The reuse of irrigation water is an urgent problem for agricultural irrigation in arid and semi-arid regions of northwest China. Some research have showen that the composed envelope of geotextile and sand gravel has a remarkable filtering effect in the drainage process of farmland subsurface drainage pipe. In order to explore the anti-clogging situation of this kind of filter material, combined with the reuse of irrigation water resources in Ningxia, in this study, sand, zeolite and slag were used as filter materials, and a common geotextile was selected to construct composite envelope structures for subsurface drainage pipes. Based on four groups of indoor soil column permeability tests, an idea of improving gradient ratio method was proposed. Considering the weight of each internal structure, the anti-clogging situation of composite filter material was analyzed and studied. The test results show that the anti-clogging effect of composite envelope is better than that of only laying geotextile, while the anti-clogging effect of traditional sand gravel and absorbent material is slightly different. The composite envelope can use zeolite, slag and other adsorption materials to replace sand gravel, but it should meet the grading conditions of the filter material. When Cu > 4, it should not be short of small particle size filter material. The hydraulic gradient value of the filter material part accounts for a larger percentage of the overall hydraulic gradient value of the composite envelope. It is feasible to use the improved gradient ratio method considering the weight of each structure in the envelope to analyze and judge the siltation prevention situation.

Based on GLEAM satellite remote sensing data, the temporal and spatial evolution characteristics of surface evapotranspiration from 1980 to 2020 in 6 provinces and cities along the southeast coast of China were analyzed. The Mann-Kendall trend test and power spectrum wavelet analysis were used to analyze the trend and periodic characteristics of evapotranspiration from the annual and seasonal scales. The results show that the surface evapotranspiration in southeast coastal areas has shown a significant increasing trend in the past 40 years, with a growth rate of 1.87 mm/a. Summer contributed the most to annual evapotranspiration, accounting for 36.15%. Spring contributed the most to the growth of evapotranspiration, accounting for 36.73%. Evapotranspiration showed no obvious periodicity on the annual scale, but showed obvious periodicity on the seasonal scale. The results of this study can provide scientific reference for the study of hydrological cycle evolution in southeast coastal areas.

In order to ascertain the growth and development of cucumber in aeroponic cultivation, the effects of different factors (nutrient solution concentration and spray frequency) on the growth and development of cucumber were studied. The concentration of nutrient solution was expressed by EC (mS/cm), which was set as low concentration C1: 1.6 (seedling stage) and 2 (flowering and fruiting stage), medium concentration C2: 2 (seedling stage ) and 2.4 (flowering and fruiting stage), high concentration C3: 2.4 (seedling stage) and 2.8 (flowering and fruiting stage). The spray frequency was set as high frequency T1: 30 s/5 min (spray time / interval time), medium frequency T2: 30 s/15 min, low frequency T3: 30 s/30 min. During the experiment, the plant height, stem diameter, leaf area, leaf SPAD value (relative content of chlorophyll), melon length and melon diameter were monitored. The results showed that the plant height, stem diameter and leaf area of cucumber seedlings under C1T1 treatment were better than those under other treatments, and low concentration and high frequency irrigation was more conducive to the growth of cucumber seedlings. The plant height and stem diameter of cucumber plants grew fastest under C3T1 treatment at flowering and fruiting stage, and the SPAD value of leaves, melon length and melon diameter were better than those under other treatments. High concentration and high frequency were more conducive to the growth of cucumber at flowering and fruiting stage. At the end of the whole growth period, the principal component analysis method was used to comprehensively evaluate each treatment, and the comprehensive score of C3T1 treatment was the highest. Therefore, the treatment of C3T1 is the most conducive to the growth of cucumber plants.

Rice planting area in Sanjiang Plain accounts for 60% of the paddy field area of the province, and well irrigation rice accounts for 77%. The shortage of groundwater resources has become the bottleneck of agricultural development in Sanjiang Plain. In order to reduce agricultural irrigation water consumption, this study studied the growth characteristics and water consumption rules of rice under different irrigation modes to provide scientific basis and technical support for water-saving irrigation in Sanjiang Plain. Three irrigation modes, namely conventional irrigation (CG), controlled irrigation (KG) and shallow wet irrigation (QS), were set up in “rice 1703”in a field experiment. The yield structure of different irrigation modes was measured and the irrigation water productivity of paddy was calculated at the mature stage. The results showed that the CG model had the highest plant height and the KG model had the highest tillering number. The total water consumption in KG mode was 503 mm, which was 12.99% and 8.37% less than that in CG and QS mode, respectively. The variation trends of evapotranspiration and field seepage were obviously different with different irrigation modes. The rice mainly showed field seepage before tillering stage and evapotranspiration after tillering stage. Combined with rice yield and irrigation water productivity, the theoretical yield of KG model was 10 061 kg/hm², which was 10.98% and 5.28% higher than that of CG model and QS model, respectively. The irrigation water productivity of KG mode was 1.94 kg/m³, which was 24.36% and 20.50% higher than that of CG mode and QS mode, respectively. Based on the above research results, it can be seen that the water consumption of KG model management is the least and the final yield is the highest in the process of rice growth in Sanjiang Plain. Popularizing KG model in this region can reduce agricultural water consumption and solve the problems of over-exploitation of groundwater resources.

Accurate estimation of stomatal conductance is important for understanding the physiological mechanisms of water use in crops and predicting the actual evapotranspiration. This paper analyses the effects of different forms or combinations of environmental factors on the simulation accuracy of the Jarvis model based on the stomatal conductance observation data of summer maize in Beijing Daxing Experimental Base from 2016 to 2017, compares five stomatal conductance models (including the Jarvis multi-factor model, Jarvis two-factor model, Ball-Woodrow-Berry (BWB) model, Ball-Berry-Leuning (BBL) model and Unified Stomatal Optimization (USO) model), and proposes the applicability of the models at different scales. The results showed that both the form and combination of environmental response functions had a significant impact on the simulation accuracy of the Jarvis model. Among the five stomatal conductance models, the overall simulation accuracy was highest for the USO model, followed by the BBL model, BWB model, g_{sd -3} model, and g_{s -2} model. The Jarvis bivariate model requires less input data, is easy to obtain, and has better applicability at the regional scale. The BWB and BBL models have higher accuracy but require more difficult-to-obtain input data, making them suitable for estimating conductance at the field scale. The USO model requires less input data and is easily calibrated, with good applicability at both the field and regional scales. Therefore, in practical applications, it is necessary to comprehensively compare the combinations of environmental factors and the structures of the models to improve the accuracy of estimating evapotranspiration at the field or regional scale.

In order to effectively alleviate the agricultural water shortage in China, realize scientific water use in farmland, exert the advantages of water-saving irrigation technology, and improve the modernization level of corn planting, the drip irrigation technology under film was summarized. In this paper, the drip irrigation technology under mulch was evaluated according to the response law of corn yield, quality and soil properties. Comparing drip irrigation under film with traditional irrigation, shallow buried drip irrigation, drip irrigation without film mulching and other irrigation methods, this paper systematically discussed the characteristics, advantages, effects and shortcomings of drip irrigation under film, and summarized the appropriate irrigation methods under different conditions. On the basis of in-depth study on the fertilization system, irrigation system and water fertilizer coupling of drip irrigation under mulch, the synergetic effect of irrigation and fertilization was discussed through the impact on corn growth and water fertilizer utilization efficiency, aiming to refine the water and fertilizer threshold suitable for drip irrigation under mulch under different conditions, and achieve the purpose of water saving, fertilizer saving, high yield, high quality and high efficiency. Because drip irrigation under mulch can apply water soluble fertilizers, unconventional water sources and other irrigation water to the soil environment, the physical and chemical properties of the soil, soil enzymes and soil organisms will be affected. Analyzing the response of the soil ecosystem will be of great significance to improve soil fertility and reduce nutrient diversion loss. In order to optimize the material configuration and use methods of the drip irrigation technology under the film, this paper put forward solutions to the problems existing in the drip irrigation technology under the film, such as the film pollution, the reduction of groundwater recharge and the shortcomings of film mulching and drip irrigation. On this basis, in order to give better play to the advantages of drip irrigation under film, the technology of drip irrigation under film was prospected from the aspects of regional groundwater depth, combination of different irrigation methods, construction of crop growth model, crop quality and ecological problems, and application conditions of drip irrigation under film.

In order to explore the influence of mist on canopy environment regulation and growth of jujube fruit in hot air in summer, in this paper, Jun jujube was selected as the research object. Mist irrigation began at the flowering stage of jujube trees and ended before the fruit expansion stage. Three fog irrigation duration treatments were set, including three times a day, 20 min (T1), 40 min(T2), 60 min(T3) each time, and the control group CK only receiving indirect underground drip irrigation. The results showed that: ①The average air temperature during canopy misting in T1, T2 and T3 decreased significantly by 3.01%, 4.12% and 11.05% compared to CK, and the average relative air humidity increased significantly in T2 and T3 compared to CK, reaching 12.49% and 27.51%. ②Mist can effectively suppress soil evaporation between trees, with daily average soil evaporation reduced by 1.38%~17.78%, 1.11%~19.47% and 6.63%~48.11% in the T1, T2 and T3 treatments, respectively, compared to CK. ③Mist irrigation facilitated chlorophyll synthesis, with T1, T2 and T3 treatments increasing chlorophyll content (SPAD values) by 16.9%, 26.2% and 30.9%, respectively, compared to CK. ④Fruit expansion rates in the T1 and T2 treatments increased by 6.6% and 9% and 15.23 and 15.9% in longitudinal and transverse expansion rates, respectively, compared to CK. However, the longitudinal and transverse expansion rates of the T3 treatment decreased by 11.27% and 2.8%, respectively, compared to CK. The T2 treatment had the highest single fruit quality. T1 treatment had the highest yield, which increased by 6.5% and 47.57% compared with T2 and CK. Therefore, mist is beneficial for cooling and humidifying, reducing soil evaporation and increasing chlorophyll synthesis. T2 treatment was more favorable to Jun jujube fruit development, while the T1 treatment was more favorable to yield enhancement.

Throughfall is an important source of farmland soil moisture, and is very important for agricultural water management. However, the previous research results in different regions were quite different, and there was also a lack of in-depth research on the process of maize throughfall at each growth stage. The purpose of this study was to quantify the characteristics of throughfall in western Liaoning, and to deeply analyze the differences in the process of throughfall rate of maize in different growth periods. In this study, the natural rainfall experiment was carried out to systematically measure the rainfall characteristics, maize morphological characteristics and the throughfall in the whole growth period of maize, and the throughfall and its influencing factors in different growth periods of maize in western Liaoning was analyzed. The results showed that the throughfall increased with the increase of rainfall. Under the same rainfall, the throughfall in different growth stages presented the rule of jointing stage > maturity stage > tasseling stage. The throughfall rate decreased with the increase of maize LAI. The throughfall rate increased with the increase of rainfall intensity at jointing stage, but the trend was not significant at tasseling stage and maturity stage. The average throughfall rate of maize in the study area was 51.44%. The average throughfall rates at jointing stage, tasseling stage and maturity stage were 64.30%, 38.93% and 44.80%, respectively. The same influencing factor had different effects on throughfall rates at different growth stages of maize.

In order to study the effect of controlled drainage on soil fertility and emission loads reduction of rape/soybean field, plots planting experiments of three rapeseed/soybean with different controlled drainage treatments were carried out in Zhanghe Irrigation District of Hubei Province from 2018 to 2020. Soil samples at depth of 0~20 cm, 20~40 cm and 40~60 cm were collected for nitrogen and phosphorus analysis, drainage water quantity and quality were monitored and nitrogen and phosphorus emission loads were calculated. The results showed that compared with traditional FD treatment, controlled drainage FL and CL could cause total nitrogen losses at 0~20 cm soil and promote total nitrogen transfer to deep soil profile. The phosphorus retention capacity of controlled drainage FL and CL were better than that of FD, and the migration of total phosphorus to deep soil was not obvious. The effects of reducing nitrogen and phosphorus concentration and emission loads of FL treatment were significantly better than those of CL. Compared with FD, the concentrations of total nitrogen, nitrate nitrogen and total phosphorus of FL treatment had been decreased by 29.39%, 15.99% and 12.07%, and emission loads reduction reached to 73.93%, 68.98% and 67.54%, respectively. Controlled drainage treatment (FL) with a depth of 0.6 m at the outlet of underground pipe was a better drainage model for rape/soybean planting in Zhanghe Irrigation District.

Evapotranspiration model is an effective tool for estimating crop water demand, which provides important parameters for determining irrigation schedule and designing irrigation system, and helps agricultural industry to achieve the goal of water saving, high yield and high quality. There are many existing evapotranspiration models with different application conditions, which are not mature enough to be applied in the greenhouse environment. It is necessary to sort out the models and study the improvement methods of models in the greenhouse environment, so as to improve the accuracy of model estimation. In this paper, the main evapotranspiration estimation models and their applicable conditions were introduced. From the perspective of being applicable to the solar greenhouse environment, the methods of improving the Penman Monteith (PM) model were summarized. On this basis, the research trend of improving the accuracy of evapotranspiration model was pointed out, which enriched the research achievements in the field of crop evapotranspiration estimation in solar greenhouse. The analysis showsthat the PM model has the clearest mechanism and the most extensive application. The key to improve the PM model is to improve the parameters of surface resistance ( r_s) and aerodynamic resistance ( r_a). In addition, the improvement of crop coefficients ( K_c, K_{cb}, K_e) can also effectively improve the accuracy of model estimation.

The orifice of micro-sprinkling hose is difficult to measure and manufacture accurately because of its small size, so the hydraulic performance of single orifice has become the bottleneck of standardized design of micro-sprinkling hose. In order to predict the hydraulic behavior of orifice on micro-sprinkling hose accurately, a seamless steel tube with 32 mm inner diameter was used as the research object in this paper, and five standard orifices of 0.3, 0.4, 0.5, 0.6 and 0.7 mm were fabricated by precision laser drilling technology. The flow rate tests at 10 pressure levels were carried out, and the diameter-pressure-discharge model was established by cubic spline interpolation and polynomial fitting respectively, whose results were compared with the measured flow rates of 0.3, 0.35 and 0.54 mm orifices selected from an import micro-sprinkling hose. The results showed that the goodness of fit for the pressure flow formulas was very high based on the measured data of standard orifices of seamless steel tubes, whose determination coefficients were all more than 0.99. With the increase of orifice size, the flow rate of orifice was sensitive to the change of pressure, and the change degree was more severe at the lower pressure. The prediction accuracy of diameter-pressure-flow model obtained by cubic spline interpolation was generally better than that of polynomial fitting. The absolute relative error between the predicted flow rate and the measured value of the former was 0.46%~4.69%, while the latter reached 0.91%~5.35%, and the prediction accuracy of small sizes of 0.3 and 0.35 mm was better than that of large size of 0.54 mm. The pressure flow characteristics based on the orifices with standard size of seamless steel tube and the diameter-pressure-discharge interpolation prediction model obtained in this paper will provide technical support for the optimal design of micro-sprinkling hose products.

Aiming at the problems that the new advanced field efficient water-saving technology in the irrigation area of Xinjiang Construction Corps corresponds to low-level and extensive operation management, water delivery and distribution can no longer meet the irrigation needs of crops under the drip irrigation technology mode, the water demand of crops in the critical period cannot be guaranteed, and the drip irrigation technology is difficult to play its due benefits, in this paper, based on the hydrodynamic simulation of the channel, combined with the drip irrigation system required by typical crops such as cotton, red dates and corn, the channel optimization regulation model of the irrigation area based on the precise simulation of the hydrodynamic process of the water transmission and distribution system was established, and the finite volume method and genetic algorithm were used to solve the problem. The model has been demonstrated and applied in typical irrigation areas of the Corps. The results show that the channel optimization regulation model proposed in this study based on the accurate simulation of the hydrodynamic process of water transmission and distribution system can accurately simulate the channel water transmission and distribution process, and the water transmission and distribution plan formulated is efficient and reasonable, which can shorten the water distribution time, reduce the waste water and ensure the water demand of crops in the critical period. On this basis, this study put forward the optimal control mode of water transport and distribution in irrigated areas, and the corresponding control mode can be adopted according to the irrigation water demand in actual irrigation to provide the basis for each irrigation control in irrigated areas.

In order to improve the water shortage of apple tree in the Loess Plateau region and to accurately quantify the daily scale evapotranspiration of apple trees to guide orchard water management, the apple orchard in Majia Town, Chunhua County, Xianyang City was selected as the research object. The daily-scale evapotranspiration in an orchard are simulated by using the SW (Shuttleworth-Wallace) model with the soil moisture layer module, and the water use efficiency of the orchard was calculated. The results showed that the simulation results of the improved SW model and the measured values were R ²=0.78, RMSE=0.63 mm; the transpiration and evapotranspiration of apple trees increased first and then decreased from April to October, and the maximum transpiration of fruit trees was 46.64 mm in July. Water use efficiency (WUE) reached its peak in April, while WUE was low from May to September. The dry matter mass produced by transpiration and evaporation per unit of water (GPP) increased first and then decreased from March to October, reaching the maximum value of 32.11 g/m² in September. Overall, the SW model with the addition of soil moisture layer module can realize the simulation of daily scale evapotranspiration in orchards. Considering the changes of all indicators, the water supply should be ensured during the critical fertility period of fruit trees from June to August.

In modern agricultural irrigation, in order to obtain the flow rate of the open channel section, it is necessary to determine the velocity distribution of the open channel section first. However, most of the previous velocity distribution formulas are not accurate enough to meet the needs of precision irrigation. In this study, to solve this problem, on the basis of deducing the velocity distribution based on Tsallis entropy, the entropy parameters were rededuced, a new entropy parameter was proposed, the velocity distribution formula was further, and a two-point method was proposed to determine the velocity distribution of the section. The research method was verified by the measured data and numerical simulation software. The results show that: by measuring the velocity value u_c at one point on the center line of the section under the water surface and the velocity value u_z at another point under the same water depth, the two unknown parameters G_p and m_p in the velocity distribution formula can be calculated, and the transverse velocity distribution formula at the water depth position can be determined. Then the maximum velocity u_{\mathrm{m}\mathrm{a}\mathrm{x}} of the section is calculated by the known parameters, and the velocity distribution formula of the center line of the section is determined. Compared with the previous velocity distribution formula, the two-point method is simpler. This formula can be better applied in engineering practice, and has high theoretical significance and practical value.

Reasonable analysis of water use structure can predict water use conditions of future, thereby providing a basis for long-term water use security. Based on the water consumption data of agricultural industries in the nine provinces along the Yellow River and the secondary water resource zones in each province, the measurement of "green water" resources is added, and the evaluation methods such as equilibrium index, coefficient of variation, spearman rank correlation coefficient, and gray correlation analysis are used to evaluate the agricultural water use structure balance and its influencing factors in the Yellow River Basin. The results show that agricultural industries of the planting, forestry, animal husbandry (grassland) and animal husbandry (livestock) in the nine provinces along the Yellow River has large spatial differences in the balance of water use structure, and tends to be stable with time. The agricultural water use structure balance in the nine provinces along Yellow River considering "green water" resources has temporal and spatial variability, the irrigated area of arable land, the number of large and small livestock, "green water" resources, and irrigated area of forest and fruit fields are the strong influencing factors. The study points out that adjusting the strong correlation factor with poor equilibrium can improve the coordination between different water departments in the area.

The intelligent development of irrigated areas is indispensable for the new period of socialist modernization and is also crucial to the realization of agricultural modernization. Based on the intelligent development process data of relevant industries, the information development status survey data of 436 large irrigated areas and the measurement and control facility layout data of 124 typical irrigated areas, this paper summarizes the intelligent development characteristics of cities, transportation, agriculture, water conservancy and other intelligent development characteristics and defines the intelligent development connotation and construction structure of the irrigated areas through combined with the function characteristics of the irrigated areas under the new social and economic situation. It is pointed out that the present stage of intelligent construction of the irrigated areas mainly concentrated on the management platform and information perception of the irrigated areas and there exist some problems such as insufficient data, algorithm support, insufficient multi-specialty integration and cooperation, the lack of specialized operation and maintenance of information project and the lack of overall development ability. In the end, relevant measures and suggestions on the intelligent development of irrigated areas were proposed.