Talk about several irrigation methods of vegetables: vegetable varieties, cultivation methods and cultivation period are different, the climate conditions are different, must use a variety of irrigation methods to meet the requirements.
1. Surface irrigation
It is suitable for the soil and lot with sufficient water source, smooth land, thick soil layer and smooth drainage of soil bottom. Its advantages are low investment, easy to implement, suitable for large area vegetable production, but the cost of labor and water, easy to make the soil surface compaction. Surface irrigation can be divided into border irrigation, furrow irrigation and inundation irrigation.
(1) border irrigation
Suitable for planting dense or need frequent irrigation vegetables (such as green leaf, cucumber, etc.). Furrow surface should be smooth, furrow layout should be reasonable, and flow into furrow and water discharge time should be controlled. The size of the beds, the flow into the beds and the length of drainage time are related to soil permeability, land flatness and ground slope. The soil permeability is strong, the land is not smooth or the slope of the ground is small, it is suitable to use short bed irrigation with large flow; On the contrary, long furrow small flow irrigation can be used.
(2) ditch irrigation
It is suitable for most cultivated crops. In furrow irrigation, the moist range of cohesive soil is larger than that of sandy soil, but shallower. In order to make irrigation even, the distance, length, flow into furrow and discharge time of irrigation ditch should be reasonably determined according to the ground slope, soil texture and land smoothness of irrigation lot (with border irrigation). The general ditch length is 30 ~ 100 meters, and the flow rate into the ditch is 0.5 ~ 3.0 L/s. In the areas with poor soil permeability and large ground slope, the drainage flow should be reduced (0.1 ~ 0.2 L/s), and "trickle irrigation" or "long ridge and short irrigation" method should be adopted to ensure a large amount of water seepage in the ditch. Irrigation ditch is generally arranged along the slope of the ground, ditch distance should be determined according to the vegetable row distance, sand ditch distance should be smaller than clay.
According to modern requirements, the ground irrigation method should be set up underground water conveyance system, which can save land and prevent water leakage. A fixed gate is set in the land requiring irrigation to control the amount of water.
2. Underground irrigation
Water is introduced into the soil layer where vegetable roots are distributed by underground pipes, and the soil is wetted from the bottom up or around by capillary action. This irrigation method has the advantages of uniform soil moisture, no damage to the soil aggregate structure, no plate layer, less ground evaporation, water saving, high irrigation efficiency, can be carried out at the same time other operations, low air humidity near the ground, can effectively control disease and so on.
Although the fixed underground irrigation facility engineering quantity is larger, one-time investment is more, but has the above many advantages, it is a more promising irrigation method. The buried depth of fixed underground irrigation pipe should be below the winter soil layer and within the effective range of soil capillary. The non-fixed underground irrigation pipe is temporarily buried in the soil preparation, and the depth is controlled in the middle of the distribution layer of the main root groups of vegetables.
3. Above-ground irrigation
There are mainly two kinds of sprinkler irrigation and drip irrigation.
(1) Spray irrigation
The use of special equipment to pressurized water jet into the air and scattered into water drops fall, commonly known as "artificial rainfall", widely used around the world. Main advantages: (1) Water saving, 20 ~ 30% water saving than border irrigation and furrow irrigation. (2) Improve the field microclimate, adjust soil water, fertilizer, gas, heat conditions, do not damage the soil aggregate structure, can wash off the stem and leaf dust, is conducive to light energy utilization, yield increase effect is obvious. Labor saving, high irrigation efficiency, easy to realize automation. But the equipment investment is large, consumption power.
(2) Drip irrigation
Using a low pressure pipe system to drip water or a solution containing chemical fertilizer evenly and slowly into the soil near the roots of vegetables, the main advantages are:
① Save water, can completely avoid water delivery loss and deep leakage loss. Especially in hot and dry seasons and areas with strong water permeability, the water saving effect is particularly significant.
② Save labor, adapt to various terrain conditions, easy to realize automatic control of irrigation.
(3) Save land and fertilizer, the dry and branch pipes of the irrigation system are buried in the ground, saving the area of the channel, and can be combined with irrigation water to fertilize, avoid fertilizer loss and improve fertilizer efficiency.
(4) It can avoid the decrease of ground temperature caused by irrigation when used in protected areas in cold season.
(5) Drip irrigation can keep the soil in the optimal moist state and promote the high yield of vegetables. In order to prevent the drip plug of drip irrigation, reliable water filtration equipment must be available. The investment of drip irrigation equipment is high, and it is generally used in the protected land or the vegetables with high economic value that need to be cultivated.