In order to further improve the monitoring accuracy of soil moisture, the influence of different sampling methods on soil moisture observation was analyzed on the basis of field experiment. The observation accuracy of different sampling methods was evaluated by using the sampling results of ring knife as controls.The results showed that under the condition of loam and clay, the accuracy of the all-drilling superfluous part removal method was higher. Under different sampling conditions, regardless of the level of soil moisture treatment and the depth of the excavation level, the all-drilling superfluous part removal method was more accurate.

Soil moisture migration rules under different negative pressure irrigation are studied based on the indoor experiments． The results indicate that the geometry of the wetted soil under negative pressure irrigation can be best represented by a truncated ellipsoid; both the cumulative infiltration and migration of wetting front have the significant power function relationship with time with Ｒ is more than 0．99; the infiltration ration decreases with the increase of the absolute pressure value，the infiltration ratio of the －5 kPa treatment is 80% of CK，the infiltration ratio of －10 kPa is 67% of CK and the infiltration ratio of －15 kPa treatment and －20 kPa treatment is 57%; the horizontal and vertical migration speed of wetting front decrease with the increase of the absolute pressure value; comparing with control，the vertical wetting front of －5 kPa treatment delays 2 days to reach the bottom，the －10 kPa treatment delays 5 days，the －15 kPa treatment delays 8tdays and the －20 kPa treatment delays 12 days; with the decrease of the water potential control，the soil water content changing range increases，while the lower limit of soil water content decreases．

In order to explore the migration rules of soil water and salt in field under different furrow irrigation modes，the HYDＲUS-3D software was used to simulate the migration rules of soil water and salt under alternate furrow irrigation ( AFI) ，conventional furrow irrigation ( CFI) and Fixed furrow irrigation( FFI) based on a field experiment in Jingtaichuan electric pumping irrigation region in Gansu Province． Then the field experiment data was used to verify the simulation results． The results showed that the variation tendency of soil water content in all soil layers under different furrow irrigation modes were basically identical，and that in deep layer under CFI was about 32% and higher than that of other two modes; the furrow irrigation mode and the irrigation amount both had significant influence on soil salt，and with the increase of irrigation amount，the effect of salt leaching became more and more obvious; analyzing from long period of time，the soil salt accumulated in different degree; in 0 ～ 20 cm layer the salt deposition rate of CFI，FFI and AFI was 22%，26% and 10%，respectively; moreover，AFI was the best in controlling the accumulation of salt．

In order to investigate the effect of soil bulk density on infiltration and water and nitrogen distribution under water storage pit irrigation． An indoor experiment was conducted by suing a 30°wedge-shaped plexiglass soil container with the height of 120 cm and the radius of 100 cm，which represented one-twelfth of the complete water storage pit． Three soil bulk density，including 1．3，1．4 and 1．47 g /cm3 ，were used． The influence of soil bulk density on water infiltration，water distribution，ammonium nitrogen and nitrate nitrogen were explored． The experimental results showed that the cumulative infiltration decreased with the soil bulk density increase，and the relationship between the volume and time of cumulative infiltration was accorded with Kostiakov model． Soil wetting body was smaller when the soil bulk density was larger，the soil volumetric water content in 0 ～ 60 cm depth increased with the increase of soil bulk density． The variation of ammonium nitrogen of different soil bulk density was not consistent with radial distance． The accumulation of nitrate nitrogen in deeper wetting front for different soil bulk density followed the trend of 1．47 g /cm3 ＞1．4 g /cm3 ＞1．3 g /cm3 ． 

In order to acquire water holding capacity and water movement parameters of unsaturated soil，based on the data of soil moisture characteristics curve of the loess，the prediction models are established by using BP Neural Network，in which physical and chemical parameters are chose as input variables and the Gardner model parameters are chose as output factors． The average relative errors of the two parameters are both below 6%． The prediction accuracy of the two models can both meet the application requirements． The results show that it is feasible to choose soil texture，bulk density，organic matter and inorganic salt contents of soil as input variables to predict the SWCC Gardner model parameters and it is reasonable to use BP Neural Network to establish predictive models for SWCC Gardner model parameters． The research can provide reference for obtaining the water retention and water movements of vadose soil in the Loess Plateau region.

Through laboratory test，this paper studies three wildly used types of drip irrigation belt ( pipe) ，including single wing labyrinth drip irrigation belt，the chip drip irrigation belt and the mosaic column emitter type drip irrigation pipe． The subsurface drip irrigation experiments have been respectively conducted on the typical soil，including clay loam，loam and sandy loam，in Inner Mongolia． The relationship of water movement，drip irrigation belt discharge and soil property is analyzed，the basic rules of moisture movement in different soil are obtained，and the applicability of different kinds of drip irrigation belt ( pipe) flow in different soil is analyzed，which lays the foundation for primary selection of drip irrigation belt for users． 

In order to study the effect of different soil types on heat and moisture transfer，a one-dimension soil column experimental platform is constructed，and 6 kinds of soil samples，such as gravel sand，coarse sand，middle sand，fine sand，silt and clay，are selected to study the rules of heat and moisture transfer． The experimental results show that: under the condition of the initial water content of 5%，the heat source temperature of 30 ℃ and the compaction work of 20J，there are some differences for heat transfer in 6 kinds of soil samples during the heating process; the silty sand，fine sand and clay have the best heat transfer effect，the second is the gravel sand and coarse sand，and the heat transfer effect of the middle sand is the worst; in the heat-affected radius，the conduction of heat in soil and the transfer of water content are mutually driven; the closer the monitoring point to the heat source，the more the temperature gradient becomes the main driving force for the migration of water in soil samples，and the farther away from the heat source，the more the humidity gradient becomes the main driving force of the temperature conduction． The difference of the heat and moisture transfer of soil types and the driving mechanism of heat and moisture transfer in unsaturated soil can provide some reference for solving the problems of heat and moisture transfer in different soils． 

In order to study the variation characteristic of precipitation in the Aibi lake oasis，according to the monthly precipitation data from four meteorological stations during 1960 to 2013，the climate trend analysis method，Mann -Kendall Mutation Test Method，the Wavelet Analysis Method and GIS Spatial analysis are used to comprehensively analyze the tendency，mutability and periodicity of the precipitation of the oasis in recent 54 years． The results show that: in recent 54 years，the annul precipitation of Aibi lake oasis increases at the rate of 7．95 mm/10 a，the change trend of the seasonal precipitation is consistent with annual precipitation，the change characteristic is slight increasing in spring and autumn and strong increasing in summer and winter． Through the Mann-Kendall Mutation Test，it is found that an increasing mutation of the annul precipitation appeared in 1986 in Aibi lake oasis，while there has no obvious trend changes of the precipitation of the basin． Through wavelet analysis，it is found that the precipitation of Aibi lake oasis shows multiple time scale change features in long time sequence and the variation is large． In general，the climate in Aibi lake Oasis changed to be more humid in recent 54 years．

Agricultural water consumption accounts for more than 60 percent in China ＇ s total water consumption，while irrigation water consumption accounts for more than 90 percent in that of agricultural water． The value of Effective Utilization Coefficient of Irrigation Water of Farmland in China is only 0．53，so it is necessary to analyze the agricultural water balance so as to effectively promote water conservation． Firstly，based on the analysis of agricultural water supply and demand，taking an agricultural project area of Nanjing as an example，the agricultural water consumptions before and after agricultural planning are compared． Combined with industrial structure adjustment and agricultural water-saving technology，supply -demand balance of agricultural water resources in agricultural project area is estimated and forecasted in different level years． Secondly，the contradiction between supply and demand of regional agricultural water resources is discussed，and the countermeasures，including constructing farmland water conservancy project，implementing water -saving irrigation technology and reasonably raising water price，are put forward． 

To explore the effect of biochar application on CH4 emission from paddy fields with water saving irrigation，a field experiment was conducted． Based on it，the variation of CH4 fluxes and emissions were illuminated and the rice yield and irrigation water productivity were analyzed． The results showed that the CH4 emission from paddy fields concentrated on the rice early growth stage ( before 40 days after transplantation) ，and it maintained at a low level after 40 days after transplantation． Before 20 days after transplantation，the application of biochar increased CH4 fluxes from paddy fields under water saving irrigation paddy while decreased it after the stage． Both medium and high amount of biochar ( 20 t / hm2 and 40 t / hm2 ) application decreased the total CH4 emissions，and the decrease rate was 29． 8% and 6． 3% respectively compared to the control experiment． Meanwhile，the rice yield and irrigation water productivity increased by 9．3% ～ 15．9% and 15．1% ～ 15．9% respectively． The result of the experiment showed that the application of biochar on paddy field under water saving irrigation could reduce the CH4 emission，decrease irrigation water input and increase rice yield．

This paper uses Morelet wavelet and dbN wavelet to analyze the precipitation cycles in multi -time scales and variation trends according to the precipitation data of 55 years of 4 precipitation stations in Jilin City． The study results show that the precipitation of Jilin City has 2 to 6 years of short cycle and 22 to 25 years long period; there are small fluctuations in 10 to13 years; on long time scale，the annual precipitation of Jilin City presents the trend of gradually increasing recently to a maximum，and then gradually decreasing．

Trace quantity irrigation is a new water-saving irrigation method developed based on membrane filtration technology in recent years． Its core element is PTFE membrane． It has excellent mechanical property，ageing resistance and chemical stability，etc． But the membrane is contaminated easily because of the hydrophobic property，which poses a big threat to the long-term stability of the trace quantity irrigation operation． An experimental study on hydrophilic and antifouling property of PTFE membrane is conducted in this paper． The results show that composite membrane has good hydrophilicity and pollution resistance property，and the dopamine polymer solid adsorbs on its surface． The lifetime of PTFE membrane and the operation reliability of trace quantity irrigation are improved in a great extent． The study results can provide technical guidance for development and application of trace quantity irrigation．

In this research，with the local farmers conventional fertilization and irrigation practice as contrast ( CK) ，a field experiment was conducted to study the effects of reducing nitrogen and phosphorus fertilizer and pond aquaculture wastewater irrigation on crop yield，nitrogen uptake quantity and nitrogen distribution of 0 ～ 60 cm soil layer． The results showed that under the condition of pond aquaculture wastewater irrigation，the yield of the conventional fertilization treatment was the highest，which was higher than CK treatment by 2．3%，the nitrogen and phosphorus uptake quantity was increased by 4．4 and 2．0 kg / hm2 ，respectively; for the 80% conventional fertilization treatment，its yield and nitrogen uptake quantity was similar to that of CK; while for the 60% conventional fertilization treatment，its yield，nitrogen and phosphorus uptake quantity decreased significantly than that of CK; in the rice growth period，the nitrogen uptake quantity of top soil layer of the 100% CF，80%CF and 60%CF treatment was averagely increased by 3．8%，－2．3% and －10．1%，respectively，and the phosphorus uptake quantity was averagely increased by 3．3%，－4．2% and －10．7%，respectively; for all the treatments，the total N，the available N，the total P and the available P content decreased with the increase of soil depth in 0 ～ 60 cm soil layer，and decreased with the decrease of fertilization for the same soil depth． So the pond aquaculture wastewater irrigation with reducing nitrogen and phosphorus fertilizer did not increase the nitrogen and phosphorus content in soil profile． Comprehensively considering the crop yield benefits and environmental risk of soil nitrogen and phosphorus accumulation，the pond aquaculture wastewater irrigation can save chemical fertilizer by 20% and freshwater quantity by 5 700 m3 / hm2 during the whole rice growth period．

According to the influencing factor characteristic and the change rule of water consumption, which is the red line of water resources development and utilization in the most stringent water management system, this paper puts forward a comprehensive analysis method of time difference correlation analysis and multiple regression model. This method establishes the multiple regression model to predict the total water consumption, based on the time difference correlation analysis to identify the forward-looking factors. Taking Taihu Basin as an example, use time difference correlation analysis to filter out eight indicators related to the water consumption, including the population, industrial structure ratio, farmland area, water use per capita, industrial water consumption and so on. And then a multiple linear regression model is constructed by SPSS19.0, which has good fitting degree and precision, to predict and analyze the water consumption of Taihu Basin in 2015 and 2020. In all, this method and the calculation results can provide reference for evaluation of water resources carrying capacity of Taihu Basin.

To solve the layout of soil moisture sensors for variable rate water operations in intelligent greenhouse system，an optimal placement based on regular grid and Delaunay triangulation algorithms is proposed． In this approach，the soil of the greenhouse planting area is separated into several square grids by regular grid method，and Delaunay triangulation is carried out for each square grid． Considering the spatial variability of soil water content，the triangular lattice is restricted by using the coefficient of variation，and the triangular mesh with large local variability is subdivided to realize the distribution of soil moisture content in a small amount of sensors． The coefficient of variation coefficient of soil water content is determined by MATLAB． The sampling value of the final deployment point is verified by Kriging interpolation and the three-dimensional distribution of the actual soil water content． And the correctness of the algorithm is verified by the experiment，which lay the foundation for the greenhouse water variable operation．

Pressure differential tank is the most widely used fertilizer equipment． Its export concentration varies with the factors such as pressure and fertilizer amount，which has a direct impact on the fertilization quality and system operation stability． In this paper，through controlling different fertilization and pressure conditions，the experiment was carried out at the outlet of the fertilization tank． The fertilizers amounts of 1．0，1．5，2．0 kg were used，and the pressure differentials changed from 0．03 to 0．15 MPa with an incremental interval of 0．03 MPa． The results show that the flow rate at the outlet of the fertilizer tank increases exponentially with the pressure difference of the fertilizer tank． The concentration of fertilizer solution decreases with the time，which decreases significantly in the first 10 min and becomes stable after 20 min． The appropriate one-time fertilizer amount is in the range of 1．0 to 2．0 kg，excessive amount will result in that the total fertilization lasts too long time and part of the fertilizer still can not be dissolved even at the end of the fertilization． The main factors affecting the fertilization time include the fertilizer amount and the pressure difference． The fertilization time has a power function relationship with the fertilizer amount and the pressure difference．

Surge irrigation technology ( SIT) has been studied for many years． However，the field irrigation equipment has not been matched reasonably at present，which limits the development and application of SIT． A hydraulic automatic surge irrigation equipment based on double floater is developed in this study to improve the irrigation efficiency at the area of canal irrigation and low-pressure water transferring pipes irrigation． The equipment with mechanical control unit of double floater is operated by water buoyancy for automatic surge irrigation． The equipment is characterized by stable operation，low investment，water resources conserved，labor-saving，hydraulic automatic and can meet various requirements of surge irrigation in practice． It＇s very suitable for the surge irrigation district in our country to promote the efficient use of water resources．

In view of problems，such as lag in irrigation technology and lack of efficient means，which lead to poor irrigation accuracy and serious waste of water resources in large cultivation areas，a remote intelligent irrigation control system based on IOT in facility agriculture is developed． In this paper，a wireless sensor networks ( WSN) is presented to obtain soil moisture information and propose the communication mode of the fusion of ZigBee network and GPＲS． The fuzzy control algorithm is used to deal with the soil moisture information to calculate irrigation quota precisely． The monitoring interface is designed based on Kingview6． 55，including parameters monitoring，data analysis， network communication and management decision． The experimental results show that the system can drive irrigation equipment quickly and precisely without human intervention to ensure that the crops grow under the best conditions，which will improve the utilization of water resources． Meanwhile，the system has good instantaneity and application prospects． 

Solving the inverse problem of soil water characteristic curves is an important part for the investigation of water and salt movement in unsaturated soil． Traditional soil moisture inverse solutions ( gradient -based nonlinear optimization problems) generally have three disadvantages，such as slow convergence rate，low accuracy，and frequent occurrence of local minimum solutions． The bio -inspired optimization algorithms，such as firefly algorithm and particle swarm optimization which are developed by mimicking the animal behaviors and evolution characteristics，Hierarchical Bayesian Method which is based on conditional probability and Ensemble Kalman Filter which is based on sequential data assimilation method，all have strong capacity to search the global optimal solutions with good efficiency． The application of the new algorithms for solving the parameters inverse problem of soil water characteristic curves indicates that the new algorithms can discover globally optimal solutions with larger probability and faster convergence． According to the algorithm theories and their application effects，the intelligent algorithms have broad prospects for solving the parameters inverse problem of soil water characteristic curves

In order to improve the extensive management of agricultural greenhouse soil moisture, we design a league building greenhouse intelligent irrigation system based on ZigBee technology. The system consists of terminal data acquisition control module, ZigBee wireless network transmission system, PC management system and mobile APP terminal. Managers can view the soil moisture and temperature data on the PC in the office or on the phone APP, according to the judgment of the data fusion, managers can automatically or manually control the irrigation drip irrigation system, so as to realize the agricultural science, automated and meticulous management. In order to improve the stability of the system, Wireless network modes are mainly discussed in this paper. The test of nearly 200 acres of grapes in greenhouse field shows that the system has good stability, its functions meet the design requirements, and it has the very good application prospect and popularization value.

In order to improve the drought disasters risk assessment and emergency management capability of Yunnan，based on the natural disaster risk theory，a risk drought disaster assessment model，in which four indexes including the hazard of the disaster-causing factors， vulnerability of disaster-prone environment，exposure of drought disaster -affected bodies and the ability of disaster prevention and reduction are considered，is established by considering the comprehensive effect of meteorology，geographical environment and social factors． The AHP method is used to calculate the weight of each evaluation index and the drought disaster risk degree zoning map is drawn based on ArcGIS． The results show that: the drought disaster risk zone is spatially distributed in“sheet”shape，that in northeast and southeast is higher than that in northwest and southwest; the high and sub-high drought disaster risk areas contain Zhaotong，Huize in northeast of Yunnan and Luxi， Guangnan in southeastern of Yunnan． Dali，Baoshan and most of the central areas are medium risk areas; the low and sub-low risk areas contain Gongshan，Weixi in northwest of Yunan and Jinghong，Lancang in southwest of Yunnan． The result of comparing the evaluation result with the total economic losses of drought disaster areas shows that the model can reflect the damage characteristic of drought in Yunnan and provide advisory advices for further study of drought disaster risk assessment．