In the agricultural production of Xinjiang Corps， the popularization and use of drip irrigation system has been basically realized. However， the widely used fertilizer tank in drip irrigation system often has the problems of difficult to control the concentration of fertilizer solution and difficult control of time. The production effect of advanced foreign irrigation and fertilization equipment in the domestic application is not ideal and cannot adapt to domestic climate conditions and planting production environment. Therefore， an accurate integrated water and fertilizer automatic control system is urgently needed in China to solve this drawback. In view of this phenomenon， this paper designed a set of water and fertilizer EC value control system based on fuzzy-PI composite control. Combined with the characteristics of good robustness of fuzzy control and high precision of PI control， the EC value of water and fertilizer was adjusted by controlling the opening time of solenoid valve in mother liquid tank. The system under the fuzzy-PI compound control was simulated with Matlab software， and in turn， compared with the simulation results of the system under PI control and fuzzy control. The results show that compared with PI control and fuzzy control separately， the system designed in this paper under the fuzzy-PI composite control can significantly shorten the overshoot and adjustment time， and has better dynamic performance. It can be used to control the EC value of water and fertilizer in drip irrigation system of cotton field.

Aeolian sandy soil is widely distributed in Hetian area with poor water and fertilizer retention. In order to find out the relationship between irrigation quota and deep percolation in aeolian sandy soil and provide theoretical basis for scientific irrigation of facility agriculture in Hetian area， in this paper， the radish field in solar greenhouse in aeolian sandy soil in Hetian was taken as the research object， five irrigation levels were set to carry out irrigation experiment with fixed irrigation period and variable irrigation quota. At the same time， the deep percolation under the ground depth of 60 cm was monitored by the deep percolation meter， and the relationship between deep percolation and drip irrigation quota was analyzed. The results showed as follows: ①The critical value of irrigation quota for deep leakage in different growth stages of radish was 8.1 mm/ time at seedling stage， 10.4 mm/ time at leaf growth stage and fleshy root growth stage. ② The deep leakage of T1-T5 treatments varied from 26.0 mm to 254.7 mm in the whole growth period; ③ The relationship between deep seepage amount and irrigation quota of radish field in solar greenhouse under the condition of wind-sand soil could be fitted with the primary and quadratic functions with irrigation quota as variables， the correlation indexes were all above 0.9， and the quadratic function had the better fitting effect.

In order to solve the problems of lacking water of economic forest in southern Ningxia and no infiltration to the root system (20~ 40 cm) distribution under light rain(4~16 mm)， a rain collecting device was designed and the horizontal and vertical movement characteristics of soil moisture under different rainfall conditions was studied through the indoor soil box test with rainfall as the control factor. The results showed that with the increase of rainfall， the cumulative infiltration amount increased gradually， and the infiltration rate decreased gradually. Under different rainfall conditions， the increment of soil water content in the vertical range of 0 ~ 40 cm increased first and then decreased with the increase of soil depth， and the radial distance from the infiltration irrigation device gradually decreased. After 24 h irrigation， the high moisture content areas were mainly distributed in the vertical direction of 20 ~ 40 cm and the radial direction of 0 ~ 20 cm， and the wetted body was roughly semi-ellipsoid. The water content of soil was significantly increased within the main root distribution range (20~60 cm) of the economic forest， which was conducive to alleviating the water shortage in the growth period of the economic forest and promoting its growth. The results of this study can provide reliable data support for the application of the irrigation device in the field.

Fruit cracking is a major physiological disaster that causes the loss of jujube industry, and fruit cracking is mainly caused by rainfall. At present, the mechanism of fruit cracking from the perspective of water physiology is not clear.In this study, Junjube, one of the largest cultivars with cultivated area in China, was selected as the test material, and the soil water content in the field was controlled at 45%±5%, 60%±5% and 80%±5% respectively from the white mature stage to the full red stage by the method of drip irrigation. The results showed that fruit cracking occurred in all stages when soil moisture content was 80%, the content of protein and proline was the best when soil moisture content was 60% in semi-red stage, and the content of proline was the best when soil moisture content was 45% in full red stage. The highest content of vitamin C and total phenol was found in 80% soil moisture at white mature stage. The contents of soluble sugar and starch and the ratio of sugar to acid were higher in 60% soil water content of semi-red stage, and higher in 45% soil water content of full-red stage. It is more suitable to improve the quality of Jujube jujube by controlling the soil water content to 60%±5% during white mature stage and semi-red stage and reducing the soil water content to 45%±5% during full red stage according to the indexes and fruit cracking rate, so as to achieve the effect of saving water and reducing fruit cracking.

In order to explore the high-yield and high-efficiency model of potato in the arid area of Ningxia， the growth and development characteristics of potato under mulch drip irrigation were studied by setting the interaction of water， nitrogen， phosphorus， and potassium. The results showed that with the increase of irrigation amount， the potato stem thickness and dry matter accumulation in arid areas increased. T9 treatment (irrigation amount 1 500 m³/hm²， nitrogen application rate 240 kg/hm²， phosphorus application rate 150 kg/hm²， potassium application rate 30 kg/hm²) had the largest tem thickness and dry matter accumulation in each growth period. The cumulative maximum amounts were 22.60 mm and 15.63 g/plant， respectively. With the increase of irrigation and nitrogen application， potato yield gradually increased， but it gradually decreased with the increase of phosphorus and potassium application； with the increase of irrigation and nitrogen application， water use efficiency first increased and then decreased. While with the increase of phosphorus and potassium application amount， WUE first decreased and then increased. The maximum potato yield of T9 treatment was 30.21 t/hm²， which was significantly different from other treatments. T8 treatment had the highest water use efficiency of 11.06 kg/m³， which was not significantly different from T6 and T5 treatments (P>0.05). Therefore， T8 treatment (irrigation amount 1 500 m³/hm²， nitrogen application rate 180 kg/hm²， phosphorus application rate 90 kg/hm²， potassium application rate 150 kg/hm²) can be used as a high-yield and efficient water and fertilizer management combination for potato in arid areas.

Aiming at the problems of instability and poor adaptability of the control algorithm of the greenhouse micro-spraying system， in this study， a smooth switching control algorithm was designed by using fuzzy rules. The step modeling method was used to set up the mathematical model of micro spray volume and air humidity， which simplified the greenhouse air humidity model. Finally， WiFi and ZigBee transmission technology were combined to build the greenhouse remote control system. The simulation results of Matlab/Simulink showed that the fuzzy switching control strategy had smaller overshoot and higher stability than the traditional fuzzy PID control， and could achieve better control effect. At the same time， the actual operation results showed that the packet loss rate of greenhouse micro-spray control system was less than 15%， and the greenhouse air humidity could be controlled at about 89%. The operation was stable and met the requirements of greenhouse air humidity control， which realized the precise control of greenhouse air humidity， and provided a solution for the development of agricultural fine control.

In this paper， an experimental study on the flow characteristics of DN50 socket type bend pipe was carried out， and the Relizable k-ε turbulence model was used to simulate the flow characteristics. The results of numerical simulation were in good agreement with the experimental results. Then， the flow of 45°， 60° and 90° bend pipes of DN20， DN40， DN63 and DN75 were numerically simulated. Through visualization analysis， it was found that the flow field of the bend pipe had backflow phenomenon in the downstream of the bend section， and there was a pair of symmetrical and opposite vortices at the downstream 50 mm cross section. With the increase of bending angle， the range of reflux and the degree of negative pressure increased gradually. The local resistance coefficient decreased with the Reynolds number and then gradually became constant. The local resistance coefficient of the 45°， 60° and 90° bending tubes in the resistance square area was 0.213， 0.462 and 1.127， respectively. The momentum equation was used to calculate the impact force of the water flow on the bend and the relationship between the impact force and the flow velocity was obtained by fitting， which could be used to predict the water pressure in the bend section.

In order to find out the effect of different water management methods on the distribution and bioavailability of soil phosphorus (P)， this study compared the distribution of total P (TP)， available P (AP)， and P fractions in an orchard soil between drip irrigation and flood irrigation， and discussed the effects of three nitrogen (N) application amounts (102， 204， and 306 kg/hm²) on the contents of different fractions of P (H₂O-P， NaHCO₃-P， NaOH-P， HCl-P， and residual P) in southern Xinjiang. The results showed that the soil TP content under drip irrigation gradually decreased with soil depths. However， the P content under flood irrigation was the highest at the soil depth of 40 cm. The content of AP in the 0-20 cm soil layer under drip irrigation was significantly higher than that under flood irrigation. The percentage of bioactive P (H₂O-P and NaHCO₃-P) measured by continuous extraction method in total P gradually decreased with soil depths， and drip irrigation was beneficial to the accumulation of bioactive P in the topsoil. NaHCO₃-P was the domain form of bioactive P in the soil under two irrigation methods. However， the average NaHCO₃-P_o content in flood irrigation soil was 2.4 and 4.2 times of that in drip irrigation soil， while the average NaHCO₃-P_i content under drip irrigation was about twice of that under flood irrigation. The bioavailable P fraction increased with N application amounts. The input of N fertilizer increased the content of highly bioactive P， but decreased the contents of HCl-P and residual P in the soil. Therefore， drip irrigation and N application are the effective ways to improve P availability and reduce the risk of P loss.

In order to explore the effects of different irrigation modes on yield traits and water use efficiency of summer maize in Huang-Huai-Hai plain， the treatments， including mulched shallow buried drip irrigation (T4)， shallow buried drip irrigation (T3)， mulched drip irrigation (T2)， drip irrigation (T1) and traditional border irrigation(CK) ， were set for two consecutive years from 2018-2019 to conduct field contrast tests. The indexes， including plant height， LAI， dry matter accumulation， yield and WUE， were measured. The results indicated that plant height， LAI， dry matter accumulation， grain yield， grain number per ear and WUE under all kinds of drip irrigation were significantly higher than those under CK， but there were no significant differences in effective spike and 1000 -grain weight among different irrigation treatments. The overall performance of maize traits and WUE under different drip irrigation treatments decreased in the order： T4>T3>T2>T1. However， the difference between T4 and T3 were not significant， indicating that there was no significant improvement in yield traits and WUE under shallow buried drip irrigation. Both mulched shallow buried drip irrigation and shallow buried drip irrigation could significant increases maize yield and WUE. In 2018， T4 (T3) increased the yield by 17.2% (15.9%)， 9.5% (8.2%) and 6.0% (4.9%) higher than those of CK， T1and T2， respectively； the WUE was increased by 33.3% (31.3%)， 12.1% (10.3%) and 7.0% (5.3%) ， respectively. In 2019， T4 (T3) increased the yield by 10.2% (7.9%)， 7.0% (4.8%) and 5.2% (3.0%)， respectively； the WUE was increased by 30.5% (25.2%)， 17.5% (12.7%)， 14.8% (10.1%)， respectively. Both mulched shallow buried drip irrigation and shallow buried drip irrigation had significant advantage in saving water and promoting yield， and there were no significant difference in yield and WUE between them. Due to surface without plastic mulching， shallow buried drip irrigation can not only save cost bust also effectively avoid residue film pollution. Therefore， it is the best irrigation method to save cost and increase yield for summer maize in Huang-Huai-Hai plain area.

In order to explore the physiological response mechanism of green pepper in different growth stages to water stress， in this study， the green pepper(Capsicum annuum var. Zhongjiao 107) was selected as test material， the effects of water deficit on stomatal characteristics， growth process and biomass of green pepper were studied by using different levels of water deficit treatment (full irrigation， FI； mild regulated deficit at seedling stage， SSMD； severe regulated deficit at seedling stage， SSSD； mild regulated deficit at flowering stage， FSMD； severe regulated deficit at flowering stage， FSSD). The results showed as follows ：① The stomatal density and stomatal width of green pepper were increased by regulating deficit at seedling stage；②The growth trend of stem diameter and plant height under full irrigation was significantly higher than that under water deficit treatment， and leaf area index (LAI) under regulated deficit treatment at flowering stage was the highest.③ The aboveground and underground biomass of severely regulated deficit green pepper at the seedling stage was the highest， and the water content of the regulated deficit plant tissue was the highest at the seedling stage. It can be concluded that severe water deficit at seedling stage is the most beneficial treatment to the growth and biomass accumulation of green pepper.

In order to propose a high-precision ET ₀ forecasting method suitable for the Sanjiang Plain， this study collected the daily weather forecast data and the daily measured meteorological data，using the FAO56-Penman-Monteith(FAO56-PM) calculations as a benchmark to compare the three ET ₀ forecasting models Hargreaves-Samani (HS)， Thornthwaite (TH)， and Blaney-Criddle (BC)， then sensitivity analysis are performed on the optimal model. The results show that： the mean absolute error of the above three models in the 1~7 d forecasting period are 0.66，0.65，0.65 mm/d， the root mean square error are 0.93， 0.96， 0.95 mm/d， the correlation coefficient are 0.857， 0.828， 0.840. For each foresight period， the best forecasting model is the HS model for the 1~5 d foresight period and the TH model for the 6~7 d foresight period. The overall forecasting accuracy from high to low is HS， TH and BC model. It is recommended to use HS model to carry out ET ₀ forecasting in the Sanjiang Plain， by which the error in the ET ₀ forecast is more sensitive to maximum temperature than minimum temperature. And the sensitivity of ET ₀ forecast value is the most affected by temperature forecast in summer and the least in winter. The overall error fluctuation of all four seasons is within the acceptable range. In a word， the HS model can provide a more accurate data base for irrigation forecasting， which is important for the development of water-saving irrigation.

The primary objective of this paper is to solve the problem of the low utilization rate of water and fertilizer resources in paddy field of the cold region. The rice in the cold region was selected as the research object， and different levels of water (W)， nitrogen (N)， potassium (K) and phosphorus (P) were applied and the second saturation test design was adopted. The regression equations between rice yield and W， N， K and P were established by quadratic regression analysis， and then the economic benefit of water and fertilizer resources input and output was analyzed based on the survey data of farmers. The results showed that all the factors promoted the rice yield， and the order of effect on rice yield was： W > N > K >P， the rice yield increased first and then decreased with the increase of each factor. The order of the interaction of the two factors on the yield was： N&K > N&W > K&W > N&P > P&W > K&P， the coupling of N&K， N&P， N&W， K&W， P&W all had synergistic effects， which promoted the increase of yield， however， the coupling of K and P had an alternative effect， which inhibited the increase of yield. The optimal input-output of water and fertilizer aiming at the maximum economic benefit was 128.87 kg/hm² of N， 85.56 kg/hm² of K， 41.74 kg/hm² of P and 5 510 m³/hm² of irrigation water， while the optimal yield was 15 524.22 kg/hm² and the maximum economic benefit was 43 607.54 yuan/hm². Therefore， reasonable water and fertilizer application ratio not only improves the efficiency of water and fertilizer utilization， but also greatly improves the yield and the economic benefits of rice planting.

In order to investigate the effects of water, fertilizer and interval of water dropper combination on growth, yield, quality and water fertilizer efficiency of spring/summer cucumber in solar greenhouse in arid areas of Ningxia, a three-factor three-level orthogonal test was conducted to analyze the plant height growth characteristics of each period by Logistic equation. By means of range analysis and variance analysis, the main order, significance and changing trend of the effects of water-fertilizer coupling and emitter spacing were studied. Meanwhile, the yield and quality indexes were comprehensively evaluated by using fuzzy mathematical membership function method to select the optimal combination. The results showed that the plant height of cucumber ‘S’-shaped growth process under different treatments can be divided into three stages: increasing period，linear growing period and slowly increasing period，which could be fitted by Logistic equation, and the correlation coefficient was as high as 0.97. The yield of spring/summer cucumber was stable in the first 3 months, accounting for 30.19%, 29.22% and 28.58% of the total output respectively. In the following 1 month, the yield dropped sharply, accounting for 12% of the total output. The effect of three factors on yield was shown as irrigation amount > fertilization concentration > interval of water dropper, irrigation amount had significant influence, while fertilization concentration and interval of water dropper had no significant influence. The highest yield treatment was TR1, up to 144 361 kg/hm², which was 44.92% higher than the lowest treatment TR9. The fuzzy membership function was used for comprehensive evaluation, the treatment TR2 performed best with an average membership function value of 0.70.The optimal horizontal combination of determining factors was determined as follows: irrigation volume of 3 040.95 m³/hm², fertilization concentration of 200 times liquid (740.55 kg/hm²), dropper spacing of 20 cm, and yield of 141 077.9 kg/hm².

In order to explore the influence of different fertilization strategies on the growth of tomatoes in greenhouses under micro-moisture irrigation， in this study， the tomatoes were planted in a planting box in the greenhouse， the fertilization concentration was respectively set to five different treatments，namely 200 mg/L (N1： the concentration during the whole growth period is 200 mg/L) and 200~400 mg/L (N2： 200 mg/L in the seedling stage， 400 mg/L in the fruiting and mature stages)， 400 mg/L (N3： 400 mg/L in the whole growth period)， 400~800 mg/L (N4： seedling Phase concentration is 400 mg/L， fruiting phase， maturity phase is 800 mg/L)， 800 mg/L (N5： whole growth period concentration is 800 mg/L)， and the indexes of moisture content， stem thickness， Plant height， leaf area， yield and water use efficiency during the whole growth period were measured. The results showed that there was no significant difference in soil water content among treatments with different fertilization concentrations， and the differences in various growth indexes of tomato under N4 and N5 treatments were not significant and better than those under other treatments， indicating that fertilization had little effect on soil water content. However， with the increase of fertilization concentration， the yield and residual growth indexes of tomato increased significantly. The tomato growth and yield of N4 treatment with less fertilizer concentration before and more fertilizer concentration later were not weaker than that of N5 treatment. Therefore， reducing fertilizer application at seedling stage， topdressing at flowering and fruit setting stage and maintaining high concentration of fertilizer application during the whole growth period were effective fertilization measures for the integrated cultivation of tomato with water and fertilizer under micro-watering irrigation.

Thermal conductivity is the basic parameter of soil heat transfer and plays an important role in many fields. The acquisition of soil thermal conductivity takes a lot of time and effort. In order to acquire the thermal conductivity of soil accurately， in this paper， the measured thermal conductivity values of 5 soil samples was compared with the predicted values of Campbell， Johansen， Cote-Konrad and Lu-Ren thermal models. A new parameter F related to soil texture was introduced to improve the Campbell model with large deviations. The NSE， RMSE， and PBISA of the improved Campbell model ranged from 0.938 to 0.996， 0.039 to 0.084 and -0.067 to 0.016，respectively， which were considerably better than those of the Campbell model (0.632 to 0.975， 0.089 to 0.217 and -0.011 to 0.252). Then， the thermal conductivity values of 10 soil samples from other regions were used to verify the improved model. The results showed that the predicted value of soil thermal conductivity was stably distributed around the 1∶1 line， and the modified model could also accurately calculate the soil thermal conductivity in other areas.

Water shortage is one of the major adverse factors that affect the sustainable development of Yunnan Province. Effectively developing agricultural water-saving is the base of achieve sustainable social and economic development in Yunnan Province. In order to ensuring the scientific development of agricultural water-saving in Yunnan Province， the Zoning of agricultural water-saving in Yunnan province was studied. In the study， counties and districts were taken as the division unit， 6 first-level indicators and 20 second-level indicators were chosen based on natural environmental conditions， social development conditions， economic capacity， and water resources conditions of 129 counties and cities in Yunnan. The principal component analysis (PCA) method was used to determine the zoning indicator system. The fuzzy clustering method was employed to divide the agricultural water-saving districts. The results indicated that the Yunnan Province could be divided into 4 first level agricultural water-saving districts (Water shortage area， Seasonal water shortage area， Engineering water shortage area， Dry-hot valley water shortage area) and 10 second level agricultural water-saving districts. According to local conditions， the agricultural water-saving development modes suitable for the regional characteristics were proposed. The application of this index system and method can obtain more reasonable results of agricultural water-saving zoning， which can provide scientific decision-making basis for agricultural water-saving management and sustainable development in Yunnan Province.

In order to explore the influence of single wing labyrinth drip irrigation belt slope， water inlet pressure and laying length on irrigation uniformity， this paper took three kinds of single-wing labyrinth drip irrigation belts as the research object and irrigation uniformity as the evaluation index， and the orthogonal test was designed to compare the variation law of irrigation uniformity of single-wing labyrinth drip irrigation belts with three different flow rate under the influence of water inlet pressure， laying length and slope. The comprehensive evaluation was carried out by visual analysis， variance analysis and multiple comparisons， and then the mathematical modeling of the test data was carried out by SPSS and PPR. The results showed that the order of the external factors of the irrigation uniformity of the three kind of single-wing labyrinth drip irrigation belts was pressure > slope > length； the model established by PPR had higher accuracy compared with SPSS. The research results not only provide a theoretical basis for the calculation and prediction of irrigation uniformity， but also provide an effective solution for the experimental optimization design of various disciplines and the modeling and analysis of high-dimensional data.