In order to reveal the effect of soil particle size on the transformation between shallow phreatic water and soil water during the freeze-thaw process,the freeze-thawing experiments of constant freezing temperature at -10,-20 and -25 ℃ successively for 62 days and natural thawing for 13 days were carried out in the laboratory,and the variation characteristics of phreatic water evaporation and recharge in homogeneous soil column with soil particle size of 0.1～ 0.5 mm ( A) ,0.5～ 1.0 mm ( B) ,1.0～ 1.5 mm ( C) ,1.5～ 2.0 mm ( D) and 2.0 ～ 2.5 mm ( E) under groundwater table depth of 0.5 m were analyzed. The results showed that the evaporation rate of phreatic water increased with the increase of soil particle size from 0 to 5 days under freezing,and the evaporation rate of phreatic water in soil column A,B,C,D, E was 0.15,0.20,0.24,0.29,0.34 mm/d,respectively. The accumulated phreatic water evaporation decreased exponentially with the increase of soil particle size during the freezing process,and the influence of soil particle size on phreatic water evaporation decreased with the decrease of freezing temperature. The recharge rate of soil water to phreatic water increased with the increase of soil particle size from 0 to 5 days under thawing. With the increasing of thawing time,the accumulated recharge of soil water to phreatic water decreased with the increase of soil particle size. The research results are significant for prevention of soil salinization and scientific evaluation of groundwater resources.

In order to explore the water-saving benefits of rice under different intermittent irrigation modes,taking Jianghuai Hilly area as an example,the influences of intermittent irrigation on various factors of rice in different stages of rice growth period were studied. The study was based on the trial which is divided into control group,short-term group and long-term group at Feidong agricultural water comprehensive test station in Anhui Province. The results showed that: ① Intermittent irrigation was beneficial to reduce water consumption in different periods, and the water consumption could be significantly reduced in long -term group; ② Intermittent irrigation could reduce the overflow loss, expand the storage space and improve the utilization rate of rainfall; ③ Intermittent irrigation could significantly reduce the amount of irrigation water,and the water-saving benefit of long-term intermittent irrigation was better,which could also increase production; ④In tillering and jointing stage,intermittent irrigation could save water by reducing water consumption and increasing rainfall utilization rate. In heading-flowering and maturity stage,water - saving benefits were produced by reducing water consumption. In this study,the proper intermittent time of rice was obtained,which had important reference value for improving the regional rice water-saving benefits.

In order to explore the tomato growth characteristics under different moisture content ( W) -zeolite amount ( Z) - buried depth ( H) ,the Logistic model was used to simulate the dynamic process of tomato growth,and the model simulation effect was evaluated. The effects of three factors on phenological parameters and growth parameters of tomato were further revealed. The results show that: the tomato S -shaped growth process under different treatments can be divided into three stages: increasing period,linear growing period and slowly increasing period. Logistic model is suitable for quantitative description of tomato growth process. The increasing moisture content or decreasing buried depth can advance the ending point t2 and decrease the length LGD of the linear growth period,promote the maximum linear growth rate MGR,average linear growth rate LGR and linear growth amount TLG. The effect of increasing W or decreasing H on starting point t1 is accelerative at first,and then inhibited. The effect of increasing Z on t2,LGD and TLG is accelerative at first,and then inhibited, whereas that on t1,MGR and LGR shows opposite trend. The effect of three factors on t1 is shown as Z ＞ W ＞ H,and that on t2,LGD,MGR, LGR,and TLG is shown as W ＞ H ＞ Z. The optimal treatment combination suitable for tomato growth is: 70% ～ 90% field capacity,zeolite amount 6 t /hm2,and buried depth 15 cm.

In order to reduce the verbosity growth at prophase and increase the 1000-grain weight and yield of film mulching spring wheat in Hetao irrigation area,the experiment took conventional irrigation stage as the control,the irrigation time of prophase growth period,i. e. tillering stage irrigation ( the first irrigation) and booting stage irrigation ( the second irrigation) was postponed by 10,15 and 20 d respectively,and the effects of prophase irrigation postponed on the soil moisture and the growth of film mulching spring wheat were monitored in Hetao irrigation area. The results showed that postponed prophase irrigation increased the soil moisture at flowering,filling and maturing stage; the later the prophase irrigation stage,the higher the soil moisture; the postponed prophase irrigation reduced the tillering ability, improved the ability of spike formation,reduced the number of infertility spikelet,improved grain numbers per spike,improved 1 000-grain weight and yield,and improved the soil water use efficiency and soil water production efficiency of film mulching spring wheat; among the different treatments,irrigation delay of 15 days at tillering stage and early booting stage had the best effect. The first and the second irrigation stage of film mulching spring wheat in Hetao irrigation area should be postponed at the joint-boot stage and the boot-head stage,i.e,about 15 days later than the conventional irrigation stage.

In this study,Ningqi No.1 wolfberry was used as experimental material to study the effects of water stress at different growth stages on fruit growth,yield and water use efficiency through different degrees of water stress treatment,so as to provide basis for accurate soil water management. The results showed that: the water stress significantly inhibited the single fruit fresh weight and the 100 kernel weight during the whole growth period,and the maximum drop of the single fruit fresh weight and the 100 kernel weight was 25.88% and 11.48% respectively compared with the control group; The fruit size of wolfberry was positively correlated with the degree of water stress,while the fruit shape index of wolfberry was not significantly affected by water stress; The effect of water stress on the yield and water use efficiency of wolfberry was extremely significant. Severe water stress treatment at any period during the entire growth period of wolfberry would cause a significant drop in yield,the maximum decrease in yield was 89. 26% compared with the control treatment,and WUE was only 0. 16 kg /m3 . Comprehensive Considering the indexes of fruit growth,yield and water treatment conditions,the optimal water stress treatment of wolfberry was determined as follows: soil water content in vegetation-growth stage,flowering stage and fruiting stage was maintained at 9.9% ～ 11.0% or 13.2% ～ 14.3%,and soil water content in autumn fruit stage was maintained at 13.2% ～ 14.3% or 9.9% ～ 11.0%.

In order to achieve real-time and accurate moisture prediction,a real-time moisture prediction model was established based on the soil moisture of cucumber and eggplant in the greenhouse of Shanxi Province Central Irrigation Experimental Station in 2018 and 2019. The experiment included two treatments of normal irrigation and halved irrigation,and real-time monitoring of soil moisture content in and out of the film was carried out by sensors. Based on the basic principle of water balance,the soil moisture content at the beginning of the period was taken as the independent variable,and the Taylor series was used to linearize the groundwater recharge and evapotranspiration,and a daily moisture prediction model was obtained. The soil moisture content prediction models,called model 1 and Model 2,were established respectively by using the data of one point moisture content in the film and the average data of two points moisture content in the film. The accuracy of the models was compared and analyzed,and the accuracy and applicability of the models were verified. The results showed that: ① The fitting accuracy and prediction accuracy of Model 1 were higher than those of Model 2; ② The prediction accuracy increased with the increase of the modeling series length ( 5,10,15 days) ,and the 15-day modeling series length had the highest prediction accuracy; ③ The model had good adaptability to different crops and different degrees of drought. The real - time moisture prediction model has strong applicability and high accuracy,and can be used for moisture prediction.

In order to more accurately determine the water and fertilizer management program for crops in the central arid region of Ningxia, using the way of point source infiltration,three factors,namely irrigation amount ( 3,5 L) ,droplet flow rate ( 0.5,0.75,1 L/h) and nitrogen concentration ( 0,200,500 mg /L) ,were set to carry out the study of soil water transport law under the condition of same droplet flow rate,different redistribution time and different nitrogen concentration. The results showed that: ① Under different redistribution time of the same droplet flow,when the redistribution time was shorter ( t was smaller than 3 days) ,the soil moisture content showed a decreasing trend with the increase of longitudinal soil depth. The soil moisture content decreased with the increase of horizontal radial distance under different redistribution time of the same droplet discharge. When the depth or horizontal radial distance of longitudinal soil layer exceeded 25 cm,the soil moisture content decreased faster. ② The redistribution time was significantly correlated with the longitudinal and radial soil moisture content,but the correlation of F1( 66.889 ) was larger than F2( 53.152) ,and the goodness of fit R2 1( 0.660 ) was larger than R22 (0.607) . ③ Under the same droplet flow and different nitrogen fertilizer concentration,the soil moisture content showed a decreasing trend with the increase of longitudinal soil depth or horizontal radial distance. When the depth of longitudinal soil layer was within the range of 0～ 25 cm,θF2 was the maximum value. In the range of 0～ 30 cm,θF1 was the maximum value. When the depth or horizontal radial distance of the longitudinal soil layer was greater than 25 cm,θFi decreased faster. In summary,within the range of 0 ～ 30 cm,the depth or horizontal radial distance of the longitudinal soil layer is 25 cm,which is the key node for the change of soil water content. This research result can provide technical support for the drip irrigation planting of Lycium barbarum in the arid region of central Ningxia.

Humic acids have been widely used in agricultural production and in the field of soil restoration. In order to study the influence mechanism of the application of humic acids on water infiltration in the field,this paper selected the weathering coal humic acids to conduct indoor water infiltration test. Four levels of humic acid concentration,soil bulk density and soil initial moisture content were selected for the test and a blank control test group was set up,the cumulative water infiltration was measured to analyze the influence of various factors on water infiltration. Based on the experimental results,the quantitative relationship between cumulative infiltration and influencing factors was constructed,and the quantitative relationship was verified and analyzed. The correlation coefficient between the measured value and the calculated value of the quantized relation was 0.9935,indicating that the quantized relation was feasible. Through the sensitivity analysis of the experimental factors,the results showed that the humic acid concentration,soil bulk density and soil initial moisture content were significantly negatively correlated with the cumulative infiltration quantity,and the infiltration time was significantly positively correlated with the cumulative infiltration quantity. The infiltration reduction effect analysis of humic acid showed that the infiltration reduction rate was 5.63%,indicating that humic acid had significant infiltration reduction effect on water infiltration. This study focused on the effect of humic acid on water infiltration process in order to provide reference for water resources regulation.

In China,the low efficiency of irrigation water use and the high occupancy rate of agricultural infrastructure are common problems in agriculture. In order to solve these problems,this paper constructed an optimal model for the design of irrigation channels and pipelines in farmland. The model can provide a new method for the design of irrigation channels and pipelines and provide a new idea for solving the contradiction between human and land and human and water in China. Based on python genetic algorithm,this paper established two optimization models aiming at the lowest construction cost and the maximum annual net benefit. Concrete trapezoidal channel,concrete U- shaped channel and PE pipeline were taken as the subject investigated. Based on the established model,this paper explored the feasibility of the model and the optimal combination of irrigation channel and pipeline in farmland by taking the channel planning and regulation project of Linhai Farm in Jiangsu Province as an example. The results showed that: ① the model,based on python genetic algorithm,could optimize the design of irrigation channel and pipeline with fast calculation speed and high precision. ② The use of trapezoidal bucket and trapezoidal agricultural canal could significantly reduce annual investment cost by about 40% and ensure the positive annual net benefit ( P＜0.05) . The use of agricultural management can significantly increase more than 10% of the new arable land. ③ The combination of trapezoidal brackets canal and agricultural pipes and u-shaped brackets canal and agricultural pipes had a great annual net benefit,both exceeding 60 000 yuan / year,which was 10% more than that of other combinations. This method can be used as the optimal combination of field irrigation canal systems in practical projects.

In Hetao irrigation area of Inner Mongolia,the effects of different irrigation modes on the quality of wolfberry were studied by setting four rotational irrigation schemes with Brackish and Fresh Water and taking local irrigation mode as the control. The results showed that the 100-grain weight and fruit length of fresh fruit were significantly negatively correlated with the soil electrical conductivity,and reached the maximum value when the soil salt was 1.23 mS /cm,which was 18.90 mm and 67.09 g,respectively. Therefore,T3 treatment was conducive to the improvement of the commercial quality of wolfberry,thus increasing the yield. The contents of amino acids, polysaccharides and total sugars were significantly positively correlated with the soil electrical conductivity,and reached the maximum value when the soil salt was 1. 54ms /cm,which was 11. 800%,67. 257% and 7. 821 mg /100 mg,respectively. Therefore,T4 treatment was conducive to the improvement of medicinal quality of wolfberry.

In order to study the effects of no-tillage and manure on soil water and wheat yield in dryland in southern Shanxi Province,the influence of no-tillage and manure on soil water storage,water consumption,water use efficiency and yield of wheat were studied under long -term experiment. Four treatments including no tillage with fertilizer ( NT) ,deep tillage with fertilizer ( T) ,no tillage with chemical fertilizer and organic fertilizer ( NTM) ,deep tillage with chemical fertilizer and organic fertilizer ( TM) were set up in the experiment. The results showed that: the soil water storage in 0～ 100 cm soil depth before sowing in NT and NTM treatment were 39.58 and 46.56 mm higher than that of T treatment,because of the significant increase of soil water storage in 50～ 100 cm soil depth. The soil water storage efficiency were NTM＞NT＞TM＞T in 0 ～ 100 cm soil depth during growth period,and the water storage efficiency ratio of the first three treatments was significantly increased by 22%,16.06% and 11.5%,respectively,than that of T treatment. Soil water storage consumption in 0～ 100 cm soil depth were NTM＞NT＞TM＞T,and there were no significant difference among soil water storage consumption in 0 ～ 50 cm soil depth among four treatments,but the consumption of NTM and NT treatment in 50 ～ 100 cm soil water storage was significantly higher than that in T treatment. The yield and water use efficiency in NT treatment were 26. 71% and 1. 66 kg /( hm2 ·mm) higher than that of T treatment, respectively. Therefore,no-tillage can improve the yield and water use efficiency of winter wheat in dry land,but the combination of no- tillage with organic fertilizer and chemical fertilizer should be applied rationally in combination with precipitation to achieve high and stable yield and efficient utilization of water and fertilizer.

In order to solve the problem of improper setting of neutron source location and energy spectrum in the calculation of soil moisture measurement calibration function based on MCNP or URANOS models,PLANETOCOSMICS based on Geant4 was proposed to calculate the neutron spectrum of cosmic ray under different conditions. The differences of these results were analyzed to obtain the reasonable neutron source incident height and energy spectrum. A new calibration function calculation model based on these rational neutron source settings was established. The results show that: ①The cosmic ray neutron source used in model should be set at altitude above 600 m. ②Through the comparative analysis of backscattered neutron spectrum and 10-8 ～ 10-4 MeV calibration function,the calculation results of Geant4 model are better than those of URANOS and MCNP. ③Neutron in the 10-6 ～ 10-2 MeV energy range at altitude 2 m is more sensitive respond to the variation of soil moisture,which is better than 10-8 ～ 10-4 MeV energy range. Therefore,the calibration function in the energy range 10-6 ～ 10-2 MeV calculated by this model is suitable for real-time measurement of soil moisture by cosmic ray neutrons.

Applying chemical improvers and biochar is an important way to improve soil and farmland water availability. A thorough understanding of the effects of chemical improvers and biochar on soil water movement is the basis for improving soil and water conservation conditions and increasing farmland water availability. An indoor purple soil column experiment was conducted to study the effect of different amounts of biochar on soil water infiltration under appropriate hydroxypropyl methyl cellulose( HPMC) conditions. The results showed that: ① under the condition that no HPMC was added and the content of biochar added in the purple soil was 0,2%,4%,the difference of soil infiltration was not significant; when appropriate HPMC was applied,both 2% and 4% biochar could significantly reduce the infiltration rate compared with that without biochar addition,but the difference in the mitigation effect was not significant,and the difference in the absorption rate was not significant. ② After the infiltration rate stabilized,the wetting peak distance decreased with the increase of HPMC and biochar. The addition of 0.3 g /kg HPMC and 4% biochar to the purple soil had the most obvious inhibitory effect on the water infiltration process,but the difference was small when the content of biochar and 2% biochar were added,and there was no significant difference in the absorption and infiltration rate between the two..

In order to study flow resistance and flow regularity of solenoid valve chamber in the irrigation and drainage pipe network system, two kinds of solenoid valve chamber DN110 and DN125 were discussed by test methods. At the same time,the RNG k-ε were adopted to analyze and verify the flow fields for two kinds of solenoid valve chamber by using numerical simulation. Comparing the experimental results and numerical results,the simulation resistance coefficients of DN110 and DN125 solenoid valve chamber were in agreement with the experimental data. And other five kinds of solenoid valve chamber DN63,DN75,DN90,DN140 and DN160 were studied by numerical simulation. Based on the numerical calculation results,the relationship between the local resistance coefficient of the solenoid valve chamber and the pipe diameter was obtained. And it was found that the resistance loss of the solenoid valve chamber was mainly the water energy dissipation caused by the vortex in the valve chamber and the downstream pipeline,the internal turbulence of the water flow,and the impact of the water flow on the side wall.

The contradiction between supply and demand of agricultural water resources is particularly prominent in China. Rational utilization of reclaimed water is the trend of agricultural irrigation in China. Based on a large number of domestic and foreign literatures about the relevant research of Reclaimed water drip irrigation,the research status and development of reclaimed water drip irrigation were systematically analyzed from four aspects: the layout of reclaimed water drip irrigation system,the formation and mitigation mechanism of reclaimed water drip irrigation system obstruction,the spatial and temporal distribution and environmental behavior of typical pollution factors,and the nutrient absorption mechanism of crops under the condition of reclaimed water drip irrigation. At the same time,based on the current research progress,the research focus and development of reclaimed water drip irrigation were prospected from the three aspects of experimental research direction,experimental design method and data analysis method,aiming to provide a certain degree of theoretical basis and suggestions for future reclaimed water drip irrigation research.

Brackish water resources have great potential for development and utilization. Using brackish water resources to replace part of fresh water for farmland irrigation has become an important way to alleviate water resources crisis. However,the security problems brought by brackish water irrigation have always been the focus and difficulty of research. This paper analyzes the factors affecting the safe irrigation of brackish water,summarizes the previous research results,and summarizes the safe irrigation mode of brackish water from two aspects: irrigation mode and irrigation method. Then,combined water and salt monitoring and numerical model,the paper summarized the research on precise security irrigation based on brackish water quality standards,expounded the farmland regulation measures to solve the problem of soil security under brackish water irrigation and summarized the future research trend of brackish water irrigation safety to promote the brackish water safety efficient utilization and farmland irrigation.

The modernization of irrigation area is the basic guarantee of food security in China. In 2025,we will strive to build a batch of modern irrigation districts with“water saving and high efficiency,complete facilities,scientific management and good ecology”,which is the basis for realizing the strategy of Rural Revitalization and promoting agricultural modernization. This paper first reviewed the definition and connotation of the modernization of irrigation area in China,and proposed to realize the modernization of irrigation area by building safe irrigation area,water - saving irrigation area,green irrigation area and digital irrigation area. At the same time,on the basis of the characteristics of the modernization of irrigation area,the evaluation index layer of irrigation area modernization was put forward by using AHP. The index layer includes 24 modern evaluation indexes in six categories,including safety guarantee,agricultural irrigation and drainage,management and service,ecological environment,information construction and efficiency and benefit. Taking the Dongfengqu irrigation area of Hubei Province as an example,the evaluation index system was used to evaluate comprehensively in different years. The evaluation results show that the modernization evaluation system of irrigation area can effectively evaluate the development level of Dongfeng canal irrigation,guide the modernization development of irrigation area,and provide decision-making basis for the modernization construction of irrigation area.

As the main food producing area in China,the risk of drought in the Huang-Huai-Hai Region increases under the trend of climate warming. It is of great significance to analyze the distribution of drought in Huang-Huai-Hai region on how to better cope with agricultural production under the situation of water resources shortage. Based on the principle of agricultural drought,this paper selects the index system of precipitation,topography and landform to construct the drought zones division index system,and uses the K-means clustering method to carry out the drought zones division in the Huang-Huai-Hai area. The results show that the Huang-Huai-Hai area is divided into very light, light,middle,heavy and heavy drought areas; the closer the geographical location is to the inland,the higher the terrain is,the more serious the drought conditions are. Moreover,the spatial distribution of drought conditions in Shandong and Henan provinces is quite different. Promoting different drought management in different areas of Huang-Huai-Hai can enable more targeted investment of drought resistance resources and reduce drought losses.