Understanding the spatial distribution of soil moisture, salinity and pH value in the gravel-sand mulched field under different irrigation methods can effectively improve the utilization efficiency of brackish water. In this study, the spatial variation characteristics of soil conductivity, moisture content and pH value of 0~40 cm soil layer of drip irrigation and micro-sprinkler irrigation were compared and analyzed by field sampling, classical statistics, geostatistics and Kriging interpolation method. The results showed that the average conductivity and discretization degree of soil in 0~20 cm soil layer under micro-sprinkler irrigation were lower than those under drip irrigation. At the same time, the spatial distribution of 0~20 cm and 20~40 cm soil conductivity under the two irrigation methods showed moderate variation and strong spatial correlation. The average electrical conductivity of 20~40 cm soil layer was less than that of 0~20 cm soil layer. The soil moisture content of micro-sprinkler irrigation was slightly lower than that of drip irrigation, and the soil moisture content of 0~40 cm soil layer was medium variability and had medium intensity spatial correlation. Regardless of micro-sprinkler irrigation or drip irrigation, the soil conductivity of the surveyed plots showed that the middle position was low, and the ground edge was high. The soil moisture content was high in the middle and low at the ground edge. The influence of irrigation mode on soil pH was not significant, and its spatial variability was weak, but pH value had a strong spatial correlation under micro-sprinkler irrigation. Under brackish water irrigation, the accumulation of salt in the surface soil was inhibited by mulched sand-gravel, and there was a phenomenon of accumulation towards the edge of the uncovered land. There were moderate variability and spatial correlation in soil salinity and water in the gravel-sand mulched field under different irrigation methods, while the spatial variability of pH was weak. The results of this paper can provide a theoretical basis for the rational utilization of brackish water in the gravel-sand mulched field.

In order to explore the effects of different concentrations of fertilizer on the characteristics of wet body and the law of water migration during the interinfiltration of two point sources in bubbled-root irrigation, four fertilizer concentrations (mass concentrations) (0, 5, 10 and 20 g/L) were set up in Yuanzhishan test base of Northwest A&F University in northern Shaanxi Province to investigate the effects of fertilizer concentrations on soil cumulative infiltration and soil moisture content. The results showed that under the same concentration of fertilizer solution, the cumulative infiltration at free infiltration was greater than that at intersection infiltration, and the cumulative infiltration at bubbled-root irrigation intersection had a significant power function relationship with time and the concentration of fertilizer solution (R ²>0.9, P<0.01). Both Philip model and Kosyiakov model could be used to fit the infiltration process of two-point bubbled-root irrigation. The higher the concentration of fertilizer solution, the higher the imbibition rate S, and the stronger the infiltration capacity of soil. The concentration of fertilizer liquid increased the cumulative infiltration of the two-point source surging bubbled-root irrigation. Compared with the single point source surging bubbled-root irrigation, the cumulative infiltration of the two-point source surging bubbled-root irrigation decreased, but the soil moisture content at the intersection increased. In the case of dual point source intersection infiltration, the variation difference of soil moisture at different locations was less than that at the free infiltration side, and the higher the concentration of fertilizer liquid, the deeper the moisture depth at the intersection surface, and the soil moisture content was greater than that at the free infiltration side. In the actual irrigation process, too large concentration of fertilizer will not be conducive to the improvement of water and fertilizer utilization efficiency. Therefore, in the process of field layout, a reasonable two-point source arrangement can improve the irrigation efficiency of the bubbled-root irrigation more effectively and improve the utilization rate of water resources.

Soil erosion is the main cause of ecological environment deterioration and land productivity decline, while slope, rainfall intensity, rainfall and land use type are important factors affecting soil erosion. Qilong Bay small watershed is dominated by mountain brown soil. Based on the observed data of 10 runoff plots in Qilong Bay from 2008 to 2016, soil erosion factors and erosion amount were analyzed, and suggestions were put forward for soil and water conservation measures of brown soil. The results are as follows: ① Slope has no significant effect on soil erosion in Qilongwan watershed of Laiwu. ② In each rainfall variation range, soil erosion increases with the increase of slope, and the reason for soil erosion is not a single increase or decrease, which may be related to the sputtering rate. ③ The soil erosion amounts of the three types of runoff plots are in the following order: cultivated land plot > bare land plot > forest plot. ④ When the rainfall intensity and rainfall amount are small, there is no need to take erosion control measures on a large scale; when the rainfall intensity or rainfall amount is large, the soil conservation measures of chestnut combined with fish scale pits are more effective. ⑤ The higher the vegetation coverage, the smaller the soil erosion; the lower the vegetation coverage, the greater the soil erosion.

In order to further improve the prediction accuracy of precipitation in response to the non-linear and difficult-to-predict nature of hydrological time series, the complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and Temporal Convolutional Network (TCN) coupling model was proposed. Based on the monthly precipitation data of Henan province form January 1960 to July 2000, the monthly precipitation from August 2008 to December 2017 was predicted. The model used CEEMDAN to decompose the original unstationary precipitation sequence into a set of relatively stationary subsequence components, then predicated each subsequence component with TCN model. Finally the prediction result of subsequence components were superimposed to obtain the final results. In order to verify the effectiveness of the model, the model was compared with LSTM, TCN, and CEEMDAN-LSTM models. The results show that the CEEMDAN-TCN model proposed in this paper has the highest prediction accuracy, with 42.82%, 35.65%, and 18.12% reduction in RMSE and 37.75%, 27.53%, and 19.39% reduction in MAE, respectively, compared with the three comparison models. In the space distribution, the predicted values of the CEEMDAN-TCN model by using Ordinary Kriging interpolation are similar to the space distribution of the actual values. In summary, the CEEMDAN method can effectively reduce the nonstationarity of monthly precipitation data, and the combined model coupled with the CEEMDAN method has higher prediction accuracy than a single model; the CEEMDAN-TCN model proposed in this paper has different degrees of improvement in prediction accuracy compared with the three comparison models, and the method combines the CEEMDAN signal decomposition technology, deep learning model and the field of precipitation prediction, which effectively improves the monthly precipitation prediction accuracy.

Root length density distribution is an important indicator of the potential water use status of crop roots. However, current studies on the quantification of crop roots under water and salt stress are limited. Based on this, using sunflower in saline farmland from 2016 to 2017 as the research object, this paper presented a comparative analysis of the changes in soil water salinity and crop root length density distribution in different salinity plots (S1, S2 and S3), proposed a logistic model (LRDG) that can characterize its dynamics, and quantified the model parameters (α and β). The results showed that the overall crop root length density in high-salt plots was higher than that in low-salt plots, and the phenomenon of concentrated root growth was significant, especially after the bud stage, sunflower roots were concentrated in the 30~75 cm soil layer, and the cumulative root length accounted for more than 40%, among which the peak crop root length density reached more than 5 cm/cm³ in the S3 plot in 2016. Compared to the exponential and power function models of standard root length density, the logistic model can better characterize the static root length density distribution of sunflower in saline farmland with R ² of 0.870 and RRMSE of 0.338. Meanwhile, the logistic model parameters α and β vary significantly with soil surface water salinity and cumulative temperature, thus this paper specifically quantified the formulae for the parameters α and β, RRMSE is 0.425 and 0.297,respectively.This indicates that the constructed LRDG model can accurately characterize the dynamic response of crop root length density distribution under soil water and salt stress, and can provide tools to support the exploitation of stress resistance potential and scientific management of water and fertilizer in saline farmland.

Taking the slope in the front mountain area of the Manas River basin in northern Xinjiang as the research background, the effects of different slopes and directions on the soil water infiltration and evaporation process of the slope surface and the water retention capacity of different mulches (black film and white film) on the slope were studied by indoor simulation experiments. The results showed that with the increase of the daily radiation duration and radiation intensity, the daily relative decrease of soil moisture content in the evaporation process also increased, and the response of the upper 20 cm soil layer to the change of radiation intensity was the most obvious; After covering the slope, the water retention of the black film was better than that of the white film, and the steeper the slope, the smaller the effect of covering on the overall water retention of the slope. The research results will provide theoretical basis for the ecological functions of water conservation and soil conservation in the northern slope area of Xinjiang.

As the largest cotton producing area in China, drip irrigation technology of cotton field has been basically mature and widely used. At present, the control methods of drip irrigation system of cotton field mainly focus on PID control algorithm and fuzzy control algorithm, but the traditional PID algorithm is easy to cause overshoot, and the parameters of fuzzy algorithm are mostly set based on manual experience, which makes the control not delicate. Aiming at these problems, this paper designs a control system based on GA-Fuzzy-PID algorithm, which combines the characteristics of simple calculation, strong function and good optimization effect of Genetic Algorithm. By changing the frequency of the frequency converter connected with the hose pump, the fertilization flow rate at the outlet of the hose pump is precisely adjusted. The numerical simulation of PID algorithm, Fuzzy-PID algorithm and GA-Fuzzy-PID algorithm under different flow settings is compared with the experiment result when the flow is set at 0.6 m³/h. The results show that the maximum overshoot and steady state time of GA-Fuzzy-PID controller are obviously shortened, and the GA-Fuzzy-PID controller has better control effect and can meet the requirements of precise control of fertilization and irrigation system.

In order to deeply understand and improve the current situation of surface water quality in Chengde, and realize the ecological sustainable development of the research area, the CCME WQI water quality evaluation method and main component analysis were used to discuss water pollution source and conduct the correlation analysis of main agricultural non-point source pollution index. The study objects were four main tributaries in the region. The test results of river water quality showed that TN concentration exceeded the standard by 2.25~12.8 times, and the concentration of fecal coliform, TP and COD exceeded the class III standard of surface water in some sections. The results of CCME WQI water quality assessment on the upper and lower sections of Liuhe River were basically stable in the range of 80.74~89.00. The source pollution problem of Wulie River and Yishun River was aggravated in recent years. The single factor evaluation result of water quality category was basically in line with the target water quality of water function area. It was preliminarily determined that the main pollution sources were domestic sewage or farmland farming, rainfall runoff, plankton growth and reproduction, and oil leakage; there was a significant negative correlation between the concentration of main agricultural non-point source pollutants and the water quality evaluation results in Pu River. The reduction of agricultural fertilizer application and livestock and poultry manure in Pu River had a positive impact on the water quality evaluation results. However, urban sewage was still the main source of pollution contribution to the Yixun River, Wulie River, Liu River and Pu River. In recent years, the water quality of the main tributaries of Chengde has improved, but the problem of water pollution still exists, and the tributaries have different pollution status under the influence of geographical conditions and land use. Therefore, it is necessary to actively promote the special management of each tributary, build urban underground municipal pipeline system, reform modern sewage treatment technology plant, and strengthen the supervision and management of industrial enterprises. It is suggested to conduct intensive farming, scientific restrictions on the proportion of agricultural fertilizer and standardizing the mode of livestock and poultry breeding to promote the historical process of socialist modernization and ecological civilization construction in Chengde area.

In recent years, the citrus industry has developed into one of the agricultural and economic pillar industries in the hilly areas of Southwest China. After exploring the effects of different water and fertilizer management conditions on citrus yield, it is necessary to conduct crop model research for citrus fruit trees in order to apply them more widely to different regions. The feasibility of simulating crop growth using the WOFOST model has been widely recognized. Parameter calibration of the model based on data collected from field experiments can improve the accuracy of the model's simulation of citrus, and thus provide better guidance for production practices. In this study, drip irrigation water and fertilizer control experiments were carried out for different growth stages of citrus from 2021 to 2022. The EFAST method was used to analyze the sensitivity of 25 parameters required for simulating leaf area index (LAI) and yield by WOFOST model, such as leaf growth, CO₂ assimilation, assimilate conversion and leaf nutrient content. The PEST software was used to optimize the highly sensitive parameters, and the field experimental data were used to validate the LAI and yield simulated by the model. The results showed that the sensitive parameters for simulating LAI and yield by the model were similar, including maximum relative growth rate of LAI, specific leaf area, single leaf CO₂ assimilation efficiency, leaf assimilate conversion efficiency, initial root length. The difference was that LAI simulation was sensitive to stem assimilate conversion efficiency, thermal time and other parameters, while yield simulation was sensitive to maximum potassium concentration of leaf dry matter. Based on the optimal parameters calibrated by 2021 data, R ² between simulated values and measured values of LAI _m under different irrigation management was 0.580 0，NRMSE was 15.10%，R ² between simulated values and measured values of yield was 0.647 1，NRMSE was 6.81%. The validation with 2022 data showed that HWMF treatment during fruit expansion period had the highest simulation accuracy. R² between simulated values and measured values of LAI _m under various treatments during fruit expansion period ranged from 0.472 6 to 0.849 2，NRMSE ranged from 13.09% to 15.26%，R² between simulated values and measured values of yield ranged from 0.406 3 to 0.702 2，NRMSE ranged from 6.33% to11.33%. This study showed that WOFOST model achieved high simulation accuracy at field scale after calibration, and can be used to carry out quantitative analysis of the impact of different irrigation management methods on citrus growth.

In order to simulate soil moisture dynamics of storage pit irrigation orchards and achieve soil moisture dynamics prediction, a stratified water balance model for 0~200 cm soil layer under storage pit irrigation conditions was established based on the water balance principle of soil, by introducing the local irrigation coefficient \xi based on the existing stratified water balance model and correcting the infiltration water in the 0~70 cm soil layer where the storage pit was located. From April to October 2015, a water dynamic monitoring experiment was conducted for two water treatments (treatment 1 with upper and lower limits of irrigation of 50%~80% of field water holding capacity, treatment 2 with upper and lower limits of irrigation of 60%~90% of field water holding capacity) of water storage pit irrigated orchards at the Fruit Tree Research Institute, Academy of Agricultural Sciences, Taigu County, Jinzhong City, Shanxi Province. The data from treatment 1 were used to rate the local irrigation coefficient \xi of the model, and the rate value of \xi was obtained as 0.8. The data of treatment 2 were used to validate the model after the rate, and the maximum root mean square error of the model was 0.007 4 cm³·cm^-3, the maximum average relative error was 2.80%, and the maximum average absolute error was 0.006 4 cm³·cm^-3, indicating that the model had high simulation accuracy and the stratified water balance model could be used to simulate the soil moisture dynamics of the water storage pit irrigated orchard. The simulation results of the moisture dynamics of the two water treatments showed that the soil moisture content of each layer tended to decrease over time due to evaporation, water infiltration, root absorption and other water consumption factors, and tended to increase when there was irrigation and rainfall, and the overall soil moisture content fluctuated within a certain range. After irrigation and rainfall, the increase of soil water content in each soil layer from shallow to deep showed different trends. The increase of soil water content in each soil layer increased and then decreased with depth after irrigation, while the increase of soil water content in each soil layer decreased with depth after rainfall. Compared with the middle layer and the lower layer, the fluctuation range of the soil moisture content of the upper layer was greater and the average moisture content of this layer was lower. The average water content of soil in all layers of treatment 2 was higher than that of treatment 1.

In response to the lack of snow cover in cotton fields during the winter fallow period in southern Xinjiang and the scarcity of agricultural water resources, local governments often choose winter and spring irrigation to regulate the soil moisture before sowing in cotton fields. In existing studies, spring irrigation and drip irrigation have shown good effects on salt leaching and soil moisture control during the fallow period. This experiment compared and studied the changes in water and salt characteristics before and after irrigation with three control measures, including winter irrigation flood irrigation, winter irrigation drip irrigation with different irrigation quotas, and winter irrigation drip irrigation with dry sowing and wetting. The study explored the impact of different soil moisture control measures on soil moisture before and after sowing in cotton fields and identified appropriate irrigation thresholds before and after sowing to provide moisture protection for the later implementation of dry sowing technology. Compared with other control measures, the control measures of high quota winter drip irrigation have a more stable soil moisture content in the 40~60 cm soil layer before sowing and a more uniform distribution of soil moisture. Under the condition of low water consumption, there is little difference in soil moisture content between the measure of winter irrigation drip irrigation with dry sowing wet discharge with irrigation quota of 600 with 225 m³/hm² and the measure of winter irrigation drip irrigation with irrigation quota of 1 200 m³/hm², and the average moisture content of the former is slightly higher. The soil moisture content of the measure of winter drip irrigation with dry sowing and wet discharge with irrigation quota of 1 200 with 225 m³/hm² is more balanced and stable compared to that of the measure of winter flood irrigation. After winter irrigation regulation, the average soil salt content significantly decreases, and the higher the winter drip irrigation quota, the more thorough the salt leaching. Compared with winter drip irrigation, the control measures of winter drip irrigation with dry sowing and wet release show a significant difference in the average salt content of the 0~40 cm soil layer. Compared with other measures, the effect of washing and suppressing soil salt is better. In summary, the regulation of soil moisture during the off crop period has a positive effect. The measures of winter irrigation drip irrigation with dry sowing and wet discharge regulation have a higher average moisture content in each soil layer on the basis of water-saving, and their soil salinity and water environment are more suitable for cotton germination, which in turn affects the preservation and subsequent growth of cotton seedlings.

In order to obtain a set of better anti-clogging water quality treatment schemes under aeroponic cultivation conditions, this paper compared different water quality treatment schemes to analyze the effect of water quality treatment on the clogging of aeroponic irrigation emitters and tomato growth and development. The water treatment methods included T1, magnetized water treatment, T2, inorganic acid (dilute hydrochloric acid) acid treatment, and T3, organic acid (food-grade citric acid) acid treatment. The concentration of nutrient solution, which was expressed by the electrical conductivity (mS/cm), was adjusted according to different growth and development stages of tomato, as 0.8~1.0 mS/cm in seedling stage, 1.4~1.6 mS/cm in flowering and fruiting stage, and 2.2~2.4 mS/cm in full fruit stage. The plant height, stem diameter, leaf area and daily flow of atomized emitter were recorded regularly during the experiment. The quality of tomato fruit was monitored after the second fruit ripened. The results showed that with the increase of nutrient solution concentration and time, the blockage degree of atomizing nozzle showed a growth trend of ' fast-slow-fast '. T1, T2 and T3 treatments showed certain anti-clogging effects on atomizing nozzles at three nutrient solution concentrations. The effects of T1 and T2 were similar, and the effect of T3 was poor. All the three water quality treatments had positive effects on the growth of tomato plants at seedling stage and flowering and fruiting stage, and T3 treatment had the best effect. T2 and T3 treatments showed inhibitory effects on the growth of tomato plants at full fruit stage. T1 treatment significantly improved the size and quality of tomato fruit, while all the three treatments had no significant effect on nutrient content of tomato fruit. Considering comprehensively, the anti-blocking water treatment should be based on magnetization treatment and supplemented by appropriate citric acid at the seedling stage, which is the most conducive to the anti-blocking of atomization nozzle and the growth of tomato.

In order to investigate the movement of water and solute in the surface and soil under precipitation conditions, the two-dimensional diffusion wave equation and the traditional three-dimensional Richards equation were used to describe the surface runoff and soil water movement respectively, and the dual node approach was chosen to couple the two ones. According to Darcy's law and solute concentration of surface water and soil water, solute exchange capacity of surface runoff and soil water was calculated, and a fully coupled numerical model of water movement and solute transport in surface and soil was constructed. Physical model experiments from the published literature were selected for numerical simulation tests. In Example 1 and Example 2, the average relative error between the numerical simulation results of surface runoff and the experimental results of the model were less than 14.8% and 21.5%, respectively, and the root mean square error were less than 0.147 cm²/s and 0.833 cm²/s, respectively. The mean relative error between the numerical simulation results and the experimental model results for runoff nitrate concentrations in Example 2 was less than 24.7% and the root mean square error was less than 1.334 mg/L. The comparative analysis of surface runoff and solute concentration data obtained from physical experiments and numerical simulations verified the reasonableness and accuracy of the model in this paper. The results of the study can provide theoretical support for the analysis of coupled water movement and solute transport in surface water and soil water.

In order to explore the characteristics of soil preferential flow in different grazing management grasslands in semi-arid areas, the desert steppe in central Inner Mongolia was taken as the research object, through field simulation staining tracer test, combined with computer image processing technology, the development characteristics, development degree and influencing factors of preferential flow were systematically studied and the effects of different grazing management on grassland water solute transport were analyzed in order to provide theoretical data support for vegetation restoration and soil and water conservation in semi-arid grassland. The results showed that: ①The spatial heterogeneity of soil water infiltration depth in different grazing management grasslands was strong, the water infiltration depth of forbidden grassland was the largest, the peak-trough alternating distribution structure was obvious, and the heterogeneity of infiltration water flow was strong. ②There were preferential flow phenomena in different grazing management grasslands, but there were differences in degree and type, uniform substrate flow was mainly distributed in the surface soil, and the development degree of preferential flow in forbidden grazing grassland was the highest. ③Soil mechanical composition was the core factor affecting the formation and development of soil priority flow in grassland under the management of semi-arid areas. In summary, in the semi-arid grassland area, the no-grazing grassland has a greater soil moisture infiltration depth and preferential flow effect, which can effectively increase water and nutrient transport, reduce surface runoff and nutrient loss, and can be used as a sustainable grazing management practice in semi-arid grassland area.

The integrated technology of water and fertilizer in high-efficiency water-saving irrigation has been rapidly promoted and widely applied due to its characteristics of water saving, fertilizer saving and high efficiency. In this paper, the current situation of water and fertilizer integration technology mode of high-efficiency water-saving irrigation in China was expounded firstly. Then, the effects of water and fertilizer integration technology of high-efficiency water-saving irrigation on maize yield, water and fertilizer utilization efficiency were briefly reviewed. The main problems existing in the water and fertilizer integration technology of high-efficiency water-saving irrigation were analyzed. The corresponding countermeasures were put forward and the direction of further attention in the future was prospected, in order to provide technical reference for improving the application of water and fertilizer integration technology in efficient water-saving irrigation of maize.

In order to realize the use of hydropower in pipelines to meet the power supply needs of intelligent irrigation systems, it is necessary to improve the power generation and power generation efficiency of ultra-micro turbines. This study used Design Modeler and Soildworks to build a three-dimensional structural model, grouped different blade numbers and blade angles of the hydraulic turbine runner and imported them into the fluid dynamics simulation software Fluent for analysis. According to the characteristics of irrigation water, the simulation experiment was conducted under the conditions of water pressure of 150 kPa and water flow speed of 1.33 m/s. Under the condition of stable rotation, the simulation tests were carried out on the stabilized rotational speed of the impeller models with blade numbers of 6, 10, 20, 25, 30 and angles of 60°, 70 °, 75°, 80° and 90°, respectively. It was found that under the angle of 75°, the rotational speed of the turbine with 20 and 25 blades was faster, as 1 185 r/min and 1 148 r/min, respectively. Through simulation test, it was found that the relationship between impeller speed and blade length was not obvious. Through the analysis of the effective output power and flow field, it was found that the optimal combination in the simulation experiment was 25 blade number with 75° angle. It is concluded that when the number of blades is 6~20, the rotational speed increases with the increase of the number of blades, while it will drop sharply under 20~30 blades; when the angle of the blade is 75°, the rotational speed is the highest; the blade length has little effect on the rotational speed. Through adjusting the number of runner and the angle of blade, the speed of impeller can be significantly improved, the output power can be effectively increased and the power generation efficiency can be improved.

In order to study the effect of drip irrigation amount and method on wine grape quality, in this study, the 9 a raw wine grape Cabernet Sauvignon was selected as test material, split zone design was adopted, and three irrigation rates [1 800 m³/hm² (A1), 2 700 m³/hm² (A2), 3 600 m³/hm² (A3)] were used as main zones. Three drip irrigation methods [one row, one tube (B1), one row, two tubes (B2) and alternate zone irrigation (B3)] were used as sub-areas. The TOPSIS model based on subjective and objective combination weights was used to comprehensively evaluate the quality of wine grapes, and the effects of different irrigation rates and drip irrigation methods on the quality of 18 wine grapes were studied. The results showed that different drip irrigation amounts had significant effects on the appearance quality (longitudinal diameter, transverse diameter and fruit weight), which increased first and then decreased with the increase of irrigation amount. The intrinsic quality (tannin, anthocyanins, anthocyanins, total phenols and flavonoids contents) increased first and then decreased with the increase of irrigation amount. The total sugar content decreased with the increase of irrigation amount, and the total acid content increased with the increase of irrigation amount. The effect of drip irrigation on appearance quality and internal quality was not significant. There is some interaction between irrigation quantity and drip irrigation. It can be concluded that the optimal technical parameters of drip irrigation were selected as irrigation quantity of 2 700 m³/hm² and combination of one-line and two-pipe treatment of drip irrigation.