Most of the cultivated land in Guangxi is located at hillslope with complex terrain. The heterogeneity of soil and the undulation of terrain result in the strong spatial and temporal variability of soil moisture, which leads to a severe difficulty for soil moisture monitoring and management. Based on the soil moisture data collected via TRIM in 2017 from 60 experimental plots in Chongzuo, Guangxi, this paper analyzes the spatial and temporal variability of the soil moisture, and its correlation with related factors. Moreover, the temporal stability feature of the soil moisture is obtained. The results show that the annual mean soil moisture spatially varies from 0.10 to 0.60, which is closely related to the field terrain and soil texture. The temporal change of spatially-averaged soil water content, which ranges from 0.21 to 0.30, has a good relationship with rainfall and evaporation and other meteorological conditions, and there is a great probability of soil water stress from September to November. The temporal stability analysis indicates that the No.3-2 experimental plot is the most representative location for representing the spatially-mean soil water for the site. It can be concluded that the soil moisture at this hillslope site has significant spatial and temporal variability, and the tools of statistics, correlation analysis, and temporal stability analysis can be employed to assess the soil moisture variability and optimize the soil water observation strategy.

In order to study the physiological response characteristics and yield changes of different winter wheat varieties under different water treatment conditions, and to evaluate their regional planting suitability, the physiological characteristics of two main drought-resistant wheat varieties (Yannong 19 and Aikang 58) in Huaibei, Anhui Province were analyzed under drought stress and normal water conditions. The results showed that light drought in the single growth period and light drought in the whole growth period had no significant effect on the growth and yield of winter wheat. Both severe drought in the single growth period and middle drought in the whole growth period significantly inhibited normal wheat growth and caused permanent stress. Under the condition of no or light drought, both physiological indexes and yield of Aikang 58 were better than those of AiKang58. However, when drought degree increased, AiKang58 had stronger adaptability to the environment, and the yield reduction was significantly lower than that of Yannong 19. So planting Yannong 19 in the southern part of the Huaibei Plain, and planting Aikang 58 in the northern plain were more conducive to the efficient use of regional water resources and food production security.

In order to clarify the influence of different types of ditches on nitrogen and phosphorus interception of non-point source pollution in cold and dry areas, this paper used a combination of indoor static and dynamic simulation and variance analysis to analyze the interception effect of different types of ditches on nitrogen and phosphorus from non-point source pollution in cold and dry areas. And in the dynamic experiment of the ecological ditch, the three factors of influent nitrogen and phosphorus concentration, influent flow and influent salinity were considered to explore their effects on the interception of non-point source pollution nitrogen and phosphorus in the ecological ditch. The results showed that: ① under the condition of static state and different hydraulic residence time (HRT), the interception effect of TN and TP in the ecological ditch was the best, and the average removal rates of TN and TP in low, middle and high influent nitrogen and phosphorus concentration were 78.93%, 69.82%, 58.61% and 90.31%, 84.47%, 76.71%, respectively; ② under the condition of dynamic and 48 hHRT, the average daily interception of TN and TP from high influent nitrogen and phosphorus concentration by ecological ditch were higher than that of low and medium influent nitrogen and phosphorus concentration by 75.91%, 55.58% and 67.08%, 44.02%, respectively; ③ under the condition of dynamic and medium influent nitrogen and phosphorus concentration, the average removal rates of TN and TP in low, middle and high influent flow are 43.09%, 36.29%, 29.72% and 79.77%, 76.58%, 70.68% respectively; ④ under the condition of dynamic, 48 h HRT and medium influent nitrogen and phosphorus concentration, the average removal rate of TN and TP in the low, middle and high influent salinity increased first and then decreased in the ecological ditch; ⑤ there were significant differences in TN and TP intercepted by different types of ditches, influent nitrogen and phosphorus concentration and influent flow (P0.05). It can be seen that ecological ditch has a good interception effect on nitrogen and phosphorus pollution from non-point sources in cold and dry regions. The research results can provide reference for the prevention, control and treatment of non-point source pollution.

In order to explore the changes of stomatal conductance and its response to meteorological factors of mature jujube in Aksu area under different water treatment conditions, so as to provide data support and theoretical basis for precise irrigation decision-making of jujube, in this study, the 6-year-old jujube trees in Akesu area were used as the research objects, the stomatal conductance curves of the trees under different water treatment conditions in the daily scale and irrigation cycle were measured by field experiments. The results showed that the stomatal conductance of jujube was the most sensitive to the wind direction in a single day scale in the irrigation water volume range of 300 to 450 m3/hm2; in an irrigation cycle, the most important meteorological factor affecting the stomatal conductance of jujube leaves was solar radiation. It can be concluded that the response degree and direction of stomatal conductance to meteorological factors are different in different time scales; under the condition of daily scale, the response of stomatal conductance to meteorological factors is not controlled by soil moisture content; on the scale of irrigation cycle, different soil moisture content determines the impact of meteorological factors on jujube trees.

In this study, field experiments were conducted to study the effects of different residual film quantities on tomato growth, so as to provide a basis for rational use of plastic film and promotion of residual film pollution prevention and control technology. Four different residual film levels (0, 200, 400 and 600 kg/hm2) were set for CK, T1, T2 and T3 treatments to determine the soil moisture, plant height and stem diameter, biomass and yield of tomatoes during the whole growth period. The results showed that the residual film hindered the migration of water, the soil moisture content of 0~20 cm first increased and then decreased with the increase of residual film, and the soil moisture content of 20~50 cm gradually decreased. The plant height and stem diameter of tomato at seedling stage were T1>CK>T2 >T3, the plant height and stem diameter of CK, T1 and T2 at the flowering and fruit-setting stage were all greater than that of T3. Stem and leaf dry weight and root dry weight of 20~50 cm first rose and then fell, with the maximum value of T1. Root weight in soil 0~20 cm was gradually increased due to the stimulation of residual film, and the influence of residual film on the biomass of tomato at early growth stage was greater than that at late growth stage. The yield of CK was significantly higher than that of T2 and T3 treatments by 4.80% and 13.63%. It can be seen that too much residual film will obviously affect the growth and yield of tomato, which is not conducive to the healthy development of agriculture.

The retention capacity of sand particles in micro irrigation has a direct impact on the filtration performance of the sand filter, and thus has an important impact on the filtration effect of the filter. So it is very important to analyze the ability of the surface of quartz sand particles to hold the impurities in the filtered water. In this paper, three kinds of quartz sand filter layer with the diameter range 1.00~1.18, 1.18~1.40 and 1.40~1.70 mm, respectively, were selected as samples. And the corrugation width corresponding to the maximum height of the surface profile and the maximum height of the profile was measured by the three-dimensional surface topography instrument. On this basis, the mechanism of the sand particles holding the impurities in the filtered water was analyzed and calculated. The results show that properly increasing the particle size of sand filter material can improve the stability of filtration performance of sand filter.

In order to improve the effect of soil moisture prediction in farmland, the neural network grey model was adopted. Firstly, the grey model was used to model the soil moisture data and the neural network was used to correct the errors. Then the neural network grey model considered the correlation degree between humidity data and only the single prediction model with a large correlation degree was combined for prediction. Finally, the algorithm process was given. The experimental results showed that the relative error and fluctuation of the predicted humidity value increased with the increase of soil depth. The comparison experiment of multiple models showed that the predicted value of soil moisture in the vertical depth of 70 cm and 80 cm by the model in this paper was close to the real value, the minimum and average value of residual prediction deviation index were 2.69 and 2.75, respectively, and the judgment coefficient of the model was 0.98. The results were superior to other prediction model indexes.

The scarcity of precipitation, the large amount of evaporation and the decreasing water resources of the Yellow River in Hetao Irrigation District have led to the increasingly prominent contradiction between water supply and demand in the irrigation district. The amount of groundwater resources in the irrigation district has played an important role in regional production and economic development. In order to explore the variation of groundwater burial depth in Hetao Irrigation District, the monthly groundwater depth data of 224 observation wells in each irrigation area in Hetao Irrigation District were collected and processed from 2008 to 2018, and the inter-annual and intra-annual groundwater in each irrigation area was analyzed by using the five point three times smoothing method buried depth variation. ArcGIS 10.2 software was used to draw the spatial variability of groundwater burial depth in each irrigation area. The main driving factors that influence the change of groundwater depth were studied by combining the grey relational degree. The results show that the groundwater burial depth in Hetao Irrigation District is generally shallow, but under the influence of human activities and natural conditions, the groundwater extraction volume in the irrigation area increases year by year, the burial depth decreases year by year, and the amount of evaporation and water diversion from the Yellow River has a greater impact on groundwater depth. Relevant departments should reasonably develop groundwater resources, effectively improve the utilization rate of water resources in the irrigation area, and protect the water ecological environment in the irrigation area.

With the development of protected field agriculture in China, greenhouse planting has become an important part to provide vegetables and fruits. At present, the research on water demand and irrigation system of protected agricultural field crops still needs to be improved. This paper summarized the main influencing factors and calculation methods of the water demand of protected agricultural field crops by sorting out the previous studies on the water demand of protected agricultural field crops, and proposed to strengthen the microclimate research of greenhouse, so as to further understand the influence process of various environmental factors of greenhouse on crops and improve the research on various factors affecting the water demand of crops.

Aiming at the prominent problems such as large difference in performance parameters and varying degree of automation of the current proportional fertilizer applicator, a kind of multi-channel proportional fertilizer applicator with dual pump system of “fertilizer suction pump + fertilizer injection pump” was designed. The design of probe micro-tube sampler was adopted in the detection system, and the pressure, flow, EC/pH control accuracy and concentration control response time of the fertilizer applicator system were tested. The results showed that the control precision of EC was less than 8%, the control precision of pH was ±0.1, and the adjust response time of EC/pH was less than 120 s. The multi-channel proportion fertilizer has the advantages of accurate regulation of water and fertilizer, rapid response, uniform fertilizer injection and stable operation, so can meet the field, greenhouse and other irrigation scale users of water and fertilizer integration needs.

The cross-sectional area of the traditional emitter is generally below 1 mm2, which is very likely to cause the flow channel structure to be clogged. Taking the rod emitter as the basic research object, the large cross-sectional area of the labyrinth channel is adopted, and the spiral branching channel is creatively set. The orthogonal characteristic method is used to simulate and analyze the influence of spiral branching channel key feature structure size on emitter hydraulic characteristics. The results show that the addition of the spiral branching channel has enhanced the water flow turbulent effect inside the emitter, and realizes the transition of the flow pattern from the laminar flow to the turbulent flow in the labyrinth channel with large cross-sectional area. The relationship between the hydraulic characteristics of emitter and the key structural parameters of spiral branching channel are proposed. It indicates that the arc radius R of the spiral branching channel has the greatest influence on the flow coefficient k and the flow index x, which provides a reference for the optimization of the hydraulic characteristics of the emitter.

It is very important to accurately grasp the dynamic change of soil moisture for making irrigation plan. Seven factors of hydrometeorology including soil water, groundwater depth, rainfall, water surface evaporation, wind speed, sunshine hours, temperature and absolute humidity were used in Wudaogou experimental station from 1991 to 2018. Through correlation analysis, four key factors of hydrometeorology were selected. Taking the most influential as the initial variables and adding them to four factors one by one, the multiple regression prediction models of soil moisture content in different growth stages and different soil layers (0~0.2, 0.2~0.4, 0.4~0.6, 0.6~0.8, 0.8~1.0, 0~0.5 m) of summer maize were established. The results showed that the correlation between soil moisture and meteorological factors in different soil layers was consistent; the correlation between soil moisture with groundwater depth and absolute humidity was the largest; the correlation between soil moisture with air temperature and absolute humidity was the most significant in flowering maturity period; in other growth stages, the correlation between soil moisture with groundwater depth and absolute humidity was the largest; with the increase of key influencing factors, the prediction accuracy was improved; when the influencing factors were 4, R2 was 0.99 at most; the soil moisture models of different soil layers had better prediction ability; with the increase of depth, the average relative error could be controlled within 0.1.This study is of great significance to grasp the changes of soil water in each growth stage of crops and guide the precise irrigation of crops.

The influences of land use and cover change on evapotranspiration (ET) is an important topic, which is of great significance to the agricultural development in arid areas. With the climate change and the expansion of human activities, the land use types of the underlying surface of the Loess Plateau in the arid region of China have been changing dramatically. The regional evaporation capacity changes significantly. Based on Penman-Monteith-Leung retrieval model, this study collected 98 stations of different land use types in the dry area from 2010 to 2015 from satellite remote sensing data and ground data to quantitatively study the change characteristics of regional ET values. The change characteristics of ET value of land use types on different underlying surfaces were analyzed, and the influences of transformation from paddy field, dry land and grassland to city on evapotranspiration were mainly observed. The results show that the urbanization of dryland significantly increases the regional evapotranspiration, and the change range of ET is 0.0449mm/year. The urbanization of grassland weakens the regional evapotranspiration capacity, and the change rate of ET is -0.0248mm/year. During the process of paddy field urbanization, there is no obvious fluctuation in regional ET.

In order to explore the difference between soil temperature and water content change in gravel-mulched land and bare land, based on outdoor simulated rainfall test, at the same time, the temperature of gravel-mulched land and bare land under the condition of no natural rainfall was also observed, the variation rule of ground temperature and water content and the relationship between them were compared and analyzed. The results showed that the temperature of the soil layer of 0~50 cm in the control group was 0.5~4.5 ℃ higher than that of the bare land under the condition of no rainfall; the ground temperature at 10~50 cm on sandy land was 0.5~3.5 ℃ higher than that of bare land; Under simulated rainfall conditions of 10 mm, the soil moisture content of gravel-mulched land and bare land had a large change range at 0~15 cm, and the moisture content of 15~50 cm had a small change range. The evaporation rate of bare land was greater than that of gravel-mulched land; Pearson correlation analysis was performed on the soil temperature and moisture content of the gravel-mulched and bare land, and the results showed that there was a correlation between the moisture content and temperature of different soil layers. Regression analysis was used to establish a functional relationship between soil temperature and water content. Based on this function, the water state can be inferred from the soil temperature.

To solve the air humidity sensor deployment in greenhouse variable micro-spray operation, based on the classical continuous particle swarm idea and algorithm framework, the problem representation method and speed-position rule are redefined to optimize the air humidity sensor deployment;The fitness function is constructed by using space-time collaborative Kriging interpolation method. The position and number of sensors are obtained by iterative calculation of discrete particle swarm optimization algorithm for the fitness function of the design. Through the simulation experiment, the accuracy of the air humidity field reconstruction and the statistical method verification are carried out on the sampled values of the final sensor deployment using Kriging interpolation and unoptimized data three-dimensional map. The effectiveness of the algorithm is verified, which lays a foundation for the greenhouse variable micro-spray operation.

In order to find out the spatial and temporal distribution characteristics of surface water-soil water-groundwater in the Dalhan Maomingan Joint Banner, this paper applies the isotope tracing method, which is regarded as the “DNA” exploration of water body, to conduct sampling analysis of surface water, soil water and groundwater in four typical areas. According to the results of isotope detection, the spatial and temporal distribution characteristics of each water body are explored. It is revealed that the main recharge source of surface water, soil water and groundwater in the study area is atmospheric precipitation, which only complements in some time periods and regions. From the perspective of time and space changes, the surface water and groundwater in the study area change little with time, but the isotope content gradually increases with the spatial change from west to east. The soil water is not changed with the space. In the change with time, the soil water at a depth of 0~125 cm changes greatly with time under the influence of external environment, while the isotope content of deep soil water gradually tends to be stable.

In view of the problems of unstable control algorithm and poor adaptive ability of irrigation system in facility agriculture, an adaptive fuzzy controller was introduced to improve its performance, so as to obtain the optimal control method with high control accuracy and weak oscillation. The results showed that the variable universe fuzzy-PID control system had the advantages of lower overshoot, short adjusting time and high stability. Compared with the traditional fuzzy PID, the control effect was improved significantly. At the same time, the field test results showed that the system could be automatically controlled according to the soil moisture data, so that the soil moisture was always kept near the given value, which realized the accurate management and control of irrigation, and provided a new solution for the development of precision irrigation in facility agriculture.

In order to explore the flow measurement accuracy and influence factors of the automatic flow-measuring device based on dilution method in the rectangular open channel, the YD-1H type salinometer was used to measure the salinity changes of the water flow in the rectangular open channel before and after the tracer solution was put into it, and the salinity values of the water flow in each period could be obtained. The automatic flow measurement device based on dilution method combines the YD-1H type salinometer with the cloud platform of the Internet of things to automatically measure the water flow salinity, thus obtaining the flow rate. By observing the flow of electromagnetic flowmeter and the analysis of the experimental measurement data, it was found that the average relative error between the flow rate obtained by the automatic flow measuring device based on dilution method and the actual flow rate in the rectangular open channel was less than 4%, which met the measurement accuracy requirement of the open channel flow measuring device, and further proved the feasibility of the automatic flow measuring device based on dilution method and had certain popularization and application value.

In order to get rid of the wired power supply, the intelligent solenoid valve system based on the power supply of ultra-micro hydro-generator was studied and designed, and the “wireless power + network” was realized. The dual power supply system of ultra-micro hydro-generator and solar panel was used to charge the rechargeable lithium battery, and the physical and mathematical methods such as hydrodynamics and electricity were used to calculate the power generation efficiency. The rechargeable lithium battery with the rated capacity of 6 800 mA?h was selected to supply power for YCL11 type bistable pulse solenoid valve and LTE-Luat communication control module. A set of testing device was designed and installed. The result shows that the hourly charging efficiency of the ultra-micro Hydro-generator was 1.23%~2.45%, in other words, the lithium battery with a rated capacity of 6 800 mA?h can be charged once between 40.8~81.6 h, while the solar charging plate can be charged about 5.44 h under normal working conditions, with a charging efficiency of 18.38% per hour. In the absence of ultra-micro hydro-generator and solar charging plate, a fully charged lithium battery with a rated capacity of 6 800 mA?h can be used for at least 89, 129 and 67 d under GPRS, WCDMA and LTE modes. If the charging efficiency of double generators reaches 1.12% (1/89), 0.77% (1/129) and 1.49% (1/67) per day, the power demand of the whole system can be met. The charging efficiency of the system was higher than the required charging efficiency, which can ensure the continuous operation of the system and meet the system design requirements. The successful development of the system will save a lot of power infrastructure construction for intelligent irrigation, and also contribute to the realization of intelligent irrigation in remote areas of China.

In order to solve the problem of water deterioration in paddy field after straw returning in the South of China, an experiment was conducted to simulate the flooding of the paddy field after straw returning. There were two treatments in the experiment, i.e., aeration with 0.5 hour and no aeration. The content of non-point source pollution such as the NH+4-N, NO-3-N, and total phosphorus (TP) in the surface water were analyzed. The results showed that the peak values of NH+4-N and TP concentrations in the field surface water could be reduced by 77.4% and 29.84% under the condition of aeration, respectively. NO-3-N and TP concentrations could be quickly increased and appeared to the peak values by aeration, and the aeration treatment could keep the dissolved oxygen content in a high level in the early and later flooding periods, which was beneficial to the water body being in an aerobic environment for a long time, and beneficial to reduce the risk of nitrogen and phosphorus non-point source pollution, and beneficial to the crop root growth. The results indicated that aeration treatment to flooded paddy fields after straw returning could increase the dissolved oxygen content in the paddy field effectively, shorten the duration of high concentration of nitrogen and phosphorus, and thus reduce the risk of water pollution.

Evaluating the quality of efficient water-saving irrigation services of new service subjects is of great significance for improving the management capacity and service level of farmland water conservancy. Based on the general principles of service quality evaluation (GB/T36733-2018) and the SERVQUAL model, a new service subject efficient water-saving irrigation service quality evaluation index system was constructed, and the evaluation index score was measured by means of comprehensive evaluation methods. The calculation results show that the comprehensive score of the service quality of the new service subject for efficient water-saving irrigation is 3.128 6, including 0.818 8 for service resources, 1.024 0 for service process and 1.285 8 for service results. It shows that the service quality of high-efficiency water-saving irrigation of new service subjects in Hutubi County, Xinjiang is in a good development stage. Therefore, a practical scheme to improve the service quality of efficient water-saving irrigation of the new service subject was proposed from the aspects of strengthening the talent construction of the service team, improving the response rate of fault treatment, and focusing on the economic demands of the service object, so as to provide reference for the evaluation of the service quality of water-saving irrigation in Xinjiang.