In the water-depleted areas, drought is the main obstacle to rice production. Even though the rainfall in the middle and lower reaches of the Yangtze River in the main rice producing areas and the Pearl River basin is relatively large, due to uneven spatial and temporal distribution of rainfall during the period of early and late rice growth, drought Still frequent. The most frequent of these is summer and autumn drought, affecting the early rice grouting and late rice growth. Therefore, the promotion of drought-tolerant rice varieties, the use of water-saving irrigation techniques, and the improvement of water resource utilization are important measures to ensure the continued stable, high yield of grain. Drought-reducing cultivation techniques For rice areas that are not irrigated or have poor irrigation techniques and are prone to summer or autumn drought, the strategy of shortening the growth period of rice, reducing the water requirement of rice, and completing grain evacuation before the formation of drought should be adopted. Select early rice varieties (combinations) with short growth period (about 110 days) and strong drought resistance. Use small sheds in small sheds to raise larvae and try to insert early sowing, and appropriately increase the density of planting. Reapply phosphorus and potash fertilizers to promote early growth of seedlings. Make full use of the natural rainfall in spring and summer. In the seedling stage, the depth of rice paddy is 5 to 10 cm. After the tillering stage, the depth of rice paddy is more than 10 cm, ensuring that the whole growth period is completed before the drought forms. Water-saving and drought-resistant cultivation In the double-season rice planting area, we must first use the rainfall in the spring and summer rainy seasons to allocate the entire amount of water in accordance with the spatial and temporal distribution of rainfall during the spring, summer and autumn seasons. We must adhere to the principle of “early storage and late irrigation and water-saving irrigation. The principle of water conservation, on the basis of fully improving the utilization rate of water resources, combined with water conservation, drought and disaster reduction cultivation techniques, so as to raise the overall drought tolerance level of rice production. During the growth of early rice, full use of natural rainfall, the use of deep water storage, shallow irrigation irrigation method (ie, seedling Datian water storage 10 cm, 15 cm water storage in the middle and late period, the field is not open hair, no irrigation, each irrigation depth is not More than 3 cm), strive to use less or less reservoir water resources in early rice. During maturing and harvesting of early rice, undrained and unseasoned fields were used, and late rice was transplanted with no-tillage and intermittent irrigation. Under the premise of not affecting the yield of rice, the amount of irrigation water is reduced as much as possible, the utilization rate of water resources is increased, and the ability to store water and resist drought is enhanced. The water-retaining technology will increase organic fertilizers, phosphorus and potash fertilizers, and increase the water retention capacity of soil and plants. Straw in the field to reduce the evaporation of water. In regions where water is extremely scarce, polymer water retention agents (eg, macromolecular water-absorbing resins made from starch and acrylonitrile) can be used to improve soil water retention. Covering cultivation with plastic film reduces moisture loss. The disaster reduction technology sprays 0.2% to 0.5% of potassium dihydrogen phosphate solution before the beginning of drought to increase plant water holding capacity. When the effective water content in the soil is reduced and the plants begin to turn leafy, spraying transpiration reducing agents (such as dryland dragons with fulvic acid as the main component) will reduce water loss and improve drought tolerance. When a long drought causes the upper leaves to die, the leaves are cut off and covered with rice. After the drought is lifted, if the rice stem stalk is still green, a top dressing is added to promote the growth of axillary buds and the formation of ratoon rice.
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