Mulching film brings a series of pollution problems while promoting production increase. Biodegradable mulch can increase production and reduce pollution to some extent. In this study, a comparative experiment between ordinary plastic film, two kinds of full-biodegradable film (transparent film and black film), and bare-field cultivated was conducted to explore and analyze the degradability of biodegradable film and its effects on soil moisture, temperature, and corn growth. The results showed that the degradation rate of the full biodegradable film was significantly faster than that of the ordinary film, and that of the black full biodegradable film was slightly faster than that of the transparent full biodegradable film; the moisture content of each soil layer under different mulch films increased with the increase of depth, and the middle layer water content increased the most; in the early growth stage, there was no significant difference in soil moisture content of the three kinds of mulch films, but in the later stage, the soil moisture content of the transparent full biodegradable film and the black full biodegradable film was more and more close to the bare land and the difference with that of the ordinary film was getting bigger; all the three kinds of mulching films could effectively increase the ground temperature in all stages of corn growth, but the temperature increasing effect weakened with the increase of soil depth, moreover, the temperature increasing effect of the two full biodegradable films was getting weaker in the later growth stage; film mulching could significantly increase the germination rate of corn, speed up the process of corn growth, increase the plant height, stem thickness, leaf area and aboveground dry matter weight of corn, which was conducive to the improvement of economic benefits to a certain extent. Therefore, it is feasible to replace ordinary plastic mulch with full biodegradable mulch.

In this study, under the condition of drip irrigation and fertilization, field experiments were carried out to study the effects of different irrigation amount and nitrogen application amount on the photosynthetic characteristics and yield of potato. Three irrigation rates and three nitrogen levels were designed by two factors and three levels of random block. There were a total of 9 treatments, and each treatment was repeated for 3 times, with a total of 27 experimental plots. The results showed that under the condition that the irrigation volume was 1 800 m3/hm2, the net photosynthetic rate, transpiration rate and stomatal conductance all increased first and then decreased with the increase of nitrogen fertilizer amount. When the sun was full, the time points of the minimum value and maximum value were 14∶00 in the afternoon and 10∶00 in the morning respectively. Under the condition of 900 m3/hm2 irrigation volume, the diurnal variation trends of stomatal conductance, net photosynthetic rate and transpiration rate of potato were basically the same, and the peak value appeared around 10∶00 am and 16∶00 pm. Under the conditions of 900 and 1 350 m3/hm2, the yield generally increased with the increase of nitrogen application. Under the conditions of nitrogen application of 120 kg/hm2 and 180kg/hm2, the yield generally increased with the increase of irrigation water. The yield of different water and nitrogen treatments was higher than that of CK (No irrigation, no nitrogen) by 9%~43%. It can be concluded that the treatment of T6 (Medium water and high nitrogen) was the most beneficial to the improvement of photosynthetic capacity and yield of potato.

In order to deeply understand the influence of agrometeorological factors on the reference crop evapotranspiration (ET0) in typical maize planting areas under shallow subsurface drip irrigation, in this study, the Extended Fourier Amplitude Sensitivity Test (EFAST) was used to analyze the global sensitivity of agricultural meteorological factors, to identify the meteorological causes of different ET0, so as to provide reference for understanding the impact of agro-meteorological changes on crop evapotranspiration and water consumption and formulating reasonable irrigation schedule. The results showed that: the variation of meteorological factors of Tongliao in the growth season of 2017and 2018 had the typical meteorological characteristics of Xiliao River Basin, that was, the spring was cold, dry and windy, the summer was humid, hot and rainy; the hydrology year type of the two years was the year of abundant precipitation and the year of normal precipitation respectively. ET0 was positively correlated with daily maximum temperature, minimum temperature, daily average wind speed and sunshine hours, and negatively correlated with average daily relative humidity. The first-order and global sensitivity index of meteorological factors to ET0 in this typical area was ranked as follows: daily average wind speed (0.220/0.324) > maximum temperature (0.125/0.157) > daily average relative humidity (0.100/0.139) > sunshine hours (0.091/0.116) ) > minimum temperature (0.007/0.034), and the first four indexes were highly sensitive factors. In the growing seasons of 2017 and 2018, the limits of ET0 were 1.5~9.3, 1.3~9.6 mm/d, respectively, the limits of ET0 for sampling weather value was 0.5~9.2 mm/d. The higher the frequency of high temperature, high wind speed, low humidity and long sunshine in the growing season, the greater the potential evapotranspiration consumption. Under the influence of agrometeorological changes, the irrigation schedule needs to be adjusted accordingly.

In order to formulate the irrigation management parameters and improve the water use efficiency of cucumber planted in autumn-winter in the arid zone of central Ningxia. The field experiment was carried out to study the effects of different irrigation frequencies on the yield and root distribution of grafted cucumber. The results show that, in Greenhouse Autumn-winter Planted Condition, cucumber root mainly distributed in 0-20cm soil layer, irrigation frequency in fruiting period had significant effect on cucumber root growth, but had no significant effect on different soil layer distribution. Reducing irrigation frequency can promote the growth of cucumber roots i, which is beneficial to fruit setting, yield increase and sugar content accumulation in fruit. Under the condition of average daily temperature of 18 ℃ and irrigation quota of 1500 m3/h m2, The optimum irrigation interval of cucumber is 7d .

Sugarcane has been the main source of Guangxi economics and its cultivation area reaches more than 60% of the total area of sugarcane in China. However, the cultivated sugarcane is mostly located on the hillslope, and the heterogeneous soil texture, slope, and nonuniform management lead to the spatial variability of sugarcane yield, so it is difficult to estimate by using crop modeling since it requires too much input data. The information of leaf area index and plant height of sugarcane in different periods can be easily obtained by unmanned aerial vehicle (UAV), and the soil moisture at different depths can be obtained via ground-based sensors. In this paper, the correlation between plant height, leaf area index, soil moisture, and sugarcane yield data collected in 2016 from 60 experimental plots at Chongzuo, Guangxi, was analyzed. It was found that: Crop height data from UAV observations were more helpful than other observations; The leaf area index data collected at the middle stage of elongation and crop height at the end of elongation were the most informative; Root-zone soil moisture at one month after sowing was highly correlated with crop yield. By using the multi - variable linear regression analysis to estimate the sugarcane yield, the correlation index R2 can reach 0.87, which indicated that the multi - variable linear regression analysis is a relatively convenient method to estimate sugarcane yield.

In order to improve the water use efficiency of vertical linear irrigation, a simulation experiments was conducted to study the infiltration rule of different line source diameters of vertical line source irrigation, and the applicability of three conventional infiltration models was compared. The results showed that the infiltration rate and cumulative infiltration volume increased with the increase of the diameter of the line source; all the three models could simulate the infiltration law of different line source diameters, among them, the Kostiakov infiltration formula and Philip infiltration model were more accurate, and the Horton (deformation) infiltration formula was more suitable for the simulation of the middle and late infiltration. And the empirical formulas of three infiltration models with line source diameter were obtained. The research results can provide a theoretical basis and practical reference for rational applications of vertical line source irrigation.

In order to explore the effect of different ratios of phosphorus and potassium fertilizers on apple quality under drip irrigation conditions and the suitable phosphorus and potassium fertilizer application schemes for high quality apples, the quality index of apples with different phosphorus and potassium ratios was determined by field experiment. A total of 5 drip irrigation treatments were set up in the experiment, including low phosphorus medium potassium (P1K2), medium phosphorus medium potassium (P2K2), high phosphorus medium potassium (P3K2), medium phosphorus low potassium (P2K1), medium phosphorus high potassium (P2K3), and ground Irrigation control group CK: medium phosphorus and potassium (P2K2). The results showed that in each treatment, the single fruit weight and soluble solids content of P2K3 treated apples were the largest and the acidity value was the smallest; the fruit shape index and pulp hardness value of P2K2 treated apples were the largest; drip fertigation was more favorable to apple trees than traditional ground irrigation; Fruit growth and development could significantly improve apple fruit weight, fruit shape index, pulp hardness, soluble solids, acidity and other quality indicators. The principal component analysis of quality indicators of each treatment with comprehensive consideration of fertilization amount and economic benefit indicated that under drip irrigation conditions, the ratio of phosphorus to potassium fertilizer of the P2K2 treatment (P2: 70 kg/hm2, K2: 100 kg/hm2) was the most beneficial to improve the fruit quality of apple trees.

The groundwater level of the saline-alkali wetland is high and the salt is difficult to be leached in Shuxin forest farm, Qingtongxia, Ningxia, China. Aiming at this problem, buried ditches with different depths (T1-1.5 m, T2-1.2 m, T3-0.9 m, and T4-0.6 m) and control tests (CK-no ditches) were set in the field. After irrigation, the changes of soil water and salt content in 0~100 cm soil layer were studied on the 5th, 15th and 25th day, and the growth index, yield of sunflower were measured. The results showed that compared with CK, the suitable ditch could increase the drainage rate of saline-alkali wetland, effectively reduce the content of water-soluble salt in the soil, improve the growth environment of crops, and increase crop yield. Compare the relative change rate of soil moisture and salinity in 0~100 cm soil layer of each treatment on the 25th day and the 5th day after irrigation, it showed T2>T1>T3>CK>T4 and T2>T3>T1>T4>CK, respectively. The seed yield of sunflower after treatment was T2>T1>T3>T4>CK. In summary, it could be concluded that when the buried depth of the ditch was 1.2 m, the effect of drainage and salt exclusion was the best, the growth and yield of sunflower was the best.

In this study, field experiments were conducted to study the effects of different fertilization methods and irrigation treatments on the yield and water use efficiency of waxy maize under the conditions of full-film double-ridge furrow sowing in the Jinzhong Basin of Shanxi Province so as to explore the best cultivation mode of waxy corn with high yield and high water use efficiency. In the experiment, three kinds of fertilization methods and two kinds of control irrigation were set up with randomized block design, and the effects of different irrigation and fertilization treatments on waxy corn yield and water use efficiency were studied. The test results showed that: ① under the conditions of full film double furrow planting, both F2 treatment and F0 treatment could provide better soil moisture environment than F1; ② the fresh ear yield of waxy corn showed a change of rapid increase-slow increase-negative increase with the increase of water consumption; ③ the F2I1 treatment had the highest soil water utilization rate and the highest irrigation water utilization rate, which was a good supporting water and fertilizer measure for high yield of waxy corn and efficient utilization of water under the condition of full film double furrow planting.

In order to reveal the effect of biochar application on the production and emission of N2O from paddy fields under water-saving irrigation, the response of N2O concentration profile of paddy soil under water-saving irrigation to biochar application was analyzed based on field experiments and microelectrode technology in this study. The results showed that N2O concentration of paddy soil presented a decrease-increase-decrease trend from surface soil layer to subsoil during most of the periods after fertilization, and it would be different in the early or late stages after fertilization. Medium amount of biochar (20 t/hm2) input decreased N2O concentration in the paddy soil profile under water-saving irrigation after tillering fertilization, but the reverse was observed after panicle fertilization. High amount of biochar (40 t/hm2) input increased the N2O concentration in paddy soil profile during some periods after fertilization. The N2O concentration at different depths in flooding irrigation paddy field was significantly higher than that in controlled irrigated paddy field. The increase of N2O emission in controlled irrigated paddy fields was mainly related to the fact that the anhydrous layer management of water-saving irrigation promotes N2O emissions from the soil. The results can provide scientific basis for a more comprehensive evaluation of the environmental effects of water-saving irrigation paddy fields and the realization of sustainable utilization of water and soil resources in paddy fields.

Different types of drip irrigation tapes with inlay patch as the main material were used to study the response relationship between dripper spacing and dripper discharge and burst pressure at different temperatures, and the uniformity of dripper discharge at normal temperature and pressure. Burst pressure experiments of different types of drip irrigation belt were conducted at the temperature of 15, 23, 30, 37 and 45 ℃. The results showed that there was a negative correlation between the temperature and the burst pressure when the temperature was lower than 37 ℃, while when the temperature was 45 ℃, the burst pressure tended to rise with the increase of temperature; At the same temperature, the larger the dripper spacing and dripper discharge, the greater the burst pressure it will bear. It was found that the flow uniformity indexes of the three types of drip irrigation belts all were qualified.

According the principle of soil negative pressure, product structure optimization design and utilizing advanced technologies such as information perception, wireless transmission, and microelectronic control, we have developed and assembled a new type of irrigation flow regulating valve suitable for water distribution pipes, with the actual soil water condition sensing collection, information feedback and real-time adjustment and control of water flow and other composite functions. According to its working principle and design technical indicators, the index test and performance analysis of the irrigation flow regulating valve were performed through indoor simulation tests. The results show that the opening range of the test DN25 flow regulating valve sample is 0~100%, under 100~300 kPa water supply pressure, the accuracy of flow adjustment is 81% -99%, and the control sensitivity is high. The response time of the valve blade gradually increases with the increase of the valve opening, and the maximum response time for one-way opening and closing is less than 3s. It not only achieve better flow precision allocation effect of water-saving irrigation, but also provides technical basis for further structural optimization, performance improvement, and product shaping of the flow control valve.

In order to clarify the applicability of the calculation model for reference crop evapotranspiration (ET0) in the irrigation district of Tibet Plateau and to recommend the calculation model suitable for meteorological data shortage condition, in this study, based on the long series data of meteorological stations in Manla, Moda and Jiangbei irrigation district, the Penman-Monteith (FAO 56 PM) model recommended by FAO was used as the standard to evaluate the applicability of five commonly used models. The results showed that the variation trends of daily scale ET0 calculated by Makkink, Irmark-Allen, FAO 17 Penman, Hargreaves-Samani and Priestley-Taylor models was all consistent with that of the FAO 56 PM model, and the annual variation pattern of ET0 increased and then decreased, and the peak value appeared from June to July, but the applicability of each model was significantly different. The daily MAE, RMSE, and NSE values of Makkink model were 0.37 mm/d, 0.45 mm/d and 0.84, respectively, with the highest simulation accuracy and reliability. Followed was the Irmark-Allen model with the MAE, RMSE, NSE values of 0.65 mm/d, 0.71 mm/d and 0.62 respectively. The Priestley-Taylor model had the poorest performance, with the MAE value up to 4.91 mm/d and the NSE value less than 0. On the annual scale, the calculation results of each model were overestimated at different degrees, compared with FAO 56 PM model. The NSE values of FAO 17 Penman, Hargreaves-Samani, and Priestley-Taylor models were between -3 571.76 and -118.00, and the simulation results were not credible. The NSE value of Makkink model was the closest to 0, the simulation result was credible, but the error in the simulation process was large. Based on the comprehensive evaluation, the Makkink model was recommended as a simplified model of ET0 under the meteorological data shortage condition in the irrigation district of Tibetan Plateau.

In order to explore the water-saving and high-yield irrigation quota of spring wheat under micro-spray belt irrigation in Hexi corridor, in this study, the “Yongliang No.4” was used as the experimental material. In the late growth stage (booting to maturity), five irrigation times were set, and four irrigation quotas were set at 30 mm (W30), 40 mm (W40), 50 mm (W50), and 60 mm (W60) to study the effects of different irrigation amounts on growth, yield and WUE of Hexi spring wheat under micro-spray belt irrigation in the late growth stage. The results showed that: the plant height of spring wheat increased with the increase of irrigation water in the late period; the plant height of the W50 treatment and W60 treatment were 7.3% and 9.27% higher than that of the W30 treatment; irrigation was beneficial to the transfer of photolytic compounds to grains, and the 1000-grain weight of the W50 treatment and W60 treatment was significantly increased by 12.6% and 15.29%, respectively, compared with that of the W30 treatment; the ear grain number, yield and WUE of spring wheat in each treatment showed a trend of increasing first and then decreasing with the increase of irrigation water, and reached the maximum in the W50 treatment, which were 11.74%, 35.95% and 18.24% higher than that of the W30 treatment. Considering the irrigation amount, yield and water use efficiency comprehensively from the perspective of water-saving and high yield, the W50 treatment could be considered as a more suitable irrigation treatment in the late growth period of Hexi spring wheat.

In order to quantify the effects of water and nitrogen stress on dry matter and nitrogen accumulation and distribution of seed maize in northwest arid region of China and to establish a model of dry matter and nitrogen distribution between organs under water and nitrogen stress condition, in this experiment, three irrigation levels were set, namely, full irrigation (W1), mild water stress (W0.75) and severe water stress (W0.5), and three nitrogen application levels were set, namely, 150 kg/hm2(N150), 75 kg/hm2(N75) and 0 kg/hm2(N0), the effects of water and nitrogen stress on dry matter and nitrogen distribution coefficient between organs were analyzed, and a dynamic model of dry matter and nitrogen distribution was established. The results showed that the distribution coefficient of stem showed a single peak curve and the distribution coefficient of stem nitrogen decreased with the growth period. Leaf distribution coefficient and leaf nitrogen distribution coefficient both showed a downward trend. The ear distribution coefficient and the ear nitrogen distribution coefficient increased gradually. In general, the stem distribution coefficient was greater than the stem nitrogen distribution coefficient, the leaf distribution coefficient was less than the leaf nitrogen distribution coefficient, and the ear distribution coefficient was less than the ear nitrogen distribution coefficient. Nitrogen stress had no significant effect on dry matter distribution and nitrogen distribution of seed maize. Water stress increased the distribution coefficient and nitrogen distribution coefficient of stem. The leaf and ear distribution coefficients and leaf nitrogen distribution coefficients under water stress were significantly lower than those under full irrigation. The distribution coefficients of leaf and nitrogen were changed by Logistic function with the effective accumulated temperature. The grain dry matter distribution coefficient decreased exponentially with the effective accumulated temperature. The model can accurately simulate the dynamic change of distribution coefficient during the whole growth period.

Central Yunnan was the major plateau characteristics agricultural products areas in Yunnan province, and the study on irrigation system has an important significance in the local water resources optimal allocation and efficient utilization. Based on the experimental data of Jianshui (102°50′E, 23°56′N) in the south of Central Yunnan from 2016 to 2018, the crop and soil parameters involved in the irrigation calculation module of CROPWAT model were calibrated and the irrigation process of rice and potato during the whole growth period were simulated by the model. The results showed that the water quantity of rice ponding simulated by the model was 192.3 to 195.0 mm; the irrigation times during the growth period of rice after transplanting was 8~11 times, the irrigating quota was 20.9~45.9 mm, the irrigation quota was between 483.3 to 609.7 mm in all growth period, the irrigation ration was 288.3~414.4 mm, and the difference in the irrigation quota between the model stimulation and the test observation was within ±6%; during the whole growth period of potatoes, the irrigation times were 7~8 times, the irrigating quota was 12.7~38.3 mm, the irrigation ration was 181.5~201.0 mm, and the difference in the irrigation quota between the stimulation and the test observation was within ±12%; the simulation of irrigation times was close to the test observation, and the simulated irrigation quota was smaller for rice and larger for potato; there was a slight difference in the irrigation time, but the overall responsiveness was better. It was indicated that the model had better application effect in stimulating the process of irrigation of rice and potato in the south of Central Yunnan and the irrigation schedule developed by the model could improve our grasp of irrigation time and irrigation quota and improve the accuracy of irrigation schedule.

Goji is an important economic crop in Ningxia, while the automation level in its cultivation process is low. Ningxia is located in the northwest of China, its annual precipitation is relatively small, the soil is mainly sandy, water is easy to lose, so Goji drip irrigation is very important. Conventional PID algorithm is difficult to meet the automatic control of Goji drip irrigation. Therefore, a control system based on fuzzy neural network was designed. This system integrated fuzzy control and neural network, and took the deviation of soil moisture content and the variation rate of deviation as input values. After the fuzzy neural network operation, the three input parameters of the PID controller were obtained, and then the Goji drip irrigation control was realized through this PID closed-loop control system. Through the simulation experiments of Simulink, it was verified that the fuzzy neural network PID control had less overshoot and faster response than the traditional PID control.

In order to save water for irrigation in greenhouse, a three-degree-of-freedom upside-down mechanical arm irrigation device that can move along the track was designed. At the same time, the device can ensure that crops grow in the optimal moisture soil, so as to improve crop yield. Also, in this paper, a method for uniform distribution of soil moisture sensors based on potential function and electric potential field theory, which could accurately collect soil moisture in the area was presented, fuzzy control was used to control soil moisture more accurately, and PI method was adopted to control the motor of each joint to respond to the control instruction quickly. The calculation, analysis and simulation results showed that: PI control enabled the device to quickly respond to commands and move, and the response time was less than 1 s; the combination of the method of uniform distribution of sensors with the fuzzy control method of soil moisture could accurately control the opening and closing time of the solenoid valve, and the response time of the fuzzy control was less than 1 s.The whole structure model of the device has been built, the response speed is fast, and the motion path and action can be executed according to the setting.

In karst rocky desertification areas, the conversion of the inaccessible blue water into ecological green water for vegetation growth and utilization is an important way to improve water resource utilization. In this study, based on the actual situation of non-urban areas in Guiyang, the combination of remote sensing analysis, field research and literature data was used to design three blue-green water conversion measures as follows: ① For the atmospheric precipitation, a total of 17 788 small pools for intercepting irrigation were designed on the about 713 km2 dry land in the study area. ② For the vegetation water use, the measures for closing the hills and afforestation were designed, which were distributed in the 937.75 km2 forest and grassland in leakage area with the vegetation cover of less than 50%. ③ For the green water storage, the slope-reforming measures were designed, mainly distributed in the 713 km2 rural dry land, the 1 255.5 km2 vegetation and grassland in leakage area with vegetation coverage of more than 50%, and the typical leakage zone of approximately 123 km2 with vegetation coverage of less than 50% and no vegetation growth from 2003 to 2013. The research and design of the above conversion measures have important practical significance for the exploration of water resources utilization in similar areas.

Ordos City is the most economically developed region in Inner Mongolia and even western China. However, the shortage of water resources has become an important restricting factor on economic development. In this paper, the water resources ecological footprint theory, LMDI model and Tapio elastic analysis were used to calculate the water resources ecological footprint and its influencing factors from 2001 to 2017, and to evaluate the coordination between usage of water resources and economic development. The results showed that: ① the water resources ecological footprint had shown a general trend of increasing with small fluctuation and then decreasing steadily. Among them, agricultural production consumption was the main component. And technical effect was the core driving force to reduce the water resources ecological footprint. ② Water resources ecological deficit, pressure index and the water resources ecological footprint of ten thousand Yuan GDP all presented apparent declining trend. Although the utilization efficiency of water resources increased year by year, the structure of the water resources utilization was not scientific and the water consumption of agricultural production accounted for a very high proportion. ③ There was a stable decoupling state between GDP growth and water consumption. Agricultural water decoupling was better than that of industry. The regression analysis showed the unstability of industrial water decoupling. Therefore, improving industrial structure and optimizing the proportion of water resources by the three major industries should be strengthened so as to reduce water consumption and achieve sustainable use of water resources．