Sand and gravel filter manufacturers talk about the application of underground drip irrigation technology

Subsurface drip irrigation has developed relatively quickly, but the relative area is small, limited only to cotton irrigation.

    Subsurface Drip Irrigation (SDI) Skills and Features

    SDI is an irrigation method that slowly delivers water or a water-fertilizer mixture through buried emitters into the soil of the crop root zone. Then, the water is dispersed to the root layer through capillary action or gravity for absorption and use by the crop.

    Compared with other irrigation methods, SDI has significant advantages: it significantly saves water, increases fertilizer utilization, and can optimize crop quality and increase yields. SDI technology also operates at low flow rates and low pressure heads, saving operating costs and energy, and the system has a relatively long lifespan. However, there are shortcomings, mainly the problem of emitter clogging. In addition, since the subsurface drip irrigation tubing is buried at a certain depth, the topsoil is often drier or insufficiently watered, which will affect seed germination and emergence, and the uniformity of irrigation is also difficult to control.

 Issues to Note in Subsurface Drip Irrigation (SDI) Project Planning

    (1) Currently, the challenge in project planning is that the irrigation area controlled by the system is constantly increasing, and the problem of using small-system planning theories and methods to plan large-scale irrigation systems is particularly prominent; (2) Currently, there is no mature professional planning software for project planning. In particular, there is even less software for water-saving irrigation project planning in Xinjiang. For example, in terms of pipeline layout and hydraulic calculation methods, the layout of the water transmission pipeline into a ring network (especially for single-well drip irrigation) is conducive to the uniformity of irrigation, and at the same time, it increases the system's water supply security rate. Its hydraulic calculation can use the water supply pipe network hydraulic calculation software commonly used in municipal engineering; (3) Two planning concepts about irrigation principles. One is the concept of insufficient irrigation: the purpose of irrigation is not to achieve the highest yield per unit area, but to make the crop yield per unit of water higher. For example, the use of sitting water planting and key watering are prototypes of this irrigation principle; the other is shallow water rice wet-dry irrigation: its basic approach is thin water transplanting, shallow water turning green, field wetness management in the early stage of tillering, sun-drying in the late stage of tillering, maintaining thin water during jointing and heading, and keeping the field wet during milky and ripe stages, and dry ripening; (4) Selection of pipe parameters. The depth of the buried pipe is usually 20～70cm, which is most suitable. For fruit trees, the burial depth is around 40cm; cotton is preferably 10～20cm; 40cm on heavy clay soil is a better burial depth for winter wheat using subsurface drip irrigation. The spacing of the pipes is usually 0.25～5.00m. For pasture, 60cm in sandy loam is suitable, but for clay, it requires more; for corn spacing, 1.5m is the optimal distance.

    Solutions to Some Prominent Problems of Subsurface Drip Irrigation

    (1) Irrigation water should usually be settled first to remove large particles of sediment and then filtered to remove fine particulate matter. When designing the tubing, use emitters with a larger flow rate to reduce clogging. In the case of flat terrain and poor water quality, for ease of management, install longer tubing, and prioritize the use of pressure-compensating emitters. In addition, in order to prevent crop water-seeking behavior from affecting crop root growth, deeply buried tubing is recommended; (2) To prevent emitter clogging, install air valves in the system and regularly add herbicides to the irrigation water; for pressure-compensating emitters, micro-tube emitters and other types of emitters, in order to reduce the probability of tube clogging, the tube length and diameter, emitter spacing, etc. should be minimized in practice, and the emitter flow rate should be increased as much as possible; (3) Install inlet and outlet air valves at the high point of the system to prevent negative pressure from causing emitter clogging when irrigation is interrupted. In mountainous and hilly areas with large elevation differences, use emitters with anti-negative pressure clogging function.