According to the requirements of crop water demand, artificially to the farmland to replenish water and other measures of farmland. Irrigation can meet the demand for water for crops in time, improve soil water, fertilizer, gas, heat and salt, improve the microclimate of farmland, and achieve the goal of increasing agricultural production.
China is one of the earliest countries in the world to develop farmland irrigation. Qin and Han before the irrigation of farmland is called “immersion”, to the Han Dynasty has the name of “over- " or “irrigation”, the West Han time “irrigation” and “irrigation”, “irrigation” and use. After Tang used to use the word “irrigation”, and continue to use it to this day.
Irrigation PrincipleS Crops require a lot of moisture from seed germination to plant maturation. Crop water demand includes both physiological water and ecological water demand. Crop physiological water demand refers to the water required for various physiological activities (such as steaming, photosynthesis, etc.) in the course of crop life, and the water needed for the development and development of crops in the process of fertility. The former is represented by leaf steaming, which accounts for about 60 to 80% of the amount of water needed for crops, while the latter is represented by evaporation between plants, which represents about 20 to 40% of the amount of water needed for crops. If the amount of water absorbed by the plant is less than the amount of water consumed, i.e. when the water balance in the plant is out of balance, light causes temporary wilting and heavy dry death. Atmospheric drought or soil drought will cause the crop stems and leaves to suffer in varying degrees of wilting, resulting in the weakening of photosynthesis, affecting the production and accumulation of organic matter, while the root system water absorption function is weak, the body organic nutrient transport is destroyed. Water scarcity is more harmful to young crops and organs.