Abstract: In order to find out the reasonable amount of water and nitrogen application in the growth period of cotton under mulch drip irrigation in North Xinjiang, two factors, irrigation quantity and nitrogen application rate, were designed through field plot. The irrigation water quantity was set at four levels, those are, W1:5250 m3/hm2, W2:4500 m3/hm2, W3:3750 m3/hm2 and W4:3000 m3/hm2; three levels of nitrogen application (N1:300 kg/hm2, N2:262.5 kg/hm2 and N3:225 kg/hm2) were used to study the effects of different water and nitrogen levels on cotton plant height, stem diameter and LAI, during the growth period of drip irrigation under mulch. Effects of dry matter accumulation and yield on shoot. The results showed that irrigation amount had significant effects on cotton growth. Cotton plant height, stem diameter, LAI and shoot dry matter quality increased with the increase of irrigation amount. The effect of irrigation quantity on LAI and shoot dry matter quality of cotton was greater than that of nitrogen application. When the irrigation quantity was 3750 m3/hm2 and the nitrogen application rate was 262.5 kg/hm2, the boll number per plant, the weight per boll and the yield of cotton reached the highest level. The irrigation quantity and nitrogen application rate were the optimum water and nitrogen rates in the growth period of cotton under mulch drip irrigation in North Xinjiang.

In order to explore the effects of water deficit at different growth stages of low－pressure drip irrigation on citrus fruit growth，yield and water use efficiency，from 2017 to 2018，8 － years － old Shiranui citrus were selected as study materials，a total of 4 water deficit treatments were designed in 4 growing stage of citrus fruit，including leafing－flowering stage ( Ⅰ) ，young fruit stage ( Ⅱ) ，fruit expansion stage ( Ⅲ) and fruit maturing stage ( Ⅳ) ． Meanwhile，the treatment without water deficit was considered as the control with 100% irrigation amount． The 4 water deficit treatments included 85% of irrigation amount ( slight water deficit，LD) ，70% of irrigation amount ( moderate water deficit，MD1) ，55% of irrigation amount ( mild water deficit，MD2) ，and 40% of irrigation amount ( severe water deficit，SD) ． The results showed that the yields of Ⅰ－MD2，Ⅰ－MD 1 and Ⅰ－LD treatments increased by 3．0%，5．1% and 3．1% respectively，and the water use efficiency increased by 4．4%，5．5% and 2．8% compared with CK treatments; the yield and water use efficiency of Ⅱ－LD treatment were increased by 0．9% and 2．8% respectively compared with CK treatment; the yield of Ⅱ－MD1 treatment was decreased by 0．7% and the water use efficiency was increased by 3．5% compared with CK treatment; the water use efficiency of Ⅲ－LD treatment was increased by 5．0% on the premise that the yield of LD treatment was 3．8% lower than that of CK treatment; the yields of Ⅳ－MD2，Ⅳ－MD1 and Ⅳ－LD treatments had no significant difference compared with CK treatments，but the water use efficiency was increased by 9． 2%，6． 3% and 4． 1% respectively． Therefore，stage Ⅰ MD1 treatment，stage Ⅱ and Ⅲ LD treatment and stage Ⅳ MD2 treatment are the optimal irrigation patterns for Citrus under low pressure drip irrigation．

In order to solve the problem of non－uniform irrigation caused by improper selection of sprinklers for gardens irrigation，this study proposed working parameters of four typical pop－up rotational sprinklers for gardens irrigation，including Ｒain Bird－3500，Hunter－PGP， Toro－mini－8 and K Ｒain－PＲO，by comparing their hydraulic performance and economic parameters． The results showed that the flow rate， running speed，combined average sprinkler intensity and sprinkler uniformity coefficient of the four garden pop－up rotational sprinklers are basically the same; with the increase of the working pressure，the flow rate of the sprinklers increased; with the increase of the sprinkler spacing，the average application rate，the combined sprinkler uniformity and investment of per unit tended to decrease overall． When sprinkler spacing was constant，the higher the pressure was，the greater the sprinkler uniformity was． When considering the irrigation quality， energy conservation and economic analysis，it is recommended that the working pressure of Toro－mini－8，Ｒain bird－3500，K Ｒain－Pro and Hunter－PGP should be at 0．15，0．20，0．20 and 0．25 MPa respectively，the sprinkler spacing of Toro－mini－8 should be 12 m×12 m and other sprinklers should be 14 m×14 m．

In order to understand the effect mechanism of straw － return on the growth parameters of winter wheat，the straw mulching treatment was conducted on wheat in the Huang － Huai － Hai plain through field experiment，and its soil physicochemical parameters， morphological characteristics，and photosynthetic performance were observed． The results showed that straw mulching resulted in a significant increase in soil water content，but the N and P contents in the soil were significantly reduced，while the K content in the soil was not significantly affected． Straw mulching can significantly increase the leaf area of winter wheat and make the stomatal spatial distribution more regular，so as to effectively improve the net photosynthetic rate of leaves and finally increase the panicle grain number and 1 000－grain weight of winter wheat．

In order to explore the effect of nitrogen application level on plant growth under micro－moist irrigation，pepper was planted in a greenhouse in a soil box with the same specifications． Two pressure heads of 1．5 m and 2 m were set up in the experiment． Three nitrogen application levels ( 0，500 and 1 000 mg /L urea) were used，namely，500 mg /L under 1．5 m pressure head ( treatment A) ，1 000 mg /L under 1．5 m pressure head ( treatment B) ，and 1． 5 m pressure head． Six different treatments were applied，namely，0 mg /L nitrogen application level ( C treatment) ，500 mg /L nitrogen application level ( D treatment) under 2 m pressure head，1 000 mg /L nitrogen application level under 2 m pressure head ( E treatment) ，and 0 mg /L nitrogen application level under 2 m pressure head ( F treatment) ． The growth status and yield of pepper plants were analyzed by repeated experiments three times for each treatment． The results showed that the growth status of greenhouse pepper plants under 2 m pressure head was better than that under 1．5m pressure head，and the growth status of pepper plants under 500 mg /L fertilization under the same pressure head was the best．

The water and heat transfer in seasonal frozen soil with straw mulch thickness of 5, 10, 15, 20 and 30 cm was simulated by using the Simultaneous Heat and Wate (SHAW).The results showed that the model had a good effect on soil moisture simulation, and the root-mean-square error (RMSE) of soil moisture simulation was 0.003-0.08 during the simulation period. Due to surface soil is susceptible to changes in external meteorological conditions, the model had a relatively large deviation of soil temperature simulation but within a reasonable range. The calibrated SHAW model was used to simulate and predict soil water and heat transport under straw mulch with thickness more than 30 cm. The simulation results showed that the water and heat transport is almost unaffected by the external climate change under straw mulch with thickness more than 45 cm.

In order to reveal the soil water distribution characteristics under root irrigation, the mathematical model of soil water movement under root irrigation was established according to the characteristics of soil water movement in root zone.The model experiment of soil water movement in root-zone irrigation was carried out in laboratory, and the simulated and measured values of soil water in root-zone irrigation were compared and analyzed.The results show that the average absolute error, relative error and root mean square error of the model are 0.01 cm3/cm3, 4.96% and 0.013 cm3/cm3, respectively.This shows that the model has high simulation accuracy and can be used to simulate soil moisture distribution in root irrigation.The model was used to simulate and analyze the effects of the length and diameter of different irrigators on the distribution characteristics of soil moisture under root irrigation.The results show that the longer the length of the emitter, the deeper the soil moisture distribution in the vertical direction, the closer the horizontal radial distribution, the larger the diameter of the emitter, the shallower the soil moisture distribution in the vertical direction, and the farther the radial distribution in the horizontal.The research results can provide a basis for the rational determination of the technical parameters of Root-zone irrigation.

It is an indisputable fact that the global climate is getting warmer，and the greenhouse gas emitted from farmland soil made a great contribution to it，at the same time，soil salinization has become a major bottle neck restricting the development of the current farmland． In order to alleviate salinization of farmland soil，simultaneously alleviate greenhouse gas emission of farmland and develop sustainable low－ carbon agriculture，and promote comprehensive utilization of waste resources，this paper selects the biochar，gypsum，gypsum with organic fertilizer as soil amendment，the static dark box－gas chromatography method was used to collect the soil greenhouse gases ( CO2，CH4， N2O) in the salinized farmland in situ sampling，and the effects of different treatments on the law of greenhouse gas in the soil were analyzed in order to provide a theoretical basis for suppressing and reducing greenhouse gas emissions in agriculture． In this study，4 experimental treatments were set up，namely，biochar ( DC) ，gypsum ( DS) ，gypsum with organic fertilizer ( DSF) and blank ( CK) ，and 3 replicates were set for each treatment，and the same irrigation and fertilization measures were supplemented． The results showed that the average CO2 emission fluxes of each treatment were significantly different ( p＜0．05) ，and gypsum had the best effect on inhibiting CH4 and N2O emission fluxes; the greenhouse gas emission intensity ( GHGI) treated by DC，DSF and CK was not significantly different，but significantly different from that of DS; compared with the control group，the greenhouse gas emission intensity ( GHGI) of DSF，DC and DS treatment showed a decreasing trend，reducing by 5．57%，16．77% and 34．93%，respectively; applying biochar and gypsum had obvious effect on reducing pH

and EC of salinized soil; the organic matter，alkali－hydrolyzed nitrogen and available phosphorus in salinized cropland could be increased by biochar and gypsum; comprehensive analysis of the effects of various treatments on greenhouse gas indicators showed that gypsum had the best effect on curbing greenhouse gas emissions，followed by biochar; Biochar had better effect on soil improvement．

In order to explore the relationship between crop yield and water salt stress, field experiments were conducted under deficit irrigation with saline water in Shiyang Rive Basin. It introduced into the crop-water-salt production function. The crop-water-salt production function parameters were calculated, calibrated and validated based on the field experiments measured data. The results showed that the simulated evapotranspiration and yield agreed well with the measured values of seed maize at different growth stages. The RMSE values were all lower than 10 mm and the MRE values were lower than 25% within the allowable error range in seed maize evapotranspiration calibration and validation. The RMSE values were all lower than 800 kg?hm-2 and the MRE values were lower than 15% within the allowable error range in seed maize yield calibration and validation. The crop-water-salt production function parameters after calibration and validation were b=6.72，ky1=0.43，ky2=0.82，ky3=1.41，ky4=0.65，ky5=0.24，respectively. The yield influencing factors (ky) reflected sensitivity to the seed maize at different growth stages under water salt stress. The crop-water-salt production function can well simulate the seed maize evapotranspiration and yield under water salt stress after calibration and validation. It provides scientific basic for making deficit irrigation with saline water schedule for seed maize in study area.

In order to establish a reasonable drip irrigation schedule for corn，field experiments were conducted to study the effects of different buried depths of drip irrigation zones and different drip flow rates on the growth of corn． The results show that the plant height of D1 ( the buried depth is 25 cm) is higher than that of D2( the buried depth is 35 cm) by 15% to 30% in seedling stage and jointing stage，while after tasseling stage，the plant height D1 is slightly higher than that of D2，but there is no significant difference between all the treatments ( p ＜0．05) ; the plant height of Q2( the dripper discharge is 1．38 L/h) is higher than that of Q1( the dripper discharge is 1．05 L/h) and followed by that of Q3( the dripper discharge is 1．90 L/h) in the same depth，and the wetting body in Q2 is the most suitable for maize growth; the leaf area index of D2 is lower than that of D1 by 4% to 15%; the effect of buried depth on leaf growth is greater than that of dripper discharge; the water consumption of D1 treatment is 21．9 mm higher than that of D2 treatment，and the minimum water consumption of Q2 treatment is 366．19 mm; the drip flow has little influence on the water consumption of maize; the D1Q2 treatment has the highest yield and the highest WUE． It is recommended that the drip flow of corn in Tongliao should be 1．38 L/h and the buried depth should be 25 cm，the irrigation schedule should be 7 times for the whole growth period with an irrigation quota of 175 mm．

In order to explore the effects of reducing irrigation water in different periods of tomato root vigor and water use efficiency, in this experiment, tomato 1702 was used as the test material and four treatments were set: sufficient water to the 90% field moisture capacity in the whole stages(W1), seedling stage decreased by 50% of irrigation water (W2), seedling and flowering period continuous reduce 50% irrigation water (W3) and a 50% reduction in the whole stages(W4), tomatoes were measured the soil moisture content of different depth in the whole stages , root vigor and yield. The results showed that: Treatment of W2 in whole growth period accounted for 63%-81% of total field holding basically maintained higher water content in all layers of soil during the whole growth period, and the water supply was sufficient to meet the requirements of tomato water demand. With the advancement of growth stage, W2 treatment can delay the aging of tomato root system, especially the lower root system, and the longer it takes to restore irrigation, the more obvious the effect. The yield difference between W2 and W1 was not significant. W2 treatment has the highest water use efficiency, without significant yield reduction, the irrigation water was saved by 18% compared with W1 treatment.Reducing irrigation water in different stages had significant effects on soil moisture content, root activity and yield of tomato. Reducing irrigation water by 50% at seedling stage and rewatering at flowering and fruit-setting stage (W2) could provide reference for greenhouse tomato planting in semi-arid regions of China.

In order to fully understand the current situation and changing trend of water resources utilization in Shanxi Province． Based on the water footprint theory，this paper analyzes the situation of water resources utilization in Shanxi Province and its administrative regions from 2007 to 2016，discusses the spatial － temporal variation characteristics of water resources allocation and utilization，and evaluates the coordinated development of water resources utilization and economic growth in Shanxi Province based on the decoupling evaluation model of coordinated development． The results show that: ① the water footprint of Shanxi Province is on the rise in recent ten years，and there are significant differences among different administrative regions． Among them，the water footprint of Yuncheng city is the highest，while that of Yangquan city is the lowest． The average annual per capita water footprint is 731．22 m3 /person． ② the water footprint structure was basically stable within the time limit of the study，the proportion of agricultural water footprint remained at about 90%，the industrial water use declined slightly，and the domestic and ecological water use increased slightly． ③ the water resource self－sufficiency rate of Shanxi Province is very high，with an average of 98．97%． Except Taiyuan，the water resources self－sufficiency rate in other areas are kept above 97%． ④ the economic benefit of water footprint in Shanxi Province increased from 28．13 yuan /m3 in 2007 to 43．23 yuan /m3 in 2016，and the economic benefit of water footprint in each administrative region increased to different degrees in 10 years． ⑤ in the past 10 years，the water resource pressure index of each administrative region of Shanxi Province was greater than 1，and the overall water resource pressure index rose from 1．96 in 2007 to 2．24 in 2016，indicating that the water resource utilization of Shanxi Province was in a state of long－term insecurity with obvious regional differences． ⑥ the relationship between economic growth and water resource utilization in Shanxi Province is coordinated except in 2013 and 2014．

In order to deeply understand the water resources carrying capacity level of the Central Plains Urban Agglomeration in Henan Province, the paper improved the existing evaluation index classification is not specific enough and the result of index weighting is not reasonable enough, constructed the suitable water resources carrying capacity evaluation index system, used the comprehensive weighting method combining analytic hierarchy process (AHP) and entropy weight method to weigh the evaluation indexes, and constructed a fuzzy comprehensive evaluation model to comprehensively evaluate and analyze the water resources carrying capacity level of the Central Plains Urban Agglomeration in Henan Province in 2015. The results show that the water resources carrying capacity of the Central Plains Urban Agglomeration in Henan Province is generally good in 2015, and all 10 cities are in a carrying state. From the point of view of each subsystem, the overall situation of water resources subsystem is the worst, the scores of evaluation indexes are generally low, and the overall situation of social subsystem, economic subsystem and ecological subsystem is good, among which the economic subsystem contributes the most to the water resources carrying capacity of the Central Plains Urban Agglomeration in Henan Province. In the future, the Central Plains Urban Agglomeration in Henan Province should reasonably control population, deepen industrial restructuring, and rationally plan the development and utilization of water resources.

In order to explore the coupling degree of water demand and precipitation of drought－grown maize，millet and potato in loess hilly area of northern Shaanxi province，the characteristics of water demand，climate drought and coupling of water demand and precipitation of three crops during the growth period ( May to September) were analyzed based on the daily meteorological data of Suide county from 2000 to 2014． The results showed that: the water demand of maize，millet and potato in the whole growth period was higher than rainfall in the same period，and the water demand of millet in the whole growth period was significantly lower than that of maize and potato by 168．75 and 142．44 mm，respectively ( p＜0．05) ; the water demand of the three crops was the largest in June，accounting for 30．12%，40．13% and 27．46% of the water demand of the whole growth period，respectively; drought occurred most frequently in June，reaching 28．57%; the coupling degree of water demand and rainfall of three crops showed a good three－order polynomial relationship with time ( Ｒ2 ＞0．80) ，which were the smallest in June ( 0．14～ 0．16) ; the coupling degree between water demand of millet and rainfall was significantly higher than that of maize and potato in July，August and September ( p＜0．05) ; drought will continue in May and September，and will weaken from June to August． The coupling degree of water demand and precipitation of three crops will continue to keep the same trend in May and June，but will increase from July to August． It is suggested to increase the planting area of green organic millet with high added value，reduce the planting area of corn and potato，and adopt the combination technology of rain－collecting irrigation and furrow mulching to make full use of precipitation resources．

In view of the characteristic that the traditional water resource carrying capacity evaluation is only based on the evaluation index data，the evaluation index system is constructed firstly，and then the combination weight is obtained by combining the objective weight and subjective weight obtained by the standard deviation contribution rate method and the relative entropy aggregation model of group decision－ making． According to the three decision －making ideas，pre －score is introduced and the improved TOPSIS algorithm and pre － score are combined to solve the final score． Based on the rating system of the three decision－making idea，the water resources carrying capacity is divided into three levels: excellent，good and poor，which is not only closer to the actual situation，but also easier for people to better understand the water resources carrying capacity by visually displaying the evaluation results． 

In order to explore and coordinate the relationship between crop production and water consumption in different regions，the water footprint theory and method were used and 17 factors affecting the water footprint of corn production were selected for significant analysis． Based on principal component analysis，three methods including K－means clustering，hierarchical clustering method and fuzzy C－means clustering were used to cluster the water footprint of maize production in Liaoning province． The results showed that among the factors positively correlated with the water footprint of maize production，the fertilizer amount per unit area reached a significant level，and the ratio of blue water footprint to the total water footprint reached an extremely significant level．Among the negatively correlated factors，the ratio of precipitation and plain area to the total area reached a significant level，and the latitude and maize yield per unit area reached an extremely significant level． According to the clustering results，Liaoning were divided into five regions． Including the Ⅰ zone of Green Water Satisfaction－Comprehensive Development Zone ( Anshan，Fushun，Benxi，Dandong) ，the Ⅱ zone of High Production Water Footprint － Protection Development Zone ( Dalian，Yingkou，Huludao) ，the Ⅲ zone of Low Production Water Footprint － Key Development Zone ( Shenyang，Tieling，Panjin) ，the Ⅳ zone of Blue Water Dependence－Optimized Development Zone ( Fuxin，Jinzhou，Chaoyang) and the V zone of Higher Production Water Footprint－Moderate Development Zone ( Liaoyang) ． Different water use strategies and maize production models should be adopted in different regions according to their own characteristics． This study provides reference for spatial distribution of maize production and scientific management of agricultural water resources in Liaoning province．

In order to improve the applicability and accuracy of Prietley-Taylor (P-T) models in Jiangxi Province and the regional crop water requirement estimation accuracy level and optimize the allocation of water resources, based on the 27 meteorological stations in Jiangxi province and neighboring provinces of 16 meteorological stations for 1961-2010 years the daily meteorological data in FAO Penman-Monteith (P-M) model as the standard, P-T model parameters of the annual rate (PT1) and quarter rate (PT2) were studied, and the simulation results of P-T model are analyzed and the accuracy evaluation. The results showed that the constant parameters of the annual rate were between 1.05 and 1.18, and the parameters showed the highest in the northern plain and the low in the western mountain area. The parameters of spring and summer are smaller, and the winter is the largest, with a little overestimated. The two calibration methods of P-T model showed good applicability on annual scale and monthly scale. However, t-test results show that the data of season based fixed mode is more consistent. PT2 has enhanced the responsiveness of P-T model to seasonal variation, and improved its accuracy and adaptability. It can be used for simplified calculation of ET0 under the condition of lack of meteorological data in Jiangxi Province.

The current research on water right allocation has been done most focused on basin or province (city) level but least on the country level and its below. Based on the statistical data in 2015, this paper takes Binyang County, Guangxi Province as an example to calculate the agricultural water rights allocation for each township by using fuzzy optimization model and improved catastrophe model. Furthermore, the rationality of allocation is analyzed by comparing the results of two models with the actual water use at each township in 2016. The results of Bingyang County example shows that both two models can be applied to calculate water rights allocation at country level and the improved catastrophe model has a more accurate result.

In order to quantify the effect of fog irrigation on tea plantation and provide reasonable irrigation suggestions，a monitoring system for tea plantation fog irrigation based on LOＲA communication is designed in this paper． The system collects the soil and air temperature and humidity information of tea garden through the terminal node of environmental collection，and collects the information in the communication control node by using LOＲA communication network． On the one hand，the communication control node temporarily stores the information and backs up the local information，on the other hand，it encapsulates and processes the data，and sends the data to the cloud server by using the 4G network． Users are provided different ways of human－computer interaction． The system continuously monitors the effect of fog irrigation on tea garden for 20 days． The experiment proves that fog irrigation mainly affects the atmospheric temperature and humidity，and can be used to create an atmospheric environment suitable for tea tree growth，while the effect on soil temperature and humidity is small，but it has a good performance in soil and water conservation

In order to consider the weight of subjective factors and objective factors, as well as the horizontal and vertical influence degree of indicators, an evaluation model of water saving irrigation project based on the improved CRITIC-G1 method with mixed cross weight and TOPSIS model is constructed.In this articles, the improved CRITIC method was used to improved the CRITIC information of each evaluation index, the ratio of expert's subjective important degree is revised by the information improved G1 method which is contained in index, and then it is derivated that improved CRITIC-G1 hybrid cross weight, using the improved TOPSIS method to calculate the proximity between the optimal solution and evaluation scheme and sorted, the results show that the evaluation result difference degree is smaller, the composite model is more effective and feasible.Based on the empirical application of the model, it is found that using the improved CRITIC information to modify the importance degree in G1 subjective weight method can not only reflect the subjective judgment of decision makers, but also better reflect the objective information of data, thus making the comprehensive evaluation result more scientific and reasonable.

Farmland evapotranspiration ( ET) is a key parameter for water transport in the soil－crop－atmosphere continuum，which is closely related to crop physiological activities and yield． Accurate and real－time estimation of evapotranspiration in the field is very important for studying crop growth and development． In this paper，canopy temperature of summer corn was inverted based on uav thermal infrared sensor， an ETd，t evapotranspiration model of summer corn was constructed based on the inverted canopy temperature，the accuracy of crop evapotranspiration inversion by the model was verified，and the ETd，t and t related influencing factors were analyzed． The results showed that: for the ETd，t calculated by the crop evapotranspiration model of thermal infrared canopy temperature，the lowest value of t appearedat seedling stage，which was 3．42 mm/d; and the highest value was 10．94 mm/d at the grouting stage． The measured value ETd，e related to vorticity and the calculated value ETd，f of FAO penman－monteith model were used to verify． At the level of P lower than 0．01，there was a significant linear relationship ( Ｒ2 = 0．739，0．742，ＲMSE= 0．676，0．109 mm/d ) ，the estimated accuracy of ETd，t reached over 80%． The calculation of ETd，t was influenced by daily net radiation，wind speed，temperature，rainfall and other meteorological factors，ETd，t were different for different meteorological conditions． Leaf area index ( LAI) was the most important biological factor in summer corn farmland，and it was linearly positively correlated with ETd，t ( Ｒ2 = 0．700) ． Aerodynamic impedance ( ra ) was the most important environmental driving factor，and ra had a negative linear correlation with ETd，t ( Ｒ2 = 0．696) ． With the change of vegetation coverage ( NDVI) ，ETd，t showed the same trend ( Ｒ2 = 0．656) ． Therefore，the canopy temperature calculation ( ETd，t ) based on uav－based thermal infrared inversion can better reflect the evapotranspiration change process of summer corn in the field，thus providing a scientific basis for estimating crop evapotranspiration using uav－based thermal infrared remote sensing