Plow pan has an important influence on the movement and distribution of soil water and salt. To explore the influence of bulk density of plow pan on the movement and distribution of soil water and salt under mulched drip irrigation with brackish water，different scenarios were simulated by HYDRUS-2D. After analyzing the variability and statistical characteristics of soil water and salt，and the discharge rates and accumulated amounts of discharged water and salt at the bottom of the model，the following results were drawn. The larger the unit weight of the plow pan， the stronger the water retention capacity of the tillage layer and plow pan，the smaller the soil water salinity of each depth under the dripper，the greater the soil water salinity of the middle of the two drippers，and the greater the accumulated discharge water and salt at the bottom of the model (p<0.05). The effect of plow pan on the vertical advance distance of wet front was first restrained and then promoted，while the horizontal direction was always promoted. At the end of irrigation，the average value of soil water salinity increased in tillage layer and decreased in subsoil layer with the increase of plow pan bulk density. After 48 hours’ redistribution，the relative soil saturation of cultivate layer and plow pan became greater with the increase of unit weight of plow pan (p<0.05)； and the coefficient of variation of soil water salinity was lower than that at the end of irrigation， but the larger the unit weight of plow pan， the smaller the reduction. The results can provide reference for soil water and salinity and irrigation and drainage management in the field.

The corn variety Jixiang 1 was used as the test material in this study. Through the barrel planting experiment， at the corn seedling stage (M) and jointing stage (B)， the drought stress and re-watering treatment were carried out with different drought stress degrees， including mild drought stress W1， moderate drought stress W2 and severe drought stress W3， and different durations， including 5 days T1， 10 days T2 and 15 days T3， to explore the change rule of biochemical indexes and the response mechanism of summer maize protective enzyme system in the process of drought and re-watering， and then to explore the response mechanism of summer maize to drought and re-watering. The responses of five biochemical indexes (MDA， SOD， POD， CAT and GSH) in summer maize growth stages were compared and analyzed. The results showed that the peak values (activity and content) of each index at jointing stage were higher than those at seedling stage， and the peak values (activity and content) of each index in moderate stress group were higher than those in other treatment groups under stress duration of 10 days. Therefore， the drought resistance of summer maize seedling stage is not strong， so it is not suitable to carry out the irrigation scheme of deficit water with longer duration or more severe drought degree. At jointing stage， it is suitable to adopt the stress treatment scheme with the irrigation amount of 55%~65% soil field capacity for 10 days.

Regulated deficit irrigation is a water-saving irrigation method with wide application prospect in Xinjiang cotton production. However， its water-saving effect under climate change has yet to be evaluated. In this study，representative stations were selected in the early-maturity and early-middle-maturity cotton planting areas in Xinjiang， and full irrigation and regulated deficit irrigation tests were set by using Crop Growth (CROPGRO) -cotton model and future climate data generated by three general circulation models. Cotton production in Xinjiang during 1999-2018， 2041-2060 and 2081-2100 was simulated， and the water saving effect of regulated deficit irrigation was evaluated with the simulation results under the condition that the seed cotton yield in Xinjiang was not significantly affected. The results showed that regulated deficit irrigation could effectively improve cotton water productivity and save irrigation water consumption in Xinjiang， and the optimal strategy of regulated deficit irrigation could save 5%~28% irrigation amount compared with full irrigation. In order to minimize the water consumption of cotton production in Xinjiang without significantly reducing the seed cotton yield， it is necessary to continuously optimize the regulated deficit irrigation strategy to adapt to climate change. The research results can provide scientific reference for cotton sustainable production in Xinjiang.

The study of the influence of the confidence interval of hydrological model parameters on runoff simulation is of great significance to the application of SWAT model calibration. Taking the Jushui River Basin in Macheng City as the research area， the measured monthly runoff data from 1953 to 2006 is selected for analysis and calculation (1995-1996 is the warm period， 1997-2000 is the rate period， and 2001-2004 is the verification period). First， the SUFI-2 algorithm is used to identify the confidence intervals of sensitive parameters， and then the runoff results of the three optimization algorithms (GLUE， PSO， Parasol) before and after the influence of the parameter confidence intervals are considered， and their applicability is analyzed. The results show that only the SUFI-2 algorithm in the first simulation meets the simulation accuracy requirements. Still， the simulation accuracy is not very high， and the GLUE， PSO， and Parasol do not meet the accuracy requirements. The accuracy of the second simulation model is much improved after the optimal confidence interval of the parameters is adopted， and GLUE， Parasol algorithms all satisfy R ²>0.7 and NSE>0.7， which indicating that the model simulation effect is better at this time， and it is more suitable for this study area than the SUFI-2 algorithm. Therefore， before selecting the appropriate method of optimizing parameters， the SUFI-2 method can be used to obtain the confidence interval of the appropriate parameters. On this basis， further parameter calibration can be performed to improve the accuracy of parameter calibration.

In order to reveal the influence of farming methods on the soil properties of sugarcane planting land and the response degree of soil moisture to rainfall， the soil water content under sugarcane coverage in 0~10， 10~30 and 30~50 cm layer under smash-ridging cultivation and no-tillage treatments and precipitation were automatically monitored in situ in the Karst area of Guangxi. In addition， the basic physical and chemical properties of the soil were measured. The results showed that： ① Smash-ridging cultivation increased the total soil porosity and reduced the soil bulk density. The soil organic matter content was increased by 35.4%， 69.7%， and 46.2%， respectively， in 0~10， 10~30， and 30~50 cm layer with significant differences at P<0.05 under smash-ridging cultivation treatment. ②The response degree of soil moisture to rainfall in the two treatments both showed a trend of decreasing with the increase of soil depth. In the event of moderate rain， the soil moisture under no-tillage had an obvious response to rainfall only at 0~10 cm layer. Under heavy rain and torrential rainfall， the response time of the no-tillage treatment to rainfall was 9 h and 3 h， respectively， later than that of the smash-ridging cultivation treatment in the 10~30 cm soil layer， while that in the 30~50 cm layer was 2 h and 5 h， respectively. The soil water content of smash-ridging cultivation showed obvious synchronization and response process to rainfall.③On the whole， the variation coefficient of soil water content increased first and then decreased with soil depth. Before the occurrence of moderate rain， heavy rain and torrential rain， the average soil water content of 30~50 cm layer under smash-ridging cultivation was smaller than that under no-tillage， but the soil water content and variation coefficient of 30~50 cm layer after the occurrence of rainfall were greater than that under no-tillage， indicating that the deep soil water under smash-ridging cultivation could be timely and effectively supplemented after such rain events. In summary， smash-ridging cultivation improves the soil environment， and significantly increases the water content of surface soil and the response degree of soil moisture at each level to rainfall， so that soil moisture can be quickly and effectively supplemented when rainfall occurs.

In order to reveal the water and nitrogen (N) management mode which can improve water use efficiency and carbon fixation capacity of sweet waxy corn， a pot experiment was conducted to study the effects of different drip irrigation and N application modes on dry mass， yield， water use efficiency (WUE)， carbon content and carbon fixation of sweet waxy corn. The results showed that： ① under alternate drip irrigation， the WUE based on dry mass (WUE_s ) and the WUE based on grain yield (WUE_t ) were the highest under medium N level (0.15 g kg^-1 soil). ②compared with conventional drip irrigation from seedling stage to flowering stage (CC)， the water consumption of maize under alternate drip irrigation from seedling stage to flowering stage (AA) by 19.7-20.8%. Under the medium N level， AA mode increased WUE_s and WUE_t by 33.8% and 35.8% compared to CC mode， respectively. ③Under the medium N level， compared with CC mode， AA mode increased carbon fixation of shoots， grains and plants by 16.5%， 16.5% and 16.3%， respectively. ④ Under the same drip irrigation mode， the carbon content and fixation of corn plants were the highest under medium N level. Thus AA mode had the highest water use efficiency and carbon fixation capacity of sweet waxy corn under the medium N level， which was the suitable water and nitrogen management mode for sweet waxy corn.

In order to study the suitable growth conditions of young apple trees， the five-year-old Jinfu No.1 with Malus illinoensis as base stock and SH6 as intermediate stock in Shanxi Fruit Research Institute was used as test material. Four soil moisture limits were set in drip irrigation treatment， namely 80% θ_c （W1），70% θ_c （W2），60% θ_c （W3），50% θ_c （W4）， and the lower limit of irrigation for control treatment (CK， surface irrigation) was 60% θ_c (θ_c was field water holding rate)， the upper limit of irrigation was field capacity. By analyzing the monthly variation of physiological indexes of young apple trees， it was found that the stomatal conductance， photosynthetic rate and transpiration rate of leaves in all treatments had the same monthly variation trend， which increased first and then decreased. The monthly variation trend of leaf water potential was significantly decreased， gradually increased and then slightly decreased， while the monthly variation trend of leaf water use efficiency was firstly decreased and then increased. The difference analysis showed that under drip irrigation， there were significant differences in stomatal conductance， leaf water potential and transpiration rate between W1 and W4， and significant differences in photosynthetic rate between W3 and W4， while there was no significant difference in leaf water use efficiency between different treatments. At the same lower limit of irrigation， the photosynthetic rate of leaves of W3 and CK was significantly different. Based on the comprehensive analysis of TOPSIS， this study determined the planting schedule of each experiment， among which W3 had the largest planting schedule， that is， when the lower limit of drip irrigation water was 60% of the field capacity， it was the most suitable for the growth and development of apple saplings.

In order to study the water situation of different scale irrigation area in Heilongjiang province， to achieve the optimal allocation of irrigation water management and water resource， 80 typical sample irrigation districts with different scales in Heilongjiang Province were selected to calculate the GINI coefficient， and the matching degree of irrigation water consumption and irrigation area in irrigation districts with different scales and water sources was obtained. The Principal Component Analysis method was used to analyze the influencing factors of irrigation water consumption in irrigation districts. The results showed that the matching degree of irrigation water consumption and irrigation area in each scale irrigation area was better in gravity diversion irrigation districts than in pumping irrigation district， while the matching degree of pure well irrigation area was poor. The matching degree between irrigation water consumption and irrigated area was affected by both human and natural factors. Management factors and engineering factors had a positive effect on matching degree， while the natural factors had a negative effect on matching degree.

In order to stimulate the power of the masses to save water， form a water-saving society for the whole people and promote the high-quality development of the Yellow River basin， it is imperative to carry out the research on the green credit system of water-saving agriculture in the Yellow River basin. In this study， the agricultural water-saving technology was used to save water， the conversion relationship between water-saving amount and ecological green coin was established by calculating the amount of water saving in agriculture， and the system and operation mechanism of the green credit system were initially designed to study the green credit system of water-saving agriculture in the Yellow River basin. During the non-critical period of water demand of crops， a certain degree of regulated deficit irrigation can get ecological green coins， and the ecological green coins can be exchanged for "green alliance" products such as native eggs and green plants， and even the "green currency loan". This can mobilize the enthusiasm of the public to save water. The establishment of agricultural water-saving green credit system cannot be separated from the efforts of government institutions， financial institutions， third-party institutions， farmers and other parties. The study of the green credit system can provide scientific and technological support for water resources management and water conservancy reform.

The classification of quasi-protected areas is an important basis and measure for water source pollution prevention and control. The former researchers divided the quasi-protected areas into three types through theoretical research on pumping wells near rivers. Based on the characteristics of multiple water systems and water sources in Tailai Basin， the groundwater flow field was obtained by numerical method， and the quasi-protection area of water sources was divided by MODPATH. According to the calculation results， the quasi-protection zone of water source area in Tailai Basin was divided into three parts， and the relationship between the area of quasi-protection zone and the amount of exploitation， the depth of exploitation， and the distance between water source area and river was analyzed. It provided practical support for previous theoretical research， and increased the quasi-protection area of riverside headland to five categories. By analyzing the flow line near the water source area， the source area of mined water was obtained and classified， and the characteristics of the types of quasi-protected areas with the change of mining amount were analyzed. Based on the position relationship between the quasi-protected area and the river， the influence of the nearby river and the groundwater on the other side of the river on the water quality of the water source area was obtained， which provided a scientific basis for the monitoring and planning of the water source area.

In order to explore the appropriate quota irrigation control index for summer maize， through the combination of low irrigation limits (suitable water CK1； light drought LD； Medium drought MD； Severe drought CK2) and irrigation quotas (30， 45， 60， 75， 90 mm)， the effects of quota irrigation on water consumption characteristics and yield of summer maize under regulated deficit mode were studied. The results showed that there was a significant quadratic function relationship between yield and water consumption. Under the same irrigation quota， the total water consumption of light drought treatment was larger in general. The LD60 and LD75 treatments had better panicle characters and higher grain yield， with little inter-annual variation. The WUE values of LD60 and LD90 treatments were higher， but there was a certain inter-annual difference， which was mainly related to the change of water consumption. In conclusion， the low-quota supplementary irrigation quota of summer maize should not be less than 60 mm. After jointing， 60 mm irrigation can meet the demand when subjected to mild water stress， and the irrigation amount can be appropriately increased when subjected to moderate or above drought， which is more conducive to drought resistance and stable yield of summer maize.

China is short of water resources， and there are many conflicts between regions due to the unreasonable distribution of water rights. In order to solve this problem， this paper applied harmony theory to guide the distribution of water right， and put forward a water right allocation method based on harmony objective optimization. Firstly， the principle of harmonious allocation was determined， and then the evaluation index system of building harmonious regional water rights was constructed. The AHP method was applied for the initial allocation of regional initial water rights， and the harmony equation was used to evaluate the harmony of regional initial water rights. Finally， the optimization model was established to maximize the regional harmony degree， and the optimal allocation of initial water rights was realized by using the Matlab fmincon function. Taking the water right distribution in Zhengzhou as an example， this paper drew the following conclusions：①the comparative analysis results of the schemes before and after optimization showed that the harmony degree of the scheme after optimization was higher than that before optimization， and it was more in line with the planning needs of each region.②The allocation scheme based on harmony objective optimization had good operability and compatibility. The research results can provide some technical support for regional water rights allocation.

In this study， the spatial-temporal differentiation characteristics and influencing factors of agricultural water use efficiency were studied to provide scientific basis for promoting water saving and improving water use efficiency in regional agricultural production. Based on panel data of 11 cities in Hebei Province from 2010 to 2017， the DEA-BCC， Malmquist productivity index and Tobit model were used to investigate the static and dynamic spatial-temporal differentiation characteristics and overall influencing factors of agricultural water use efficiency. The results show that： The overall average level of agricultural water use efficiency in Hebei Province from 2010 to 2017 was relatively low， which presented the characteristics of time change of "inverted V-shaped" and the spatial distribution characteristics of "high in north and low in south". The total factor productivity growth rate of the whole province was 7.2%， which showed a trend of first increasing and then decreasing in time series， and a trend of high in the north and northwest， and low in the east and southwest in space distribution.The agricultural economy level， water-saving agriculture level and crop planting structure， the proportion of animal husbandry and fishery in the total agricultural output value played a positive role in promoting the efficiency of agricultural water resource utilization， however， the endowment of water resources， the degree of mechanization， the ratio of the planting area of food and vegetables in the water resources structure showed a negative hindrance. Especially， the planting structure of crops and the structure of water resources played a major guiding role. There are obvious differences in the utilization efficiency of agricultural water resources in various cities of Hebei Province. The overall level is low， so there is a big promotion space. The key to improve agricultural water resource utilization efficiency is to make full use of technical advantages and water-saving agricultural facilities.

In order to determine whether the historical variation trend of reference crop evapotranspiration (ET ₀) in Northeast China was affected by agricultural development and to provide support for the efficient utilization of agricultural water resources， daily meteorological data of 109 meteorological stations in Northeast China from 1961 to 2017 were used to calculate the reference crop evapotranspiration. The change trends of ET ₀， as well as its radiation and aerodynamic components (ET _rad and ET _aero) of the whole year， the growth season (May to September) and the non-growth season (October to April) were calculated. The proportion of cultivated land area (CF) within a radius of 5 km around the meteorological station was used as an indicator to measure the impact of agricultural activities. The correlation between the variation trend value of ET ₀ and its radiation item (ET _rad) and aerodynamics item (ET _aero) and the proportion of cultivated land area was analyzed， and the change of ET ₀ in different types of sites was compared. The results showed that there was a significant negative correlation between the ET ₀ variation trend observed by meteorological stations in Northeast China from 1961 to 2017 and the CF value of cultivated land area ratio within a radius of 5 km around the stations. The larger the CF value was， the more significant the decreasing trend of ET ₀ will be. ET _rad showed an overall increasing trend and was not correlated with the CF value of the site. The significant decrease in ET ₀ was mainly attributed to ET _aero.The correlation between the trend value of ET ₀ and ET _aero and CF value was more significant in the crop growing season. Compared to the 18 stations with CF<15%， the 33 stations with CF>60% were characterized with mores significant decreasing in ET ₀ and ET _aero， especially in the growth season. Their differences were consistent with the agricultural development in Northeast China. The more significant decreasing in ET ₀ in the agricultural regions over Northeast China can be attributed to the agricultural development and thus should be considered in agricultural water management.

The purpose of this study is to balance the cost and benefit among the government， farmers and water management company， so as to provide reference for the determination of agricultural water price and the evaluation of comprehensive benefit in irrigation district. Based on the analysis of the main cost and benefit of agricultural water use in irrigation district， the cost was reasonably allocated according to the principles of fairness and balance. According to the respective benefits， the quantitative derivation of government investment， irrigation cost and real benefit of farmers was carried out from the perspective of multi-dimensional balance， and the formula of water price calculation and constraint conditions were obtained. Taking Yehe Irrigation district as an example， this paper calculated the income of water-saving investment and the price of irrigation water for different crops by classification， and verified the theory and calculation method of balanced water price by using the theoretical water quantity with the frequency of 70%， which was consistent with the regional precipitation cycle. The example proves that this theory objectively reflects the actual agricultural water supply in the irrigation district， and the determination of agricultural water price according to this theory is helpful to stabilize the grain production in the irrigation district， control the water manage cost， enhance the awareness of water-saving of farmers， and promote the realization of the balance of income and expenditure in the irrigation district.

The existing ozone mixing pump is made by adding an ozone inlet pipe at the suction passage of the ordinary vortex pump with open impeller. It makes use of the gas-liquid mixing characteristics of the vortex pump with open impeller and repeatedly forced vortex to realize gas-liquid mixing. The main problems are short contact time between ozone and water， small contact area， low mixing efficiency， low utilization rate of ozone， low concentration of ozone water and high production cost of ozone water， which make it difficult to popularize ozone water irrigation sterilization technology. In order to solve the key problem of high production cost of ozone water in ozone water irrigation and irrigation sterilization， a honeycomb spiral static mixer was made by making some spherical pits (honeycomb) on the front and back surfaces of the blades of the positive and negative spiral static mixer， and then the positive and negative spiral blades were successively placed in the outlet channel of the vortex pump with open impeller. By making use of the better gas-liquid mixing characteristics of the vortex pump with open impeller， the forced mixing of ozone and water is realized， and the utilization rate of ozone is improved. Then by using the honeycomb placed in the positive and negative spiral blades in the outlet channel of the vortex pump with open impeller to create micro vortex， the ozone is mixed with the water again. So the mixing efficiency of ozone and water is further improved， the concentration of ozone water is again increased， and the production cost of ozone water is further reduced， which will lay a solid technical foundation for the promotion and application of ozone water in agriculture， plant protection， environmental protection and water treatment industries. In order to further improve the mixing efficiency of ozone and water， increase the concentration of ozone water again， and further reduce the production cost of ozone water， it will lay a solid technical foundation for the popularization and application of ozone water in agriculture， plant protection， environmental protection， water treatment and other industries.