Red blight is a common physiological disease in rice. In recent years, the area of ​​straw returning and machine-inserted rice has increased. The disease is usually caused by deficiency of potassium, phosphorus deficiency and zinc deficiency, and poisoning caused by excessive soil reducing substances. The Yancheng area is mainly zinc deficiency and poisoning. Zinc deficiency is mainly caused by low effective zinc content in the soil, antagonism of phosphorus and zinc, and long-term water layer in rice. When the straw is returned to the field, the use of traditional water slurry management will aggravate the occurrence of red wilt.
After the occurrence of red bump disease in rice fields, the type should be judged according to the characteristics of the symptoms, and measures should be taken in a targeted manner. The lower leaf color of the phosphorus-deficient type turns dark green. There are significant differences between the symptoms of potassium deficiency and zinc deficiency. First, the starting point of the disease site is different. The symptoms of potassium deficiency are from the tip of the middle and lower leaves. The symptoms of zinc deficiency are symptoms of new leaves and middle and lower leaves. Second, the development is different. Potassium Symptoms The auburn spots develop along the leaf margin, and zinc-deficient symptoms develop along the midrib of the leaf, and the tip of the leaf curls. The symptoms of poisoning are mainly judged from the roots and the soil. When the seedlings are pulled, the soil is less soiled. After washing the soil, there are many black roots, and there are few or no new white roots. There is a smell in the roots. The soil is bubbling and there is a smell.
Phosphorus and potassium fertilizer should be added to the deficiency of phosphorus and potassium deficiency. For the zinc deficiency type, 0.2% to 0.3% zinc sulphate solution can be sprayed, or when only a thin layer of water is drained to the field, 1 kg of zinc sulphate and 5 to 10 kg of urea are applied per acre, and the water naturally falls to a new root length. When the leaves turn green, the roots turn white and then water. Poisonous red wilt disease is generally accompanied by zinc deficiency symptoms. It should be continued for 5 to 7 days on the basis of general application of zinc fertilizer to improve the soil environment and promote new roots.
The red wilt has a great impact on the growth of rice, and the following measures should be taken to prevent it in production.
The first is soil testing and formula fertilization. Zinc-deficient soil is mixed with 1 kg of zinc sulphate per mu and 15-20 kg of urea for the application of tillering fertilizer (transplanted rice is applied 5-7 days after planting, and direct seeding rice is applied at 4 leaf stage, zinc fertilizer is best not to Phosphate fertilizer is applied at the same time). Rational application of phosphate fertilizer according to soil available phosphorus content reduces the antagonistic effect of phosphorus and zinc.
The second is to strengthen the management of water slurry. Machine inserted rice and hand-planted rice shallow water transplanting, inch water live tree, transplanted for 3 to 4 days, then dry and ventilated for 1 to 2 days, the water is applied to the manure, and the field is dried for 1 to 2 days after each irrigation. The aerobic decomposition of soil organic matter and straw reduces the production of toxic reducing substances and promotes root growth. Rice did not form aerated tissue before the 3-leaf stage, and the oxygen required for root growth was provided by the soil. Therefore, the direct seed did not establish a water layer before the 3-leaf stage, and the water layer began to be established at the 4-leaf stage, but each time the water was filled, Leave it for 1 to 2 days and refill with fresh water.
Third, in the case of continuous rainy weather, the water layer in the field should be shallow. The water outlet in the rainy season should be flat. The water layer should not be kept too long. The water should be cut off once every 4 to 5 days. The rain should be drained in time after the rain. After ~3 days, change the river with higher temperature.
The fourth is to improve the quality of straw returning. Use the harvester with good quality of crushed straw to harvest the hoe before use, plough with large machinery, smash the field after watering, turn the straw into the soil, intermittent irrigation, promote the aerobic decomposition of straw, and reduce the production of reducing toxic substances.
The fifth is to promote the scorpion type planting and the scorpion type blanket scorpion. Using a carpet machine to insert the rice transplanter, the roots of the seedlings are large, the seedling period is long, the new roots appear slow, and the probability of red blight is high. The promotion of sputum-type planting and scorpion-type ruthenium-like sputum can make the root system planting small, slow seedling period, dry and dry in time, and the seedling grows strong and reduces the probability of occurrence of red rot.
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