Layout and R&D of soil moisture and drought monitoring websites in Hetao Irrigation District

1 The purpose and significance of the project

Soil moisture monitoring is the basic work for the study of the law of water circulation, irrigation for agriculture and animal husbandry, rational utilization of water resources, and basic information collection for drought relief. Soil moisture and drought monitoring have important guiding significance for crop sowing, yield forecasting and water-saving irrigation, and are indispensable basis for production decisions in irrigation areas. Practice has proved that in the application of crop yield increase irrigation and timely and appropriate water saving technology application and research, monitoring and forecasting of field moisture can not be separated. Monitoring waterlogging and combining it with the water requirements of local crops is the most direct method of accurately managing the amount of water used in the field. It can realize the purpose of scientifically formulating irrigation plans and regulating soil moisture more accurately, so that the crops in the irrigation area can be timely and properly irrigated, and the efficiency of irrigation can be improved, not only saving water but also increasing production.

By constructing a soil moisture and drought monitoring network and analyzing a large amount of basic data collected, the laws of soil moisture content change in the whole irrigation area can be grasped, soil moisture and drought information can be released, agricultural structure adjustment, drought prevention and drought relief actions, and water-saving socialization services can be implemented. Provide scientific basis. Soil moisture and drought monitoring is a long-term task. Through years of data collection and related information accumulation, simple information is transformed into important information resources, laying a solid foundation for the construction of early warning systems for soil moisture and drought in irrigation areas. At the same time, it also has important significance for the sustainable use of agricultural water resources. The instruments used in soil moisture and drought monitoring projects include: soil moisture and drought management systems or soil moisture monitoring systems, which can measure soil moisture in real-time according to soil moisture monitoring standards, and can also monitor soil water potential, temperature and conductivity. And other parameters.

2 The necessity of project research

2.1 Irrigation area differences

Hetao Irrigation District is in the north of Yinshan, and is adjacent to the Yellow River in the south. It is the largest irrigation system in the country. The current irrigated area is close to 66.7 million hm2, and it is about 300 km long from east to west and 60 km wide from north to south. The large irrigated area results in differences in the natural meteorological conditions between the eastern and western parts of the irrigation area (mainly in the meteorological elements such as annual average temperature, rainfall, evaporation, and wind speed); the irrigated area is high in the southeast and low in the northwest, with local highlands and low-lying lands. The groundwater depth in the irrigation area is different, and the soil parent material in the irrigation area is alluvial in the Yellow River. Because the sedimentary environment of the soil parent material is different in the process of soil formation, the soil configuration of the sand and the interbed layer is formed, the western part is sandy and the east part is sticky. In the irrigation area, soil characteristics of “one-step three-for-soil replacement” emerged; the main canal in the irrigation area was divided into groups by large-scale irrigation areas, and each irrigation area was again subdivided into sub-canal irrigation groups. The same round of irrigation area was used for irrigation. The difference in irrigation time is relatively long. Therefore, the spatial and temporal distribution of soil moisture in Hetao irrigation area is more complicated. The layout of soil moisture and drought monitoring network in the irrigation area is an important means to accurately grasp the soil moisture information in the irrigation area, and it is also a necessary measure for long-term accumulation of basic data for the irrigation area. "There is no river cover agriculture without irrigation of the Yellow River." Only scientifically formulating irrigation plans and regulating the soil moisture in the fields more accurately, according to the requirements of suitable water content for different crops at different growth stages, a reasonable irrigation quota can be established so that water resources can be in short supply. Under the situation, Hetao Agriculture will be sustainable.

2. 2 Yellow water reduction

By 2010, the amount of yellow water allocated to the Hetao Irrigation District in the autonomous region will be reduced from the current 5.2 billion m3 to 4 billion m3. The development of water-saving irrigation and the expansion of dual-irrigation irrigation areas in irrigation areas will increase the utilization of water. The only way to achieve sustainable development is to monitor the soil moisture and drought conditions in the irrigation area to provide a basis for formulating a comprehensive water-saving model for the entire irrigation area.

2. 3 Improve Irrigation District Management

The layout of soil moisture and drought monitoring websites in the irrigation areas is one of the important contents of modern large-scale water conservancy informatization construction, and it is also an important indicator to measure the level of irrigation management in irrigation areas. According to the analysis of soil moisture and drought data, the law of temperature, ground temperature, soil moisture content and other agricultural factors in the irrigation area can be timely reflected, and the Irrigation District Public Bulletin can be issued regularly to determine the crop sowing time, forecasting water diversion time, and water diversion amount. The important guiding value will also produce good economic and social benefits.

2.4 Evaluation of Water Saving Effect in Irrigation District

The analysis of soil moisture content factors is the premise of scientific evaluation of water-saving effects in irrigation areas. Through the monitoring of soil moisture and long drought series in irrigation areas, a large amount of basic data can be accumulated to provide valuable basic data for the production, research and management of irrigation areas.

3 Feasibility of project research

(1) Leaders at all levels of the decision-making level in the irrigation area attach great importance to soil moisture content data and have a full understanding of the importance and necessity of soil moisture monitoring. The experimental stations, management offices, and management sections of each irrigation area are located throughout the entire irrigation area. The selection of soil moisture monitoring points and the daily management in the future provide convenient conditions.

(2) The infrastructure of Hetao Irrigation District has been established and formed. The wireless transmission system has formed a network at all levels of the irrigation management organization in the irrigation district, which provides a good basic condition for the soil moisture and drought monitoring system.

(3) The automated equipment (meteorological station, TDR moisture meter) technology used in the soil moisture and drought monitoring system has matured and has been widely adopted at home and abroad.

(4) Self-developed groundwater self-recording water level meter has accurate measurement, convenient data transmission and stable performance, and has been applied in irrigation areas.

(5) The automatic collection and transmission of meteorological elements and TDR moisture analyzer data is the key technology of the monitoring system. Similar data acquisition and transmission technologies independently researched and developed have been successfully applied in water supply projects. Therefore, independent research and development can be applied to The data collected by the automatic weather station and the TDR moisture analyzer achieves long-distance transmission, and has greater economic advantages compared with similar domestic and foreign stereotyped products.

4 Specific arrangements for the project

The project is planned to be completed in three years. In 2008, the preliminary investigation and research of the project was completed, and the layout of two monitoring points in the middle of the irrigation area was completed. In 2009, the two monitoring points in the eastern part of the Irrigation District and one monitoring point (three monitoring points) in the Houqi Banner in the dry and pastoral areas were completed. In 2010, the layout of the remaining monitoring sites was completed. The soil moisture monitoring sites covered the entire irrigation area and the dry and pastoral areas.

5 Technical indicators and monitoring content of the project

5. 1 Technical Specifications

The main technical indicators include meteorological conditions, soil physical properties, soil moisture status, crop types and growth and development status, and groundwater level.

Meteorological observation elements include precipitation, air temperature, atmospheric pressure, humidity, wind speed, surface evaporation, ground temperature, and sunshine.

The physical characteristics of the soil are expressed by the texture of the soil, the structure of the soil, the specific gravity of the soil, the dry weight of the soil, and the porosity of the soil.

The soil moisture constant is an important indicator of soil moisture characteristics. It mainly includes saturated water content, field water holding capacity, withered water content, and appropriate water content in different crop growth periods.

While observing the soil water content, the sowing date of the crop, the growth period of the crop, and the growth and development of the crop were observed. The moisture status of the crop is represented by the grading of pupa, soil, normal, water shortage, and drought.

The change of shallow groundwater level and groundwater depth is one of the important factors affecting the soil moisture content change. Groundwater observation elements include groundwater level, groundwater depth, groundwater temperature, and groundwater quality.

5. 2 main monitoring content

(1) The key technical issues to be solved are automation and remote transmission technologies. 1 Establishment of public opinion monitoring system: It is arranged in the western, central and eastern parts of Hetao irrigation district. There are two monitoring points in each district, one for each round of irrigation and two for irrigation, and six monitoring points. There are 1 point each in the Urad Zhongqi and Urad Rear Banner in the dry and pastoral areas, 2 points in total. Install bleed monitors at all points. 2 soil moisture monitoring: (based on analysis of different plants at different times).

The monitoring depths of the two monitoring points in the mountain and pastoral areas and the four monitoring points in the east and west of the irrigation area (total of six points) are 50 cm. The three-point test method is used to measure three layers of 0 to 10 and 10 to 30, respectively. 30 to 50.

The monitoring depth of the two monitoring points in the middle of the irrigation area is 110 cm. The 6-point test method can be used to divide the monitoring points into 0 to 10 cm, 10 to 30 cm, 30 to 50 cm, 50 to 70 cm, 70 to 90 cm, and 90 to 110 cm. . Soil moisture data are used at regular intervals. The public opinion of each point should be taken several times in succession, and the average value of the same level for several days should be taken as the final result. 3 Set up a small meteorological station in the Hetao Irrigation District to collect daily weather data such as precipitation, temperature, evaporation, sunshine duration, and wind speed. 4 Groundwater level observation wells were set up at each monitoring site to detect changes in groundwater level.

(2) Technical sources: According to the change of soil moisture content at each monitoring point, the impacts (planting structure, irrigation conditions, etc.) on crops (temperature, meteorology, wind speed) were analyzed.

6 Economic and Social Benefits

Through research, we can formulate a scientific irrigation system based on the appropriate soil moisture content for different crops at different growth stages to guide local agricultural production. According to the local meteorology, groundwater, and water availability data, farmers can adjust planting structure, rational planting, and rational irrigation. To achieve the purpose of saving water and increasing efficiency. Its economic and social benefits are obvious.