In order to explore the effects of planting density and drip spacing on the growth of spring corn under filmed drip irrigation, the field experiment of corn “Xianyu 335” was carried out in Minqin area of Gansu province. Three planting densities (A1:97 500 plants/hm2, A2:105 000 plants/hm2, A3:112 500 plants/hm2) and three drip spacings (B1:20 cm, B2:30 cm, B3:40 cm) were set under corn filmed drip irrigation, and nine combinations of experimental treatments were conducted to analyze the distribution of soil water and nitrogen, yield and water use efficiency of different treatments of maize, so as to obtain appropriate irrigation technical parameters. The distribution law of soil water and nitrogen, physiological indexes, yield and water use efficiency of different corn treatments were analyzed. The results showed that: the planting density of corn had no significant influence on the distribution of soil water and nitrogen, but the yield of corn first increased and then decreased with the increase of density. The optimal planting density of “Xianyu 335” was about 105 000 plants/hm2 under mulched drip irrigation. The yield of A2 corn was the highest, reaching 14 585.8 kg/hm2, 4.8 % and 3% higher than that of A1 and A3, respectively. Drip spacing had a significant effect on soil water and nitrogen distribution. The soil water and nitrogen environment provided by different drip spacing for maize growth was different, which affected the water consumption and yield of spring corn. Under the conditions of this test, the larger the distance between the drips, the narrower and deeper the soil nitrate nitrogen distribution. The smaller the distance between the drips, the broader and shallower the soil nitrate nitrogen distribution. The highest yield of maize was B3, which was 15 615.0 kg/hm2, 17.8% and 11.6% higher than that of B1 and B2, respectively. A2B3 had the highest yield of corn and the maximum water use efficiency. The combination of corn “xianyu 335” with a planting density of 105 000 plants/hm2 and the drip spacing of 40 cm had the best effect, they were more suitable for promotion and application in Minqin area of Gansu province.

The effects of trace irrigation on cotton growth, quality and yield were studied by field plot experiment. Totally 16 treatments were set up, including CK (drip irrigation under film), T1, T2, T3, T4 and T5 (buried depth 30 cm, water volume 3 600, 3 300, 3 000, 2 700, 2 400 m3/hm2), T6, T7, T8, T9, T10 (buried depth 40 cm, equivalent water volume), and T11, T12, T13, T14, T15 (buried depth 50 cm, equivalent water volume). The analysis of 15 agronomic characters of cotton under different treatments by combining principal component and membership function showed that, lint yield, uniformity index, breaking ratio strength, elongation and micronaire can be used for the comprehensive evaluation of the cotton properties. The order from large to small of the average membership function of the main characters under different treatments was CK, T11, T4, T1, T2, T6, T12, T8, T3, T13>T9, T15, T7, T5, T14, T10, which indicated that when the irrigation water amount was 3 600 m3/hm2, the comprehensive effect of drip irrigation is larger than that of trace irrigation. The order of comprehensive effects of trace irrigation with different pipe buried depths was ranked as 50, 30, 40 cm. From the aspect of water saving, the trace irrigation with 30 cm pipe buried depth and 2 700 m3/hm2 irrigation water amount had the best effect.

In order to explore the influence of different fertilizer concentration on the flow rule of apple trunk under the condition of water storage pit irrigation, 4 treatments were set with fertilizer concentration (0, 0.602, 1.204 and 2.408 gN/L) as variables. Thermal diffusion probe (TDP) was used to measure stem flow and analyze its variation. The results showed that: under the conditions of this experiment, the flow rate of the trunk and stem of each fertilization treatment in the water storage pit irrigation increased significantly after fertilization, and the diurnal peak value increased significantly, reaching the peak value on the 18th day after fertilization. The daily peak value of stem flow rate of apple trunk was consistent with the change curve of transpiration rate of leaves, which showed a change rule of first rising and then falling, and reached the maximum value on the 18th day after fertilization. The accumulation of daily stem flow increased with the increase of fertilizer concentration after fertilization. Six kinds of mathematical models were selected to simulate the process of daily accumulation of apple trunk flow, and all of them obtained significant fitting effect, with Richards model having the best fitting effect. In this experiment, D3 treatment (1.204 gN/L) was more conducive to improving the flow rate of apple trunk.

In order to save time and effort and obtain high precision of soil water characteristic curve, 241 field undisturbed loess soils of six textures in the Loess Plateau were used as research objects. The soil water characteristic curve of undisturbed loess was determined by HYPROP instrument, and applied in Hyprop Fit software. Different models were used to fit the measured soil water characteristic curves, and the soil water characteristic curve model parameters of each soil sample were determined. The water content corresponding to the measured soil suction was calculated by the model and compared with the measured values. Finally, the Frelund-Xing model was selected as the optimal prediction model for the soil water characteristic curve of undisturbed loess.

In order to investigate the flow-measuring mechanism of the float lift gate, this paper analyzed the hydraulic characteristics of the float lift gate and derived the flow formula theoretically. The contrast result between the measurements and the calculations showed that the flow formula had high accuracy and simple form. And the flow formula was suitable for the flow measurement in the minor channel. Meanwhile, numerical analysis was used to simulate the flow field under different flow rates and gate openings. The water surface line, velocity structure of different sections, Froude number before the gate and flow measurement precision of the gate were discussed as well. The results showed that the simulated flow and water depth were in good agreement with the measured flow and water depth; the Froude number before the gate obtained by experiment and numerical simulation was less than 0.5, which can meet the flow measurement requirements.

Soil infiltration is the key factor affecting the process of rainfall runoff and soil erosion. In order to study the effect of grazing intensity on the soil infiltration and soil-water conservation ability of meadow steppe, the HulunBuir grassland with different grazing intensity was selected as research object, the soil infiltration process of grazing grassland, medium grazing grassland and heavy grazing grassland was determined by double-ring infiltration experiment, and the infiltration characteristics and influencing factors were analyzed. The results showed that the soil infiltration rate of the three grazing intensity grasslands was significantly different, with the highest soil infiltration rate of the non-grazing grassland and the lowest soil infiltration rate of the heavily grazed grassland. The main factors affecting soil infiltration were initial soil moisture content, soil bulk density, total soil porosity and non-capillary porosity. The four factors were significantly correlated with the initial soil infiltration rate, temperature infiltration rate and cumulative infiltration rate, and the correlation coefficient was all above 0.69.Four infiltration models were used to simulate the infiltration process of grassland soil with different grazing intensities. It was found that the Horton model could better describe the change process of infiltration rate with time, and the simulation effect was the best.

Spatial time-varying characteristics of soil moisture content in farmland have important effects on soil moisture monitoring and irrigation prediction. Two sets of soil moisture monitoring systems were set up in the two trial areas of Beijinzhuang and Xilv village, Wuqing district, Tianjin. Each system included one base station and three measuring points. Each measuring point was connected to two soil moisture sensors (buried 30 cm and 60 cm below the surface). The data of soil moisture content at two depths were measured, the average moisture content of 0~60 cm was calculated by linear formula, the variation characteristics of coefficient of variation (CV) of soil moisture content over time were analyzed by statistical method, and the correlation between soil moisture content at the test points was analyzed. The results showed that CV changed significantly with time. When CV changed a lot, soil moisture content in the corresponding period was small, usually during irrigation. When CV changed small and soil moisture content was large, it was generally in periods of high rainfall. CV showed weak and moderate variation in this test area. The correlation coefficient could reflect the spatial variability to certain extent. With the increase of the research scale, the correlation coefficient of soil moisture content between the measurement points decreased.

In this paper, the effects of irrigation amount and irrigation method on tomato yield and water productivity in greenhouse were studied through meta-analysis, in an attempt to find the key factors to improve tomato yield and water productivity. Literature on greenhouse tomato planting in different parts of China published in CNKI and Wanfang database from 2000 to 2015 was used as the data source. The results of meta-analysis on 43 literatures included in this study showed that the irrigation volume of greenhouse tomato with high yield and high water productivity ranged from 3 500 to 4 500 m3/hm2, and the best irrigation method was pipe irrigation. The results were comparable with those of other field experiments, and provide theoretical support and practical guidance for selecting irrigation water and irrigation methods for greenhouse tomatoes, improving the planting level of greenhouse tomatoes, improving water use efficiency and reducing water resource waste.

At present, there are few researches on the distribution of agricultural water rights among farmers in irrigated areas and the current distribution model is unreasonable. From the perspective of fairness, based on the agricultural population and irrigated area of farmers in irrigated areas, this paper studied the distribution of agricultural initial water rights among farmers driven by agricultural water-saving. And the Gini coefficient method was used to construct the model of agricultural initial water right distribution among farmers in irrigated areas. An example analysis was conducted by the pastoral team (4) of ShenWu main canals in Hetao irrigation area. The distribution results showed that the model was more equitable than the current distribution and could provide some technical support for water rights distribution and transaction in irrigated areas.

Soil moisture is an important parameter for agricultural production. Efficient and accurate monitoring of soil moisture is an important part of ensuring agricultural production safety. For the soil moisture monitoring methods based on vegetation index, how to select the optimal vegetation index according to the difference of region and plant growth period is the key problem. In this paper, using the measured farmland moisture data and MODIS remote sensing data of the main winter wheat producing areas in the Huang-Huai-Hai Plain in the central and eastern Henan Province from February to June 2015, the correlation between normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), vegetation water supply index (VSWI), temperature vegetation dryness index (TVDI) and soil water content was analyzed, the responses of different vegetation indexes to soil moisture content at different depths was compared, and the regression models of four mulch indexes and soil moisture content were established to analyze the prediction accuracy. The results showed that: in this study, TVDI had the best correlation with soil moisture and the highest prediction accuracy. Each index had the best correlation with soil moisture at 10~20 cm depth and the highest prediction accuracy. Therefore, TVDI was the optimal response index, and the soil moisture at 10~20 cm depth was the optimal response depth.

Due to the small flow channel of emitter, drip irrigation system has a high requirement on water quality, so filter device is very important in drip irrigation. Domestic and foreign scholars have done a lot of research and development work on it. In this context, on the basis of briefly describing the working principles of sand media, screen, disc filters and hydro-cyclone sand separators for drip irrigation, this paper systematically summarizes the research status of filters for drip irrigation, and discusses the existing problems and development trends of filters. The paper holds that there are many experimental studies on the variation law and influencing factors of water head loss and blockage in filters. The fluid calculation model has been introduced in the aspects of establishing the theoretical calculation equation of the filter head loss and simulating the flow pattern inside the filter. And the filter material and filter cap of sand filter, the self-cleaning device of screen filters, the disc of disc filters, the structure improvement of integrated filter are the hot research and development of filters. It is suggested that the research and development of filters in the future can focus on the simulation technology of filters and the development of filters suitable for China's national conditions. This study can provide some technical support for the research of drip irrigation filter.

The level of agricultural water prices directly affects the enthusiasm of farmers to grow grain, thus affecting the country's food security. The agricultural water price calculation model for agricultural water rights allocation was studied in this paper, and the agricultural water price calculation model under long-term water rights and the agricultural water price model under short-term water rights were established. Based on the economic carrying capacity of farmers, a dynamic coordinated water price model based on different hydrological years under water rights allocation was proposed and applied in Shandong-Huantai project area. The results showed that with the change of actual water intake of farmers, the agricultural water price in wet years varied from 0.268 to 0.54 yuan/m3, the agricultural water price in normal years varied from 0.163 to 0.606 yuan/m3, and the agricultural water price in dry years varied from 0.113 to 0.938 yuan/m3. This study results indicate that the dynamic coordinated water price model considering the change of water volume in different hydrological years can better reflect the actual situation of farmers' water use in different hydrological years, and is more conducive to improving farmers' enthusiasm for water conservation and implementation of agricultural water price, and has important guiding significance for promoting regional agricultural water price reform.

In order to study and improve the ET inversion accuracy of RLPM model, and explore the influence of various meteorological parameters and remote sensing parameters on the time-scale variation law of ET inversion value, based on the RLPM inversion model, this paper adopted the improved Morse classification screening method to analyze the sensitivity of ET values of 98 sites on the loess plateau from 2010 to 2015 to the changes of NDVI, relative humidity, sunshine duration, temperature and solar radiation at monthly and annual scales. The results showed that except relative humidity, the absolute value of sensitivity coefficient of each factor reached the highest value in summer, while the sensitivity coefficient of relative humidity reached the highest value in winter. ET inversion values had the highest sensitivity to solar radiation, followed by NDVI and sunshine hours, and the lowest sensitivity to temperature and relative humidity.

Research on factors impacting farmers' choice of high-efficiency water-saving technology is vital for understanding farmers' irrigation behavior and promoting the popularization of high-efficiency water-saving technologies. Based on a questionnaire survey of 496 households in three counties (districts) of Shiyang River Basin, this paper used binary logistic regression model to study the impact of five factors, including individual factors, family factors, resource endowment factors, policy and system factors and cognitive factors, on farmers' choice of efficient water-saving technology. The results showed that age, degree of land fragmentation, degree of part-time employment, local water resources abundant and farmers' risk perception had certain adverse impacts on the choice of water-saving technologies. The scale of land, the perfection degree of agricultural water infrastructure, supporting policies, and the rationality of agricultural planting structure, water pricing method and the development degree of water rights trading could promote the adoption of water-saving technologies. It is suggested to improve the allocation of water rights, promote the reform of water prices, improve the incentive mechanism for water-saving, and speed up the construction of water rights market, so as to increase the enthusiasm of farmers to choose efficient water-saving technologies.

At present, there are few devices for measuring evapotranspiration of potted plants in China, and all of them are single point measurement, and commercial electronic scales are mostly used in potted science experiments. In this paper, an online measurement system of evapotranspiration of multi-path potted plants based on Lora wireless technology is developed.The maximum error of the weighing unit within the range of 0~30 ℃ temperature and online weighing for 15 consecutive days is no more than 1 g. The node can work continuously for more than 120 days with a sampling interval of 5 minutes. The experiment of potted lettuce in the greenhouse showed that the evapotranspiration rate of potted lettuce presented a peak curve during the day. The order of evapotranspiration rates at each growth stage was ranked as middle, late, early stage. The linear correlation between evapotranspiration rate, solar radiation and atmospheric saturation vapor pressure was 0.86 and 0.78, respectively. The measured results of the system were basically consistent with the existing studies, which could better reflect the change trend of evapotranspiration of potted plants during the whole growth cycle, and provide high-precision and highly reliable intelligent equipment support for online multi-point monitoring of plant evapotranspiration.

On the basis of the independent developed light simple intelligent irrigation fertilizing machine by ourselves, and embedded in the intelligent irrigation system based on the light radiation, the field effect experiment was carried out on the soil-cultivated tomato. The results showed that the soil moisture content of 0~60 cm soil layer managed by the fertilizing machine was kept between 30% and 40%, which ensured that the soil of tomato root layer was always in the appropriate water range. Compared with conventional artificial management, the quality of tomato could be improved, and the economic benefit could be increased by 9.89%, which could achieve the purpose of saving water, saving fertilizer, saving labor, improving quality and increasing efficiency.

The structure, the suitable crop height and the operation occasion of the sprinkler vehicle of the winch sprinkling irrigation machine were studied in this paper. According to the existing adaptability problems and practical needs, the structure of sprinkler vehicle was optimized and improved. By comparing and analyzing various schemes, the optimal scheme was confirmed as pinion and rack structure, and the heightening device was designed. The suitable height range of the heightening device and the output torque of the reducer were calculated. The working principle and using method of the heightening device were explained in detail. The theoretical basis for the selection of reduction gear box was studied, the prototype was trial-produced, several rounds of field tests were carried out on the prototype, and the precautions for use were put forward.

Aiming at the problems of leakage spray, overlap and out-of-band spraying of sprinkler head in the market, a three-section tubular non-circular spray field sprinkler head was developed in this paper. The sprinkler head was composed of a tube body with three end faces being round and the adjacent axis had an angle. Each section of the pipe body was connected by bearings to form three pairs of rotating pairs. The first section of pipe body was connected with the mounting base, and the rotation rate was controlled by a motor. The pipe body controled the rotation speed of the sprinkler, and the angle difference between the rotation center line of the pipe body and the sprinkler axis was changed by another motor to realize a wide range of angle change of the sprinkler elevation angle, thereby accurately controlling the nozzle to achieve uniform, standard non-circular spray. While ensuring the low economic cost of the sprinkler, the elliptical cylinder design with rounded ends was convenient to add different types of regulators to the sprinkler inlet and outlet, and comprehensive mature non-circular irrigation control measures to meet the sprinkler irrigation under different environments. After testing, the device was superior to the traditional sprinkler in every terms, which provided a new idea and method for the design and application of non-circular spray field sprinkler head.