infiltration in desert steppe and compare the differences among different determination methods，the sierozem of Ningxia natural grassland was taken as the research object． The infiltration process was determined by double－ring method and cutting ring method． The test results and influencing factors of the two methods were analyzed and compared． The models were used to fit the soil infiltration process． The results indicated that the initial infiltration rate，steady infiltration rate，average infiltration rate and steady infiltration time measured by the cutting ring method were all smaller than that of the double－ring method，which are 77．69% ～ 94．67%，27．69% ～ 52．88%，56．74% ～ 64．79% and 12．50% ～ 42．5% respectively． Double－ring method was more suitable to describe the process of infiltration rate changing with time by Horton model，Kostiakov model was more suitable for cutting ring method． Quadratic equation was the best fitting method for the cumulative infiltration of soil，and its determination coefficient Ｒ2 was above 0．991． The influence of soil physical properties on infiltration characteristics was slightly different due to the difference of soil internal conditions in the two methods

The effects of different nitrogen levels on photosynthetic rate (Pn), stomatal conductance (Gs), intercellular carbon dioxide concentration (Ci), total nitrogen content and chlorophyll content of apple leaves under water storage pit irrigation were studied. The correlation between Pn and the latter four factors was analyzed to provide reference for exploring the reasonable nitrogen application range of apple under water storage pit irrigation. The mechanism of Nitrogen Application on photosynthetic rate was provided. The nitrogen levels (0,10,20,40kg N/mu) of four water storage pits were set up and compared with the ground application. Pn,Gs,Ci,the contents of total nitrogen and chlorophyll in leaves before and after fertilization were determined. The results showed that: (1) under the same nitrogen application rate, the effect of Nitrogen Application on Photosynthesis of apple leaves under water storage pit irrigation was more significant than that under the same nitrogen application rate; (2) with the increase of nitrogen application rate, the total nitrogen content and Gs of apple leaves increased first and then stabilized, chlorophyll content and Pn increased first and then decreased, but Ci had no significant change; (3) After nitrogen application, the correlation between Pn and Gs, total nitrogen content, chlorophyll content was strong, but the correlation between Pn and CI was weak. (4) T3 treatment (20 kgN/mu) was more beneficial to photosynthesis of apple leaves under water storage pit irrigation.

In order to study the effect of Micro－sprinkler Irrigation on grape physiology and yield in extreme arid area，the SPAD value， chlorophyll content and yield of grape leaves at different growth stages were measured，and the variation characteristics and correlation of SPAD value and chlorophyll content of grape leaves under different micro－sprinkler periods were analyzed． The results showed that the SPAD values of all treatments decreased at first and then increased at different spraying cycles． The daily variation ranged from 38．31 to 43．8． The daily average SPAD values of spraying water for 1 hour per day were the highest，which was 42．0． Then the control treatment and spraying water for 2 hours every other day were 41．2 and 40．3，respectively． The lowest SPAD value was 39．3 after 2 days of spraying for 3 hours． The correlation between SPAD value and chlorophyll a，chlorophyll b and total chlorophyll content was significant． The regression equations were Ca = 0．102 8 VSPAD －2．226 6，Cb = 0．079 6 VSPAD －2．374 9 and Ct = 0．182 4 VSPAD －4．460 2，respectively． In terms of grape quality and yield， micro－spraying could increase VC content，polyphenol content and tannin content，and increase grape yield by 5．4% on average． The results showed that reasonable micro－spraying period could improve the chlorophyll content of grape leaves and increase grape yield，but chlorophyll was only one index of the grape physiological growth indexes． So the effects of photosynthesis，chlorophyll fluorescence and other indicators on grape physiology need to be further studied in order to further reveal the mechanism of grape yield increase under micro－spraying irrigation conditions．

The effects of different nitrogen levels in water storage pits on root length density and root surface area density of apple trees are studied，which can provide a basis for determining the reasonable nitrogen application range of apple trees under the condition of water storage pit irrigation． In this paper，7 years growth short anvil and dense red Fuji apple tree are studied． Four nitrogen levels( 0、10、20、40 kg / hm2 ) of water storage pits are set，namely the treatment of T1，T2，T3，T4，and the ground fertilization treatment is set as a control group CK． The root length density and root surface area density of apple trees with different soil depths before and after fertilization are measured by micro－root tube． The results show that: nitrogen application can promote the growth of apple tree roots effectively; the growth rate of root length density and root surface area density increases first and then decreases with the increase of nitrogen application rate; comparing CK to T2 under the same level of nitrogen application，the roots of CK are better than that of T2 in the topsoil，but the T2 apple tree roots develop better in the middle and deep soil． Comprehensively considering the growth and development of apple tree roots，T3 is the most suitable for the growth of apple tree roots．

The physical model test method was used to test the water－sand separation efficiency of gill－piece separation device ( GPSD) and common pipe under the same sediment concentration and different flow rates． The experimental results show that the vertical and horizontal heterogravity flow also occurs in GPSD under the condition of moving water． When the sediment content is 10 kg /m3 ，the separation efficiency of GPSD is 1．03～ 2．26，1．16～ 2．45，1．30～ 2．70，1．58～ 3．85，1．65～ 1．60 times of that of the common pipe under the conditions of 0．3，0．5，0．7，0．9 and 1．1 m3 /h of the inlet flow of muddy water． The optimal muddy water inlet flow rate of GPSD is 0．9 m3 /h，the water －sand separation efficiency can reach 34．12%，and the water consumption rate is 5．78%．When the inlet flow of muddy water is 0．3～ 0．9 m/ h，the separation efficiency of water and sediment with time can be divided into three stages of slow increase，fast increase and slow increase， while when the inlet flow of muddy water is 1．10 m3 /h，there is only a slow increase stage

The effects of different irrigation amount on the growth index，quality and dry matter accumulation of pepper were analyzed and the water consumption characteristics were studied during the whole growth period via the field experiment of pigmented pepper in Yumen City of Shule Ｒiver Basin． The most suitable irrigation schedule for the Shule Ｒiver Basin was proposed by comprehensively considering the indicators of yield，water use efficiency，etc． The results showed that the plant height and the leaf area coefficient in the fruit setting period were 3．2 times and 5．6 times of those of the flowering stage，respectively． During the flowering stage to the fruit setting stage，so as to the highest stage of pepper plant height and leaf area growth; The nutrients stored in the pepper organs gradually moved to the fruits and seeds from the fruit setting period to the expansion stage，the ratio of the dry weight of the fruits and the whole plants gradually increased． The average dry matter was increased by 22．88 g，accounting for more than 50% of the total dry matter during the whole growth period． The effect of the amount on the nutritional quality of pepper was significant． Among them，DG2 significantly improved the quality of pepper compared with other treatments，which was significantly higher than that of control CK by 3． 61%，3． 90%，13． 88% and 29． 76%，respectively． The water consumption during the whole growth period decreased from low to high． The trend of change is that the water consumption modulus is the largest during the flowering period，and the water consumption intensity during the fruit setting period is the largest． The water consumption during the three growth stages of flowering，fruit setting and expansion period accounts for more than 60% of the water consumption during the whole growth period，which were the most sensitive periods for moisture to the pepper，the water and nutrient requirements for the normal growth of the pepper should be ensured． The most suitable irrigation scheduling of pepper membrane under drip irrigation was proposed that the whole growth period was 9 times and the irrigation quota was 3 540 m3 /hm2 through comprehensive consideration of the yield of pepper and the efficiency of water production．

Under field conditions，the experiment，with 10 years growth of dwarfing ChangfuⅡtype Ｒed Fuji apple trees treated as materials， the effect of different irrigation upper and lower limits，including water storage pit irrigation treatment T1，80% and 60% of field water capacity，T2，90% and 70% of field water capacity，T3，100% and 80% of field water capacity，and control treatment of ground irrigation， CK，80% and 60% of field water capacity，on the diurnal variation of transpiration and its influencing factors of apple tree leaves were studied，and the response of leaf water use efficiency to different upper and lower irrigation levels was analyzed． The results show that: the diurnal variation of transpiration rate of apple leaves under different treatments is basically consistent，both of which are unimodal curves and the peak values appear at 13 ∶ 00． The average daily transpiration rate is ranked as T3＞T2＞CK＞T1． Leaf transpiration rate is mainly affected by soil moisture content，stomatal conductance，intercellular CO2 concentration，atmospheric temperature and leaf surface temperature． The diurnal variation of water use efficiency of leaves shows a trend of first decreasing and then increasing． The average daily water use efficiency of leaves is ranked as T1＞T2＞T3＞CK，and there are significant differences between T1，T2，T3 and CK． According to the comprehensive comparison，T1 has the most significant water－saving effect．

In order to explore the effect of biochar application on soil enzyme activities in water－saving irrigation paddy fields，the changes of soil enzyme activities with soil depth and rice growth under different water － carbon regulation scenarios were analyzed based on field experiments in Taihu Lake region in China． The results showed that under water－saving irrigation，the application of biochar had a certain effect on improving soil enzyme activity． With the increase of biochar application amount，the effect of biochar on soil hydrogen peroxidase activity was weaker than that of saccharase． Compared with the control treatment，the soil hydrogen peroxidase activities was increased by 1．89% ～ 4．64% and 6．67% ～ 8．75%，respectively，when treated with biochar application at 20 t /hm2 and 40 t /hm2 ，and saccharase activity was increased by 3． 21% ～ 23． 38% and 35． 26% ～ 73． 43% respectively． Water －saving irrigation increased the activities of soil hydrogen peroxidase and saccharase，and the degree of improvement gradually increased with the growth of rice，compared with flooding irrigation． Under water－saving irrigation，the activities of soil hydrogen peroxidase and saccharase in paddy fields were increased by 4．26% ～ 12．44% and 4．88% ～ 20．98%，respectively，compared with conventional irrigation． The soil saccharase activities of different biochar application rates were significantly different at the tillering stage，and decreased gradually during the middle and late stages of rice growth． The soil hydrogen peroxidase activities at the growth stage of rice increased first and then decreased with the increase of soil depth，and the soil saccharase activity decreased gradually with the deepening of soil layer． Therefore，the coupling of water－saving irrigation and biochar application is a recommended water－carbon management mode for paddy fields，which significantly increased the soil enzyme activities in paddies．

In order to study the influence of water with different salinity on the infiltration law of loam interlayer in sandy loam，four salinity treatments were set，namely 0，1，3 and 5 g /L，to carry out the indoor soil column vertical one－dimensional water infiltration test． The results show that the interlayer of loam has impervious effect on water infiltration with different salinity; the cumulative infiltration amount of each treatment presents a nonlinear change with time before the wetting front reaches the interlayer boundary，and a linear change with time after passing through the interlayer; the relationship between the stable infiltration rates of each treatment is V( 3 g /L) ＞V( 5 g /L) ＞V( 1 g /L) ＞V( 0 g /L) ; the salinity ranges from 0 to 3 g /L，and the accumulated infiltration amount and soil moisture content increase with the increase of salinity; at the end of infiltration，the upper layer of interlayer interface is desalted，and the lower layer of interlayer interface is salt－accumulated．

Ｒeducing the total phosphorus ( TP) concentration has become an important part of river pollution control in China． In order to reveal the mechanism of the influence of river sinuosity on phosphorus ( P) removal in water，four groups of circulating water tests with different river sinuosity were conducted to compare and study the migration and transformation characteristics of phosphorus in overlying water and pore water along river banks over time． The results show that: The decrease process of total phosphorus concentration in overlying water can be divided into two stages: fast and slow． In the fast descending stage，the decreasing rate of total phosphorus concentration in the overlying water of the high － sinuosity river is significantly higher than that of the low － sinuosity river． The removal efficiency of total phosphorus in overlying water increases with the increase of sinuosity． Due to the influence of longitudinal hyporheic exchange and lateral diffusion，the total phosphorus concentration in pore water at each point on the banks of curved rivers is different ( 1# ＞ 2#; 3 # ＞ 4 #; 5# ＞ 6#) ; under the influence of lateral diffusion，the total phosphorus concentration in the pore water decreases along the direction away from the channel． The removal efficiency of phosphorus in overlying water is significantly affected by the longitudinal hyporheic exchange but not by the transverse diffusion．

The southern Laizhou Bay area is located at the overlapping zone of the Shandong Peninsula Blue Economic Zone and the Yellow Ｒiver Delta Highly Efficient Ecological Economic Zone and has significant location advantages． The occurrence and aggravation of groundwater salinization posed threats to the industrial and agricultural production and drinking water safety for residents． Therefore，it is important to fully understand the status quo of groundwater salinity and master its main influencing factors． Through field investigation and water sample collection test，six indicators including total dissolved solid ( TDS) ，Cl － ，sodium adsorption ratio ( SAＲ) ，potential salinity，NO+ 3 and SO2－ 4 are selected for comprehensive evaluation by using analytic hierarchy process ( AHP) ，and the main causes of salinity are identified through comparative analysis． The results show that the degree of groundwater salinity is strong in the north and weak in the south，and the salinity area is large in the middle and east and small in the west． At present，the degree of salinity of groundwater is relatively heavy，and the salinity area is up to 3 132．13 km2 ，accounting for 70．17% of the study area． The main cause of groundwater salinity in this area is the intrusion of sea ( salty) water． 

In view of the problems that the single component score( Fi ) in traditional Nemerow index method is not successive and each single component maximum score ( Fmax ) is excessively outstanding，in this paper，entropy weight method and binomial coefficient method are combined to improve the Nemerow index method and the water quality evaluation is conducted based on the water quality test results of Pengzhou West Sichuan gas field． The evaluation results show that the improved Nemerow index method solves the problem of Fi discontinuity and overemphasis on Fmax in the traditional method，and the evaluation results are in line with the reality and the distribution in the five water quality grades is more continuous and even.

The research objective of this paper is forecasting the water consumption trend for decision support． The synthesis method from qualitative to quantitative is adopted． The change rate of each index is taken as the processing unit，and the statistical index is screened by PCCs－DEMATEL method． The BP neural network is used to construct annual water consumption prediction model，and compared with the weighted exponential smoothing method． The application of the model in Guangzhou shows that the BP neural network water consumption prediction model based on PCCs－DEMATEL index screening can better predict the regional annual water consumption，and provide reliable data supporting for water resources decision－making and analysis．

For water saving irrigation mode of operation and management, the optimal selection of multiple attribute characteristic of each scheme index with entropy value method and attribute recognition theory, established a comprehensive evaluation model of entropy attribute recognition model of operation and management, by calculating the index attribute measure, gray nearness and scoring criteria for sorting analysis, to select the optimal model. Entropy weight can reduce the error caused by subjective factors. Attribute recognition effective discriminant indicator value attribute measure. The calculation of grey proximity judges the level of management mode from an objective perspective. This model is clear in thinking and easy to calculate, and can provide technical reference for managers to improve the existing management mode and improve the existing management mode.

Aiming at the randomness and fuzziness of the qualitative concept of each evaluation index in the risk evaluation process of contract water－saving management，a comprehensive evaluation method based on cloud model is proposed． The analytic hierarchy process ( AHP) is used to determine the index weight，and the conceptual cloud model is obtained by cloud transformation of the risk evaluation standard of the contract water－saving management project through the forward cloud generator． The cloud droplets are obtained by the expert scoring method，and the floating operation method and the comprehensive operation method are used to realize the conversion of the contract water－saving management project from the low level index to the high level index． The results are converted into cloud maps and compared with the conceptual cloud model of risk assessment criteria to obtain the evaluation results． Finally，through case analysis，the effectiveness and feasibility of applying cloud model to risk assessment of contract water－saving management are proved．

Planting area in Huang－huai Plain was taken as research object，a mathematical model for selecting appropriate water－saving techniques was established using hierarchical analysis and fuzzy mathematics in terms of natural geography，agricultural development， ecological environment，and eco－system status． In view of single－ and multiple－factor methods，suitable water－saving irrigation technique was finally put forwards and the most favourite water－saving irrigation technique was also recommended for planting area of Huang－huai Plain

Based on the field survey data of 251 peasant households in Shaanxi province and the binary logit model，this paper empirically analyzes the impact of part－time employment and farmers＇ agricultural water resource shortage perception on farmers＇ adoption of water－saving technology． The main research conclusions are as follows: farmers ＇ agricultural water resource shortage perception has a positive and significant impact on water－saving technology adoption behavior，and farmers＇ part－time employment degree has a negative and significant impact on water－saving technology adoption behavior． The part－time employment degree of farmers can significantly negatively adjust the relationship between farmers＇ agricultural water resource shortage perception and their adoption of water － saving technologies． Among the control variables，age，arable land area，mutual trust，policy understanding and other variables all significantly affect the adoption of water－ saving technologies by farmers．