First, the morphological characteristics. In the early stage, the upper leaves were dark green, sometimes brown spots appeared. Then the old leaves of the base showed the earliest symptoms, the tip of the leaves turned yellow, and there was a tendency of the leaves from the tip of the leaves to be inlaid with the dew, and then the black leaves died, and then the yellow leaves symptoms. Gradually spread to the adjacent leaves and gradually turn to the heart. The growth of rice plants is stagnant, the plants are short, and the tillers become smaller. Root growth is poor, yellowish brown to dark brown. It has been observed that indica rice has a pre-existing spot on the tip of the leaf, and there is an early symptom of the leaf tip fading and yellowing, while the japonica rice is not obvious.
Second, the cause of the disease 1, the lack of direct use of potassium in the soil. The soils that are prone to potassium deficiency are: shallow soil fields and water-soil fields, deep paddy fields, poorly ventilated, and slow-growing potassium fields.
2. The fertilizer composition is not balanced. Potassium deficiency due to partial application of nitrogen and phosphate fertilizer has been common in many places and has seriously affected the increase of rice yield.
3. Soil pH is not appropriate. The effective potassium in the soil is the highest when the soil pH is around 7. When the soil is acidic, the amount of potassium in the soil increases. It leads to a decrease in the effective potassium content in the soil and is prone to potassium deficiency. Potassium deficiency in rice is sometimes caused by the low temperature of soil in the soil and low temperature, and it is also caused by the presence of a large amount of reducing substances in the soil.
Third, preventive measures. According to the degree of potassium deficiency, combined with the fertilization level of nitrogen and phosphorus, the appropriate amount of potassium fertilizer is used. The potassium-deficient soil is added with potassium chloride, potassium sulfate, potassium magnesium fertilizer or grass ash in the form of base fertilizer to ensure that the potassium-nitrogen ratio in the tillering period is above 0.5.
Improve the soil, deepen the tillage layer, and increase the guest soil. The application of manure and soil fertilizers promotes the formation of soil aggregate structure. The winter leisure field is used for winter ploughing, promoting soil ice-melting and weathering, and exerting the potential fertility of the soil.
Paddy fields that have been deficient in potassium should be drained immediately, placed on the field, or dried and wet, so that they are ventilated. At the same time as the application of nitrogen fertilizer, combined with the use of potassium fertilizer, can also be sprayed with 0.2% potassium dihydrogen phosphate 2-3 times.
Add organic fertilizers, promote straw returning, and grow green manure in conditions where conditions can improve the soil environment.
Second, the cause of the disease 1, the lack of direct use of potassium in the soil. The soils that are prone to potassium deficiency are: shallow soil fields and water-soil fields, deep paddy fields, poorly ventilated, and slow-growing potassium fields.
2. The fertilizer composition is not balanced. Potassium deficiency due to partial application of nitrogen and phosphate fertilizer has been common in many places and has seriously affected the increase of rice yield.
3. Soil pH is not appropriate. The effective potassium in the soil is the highest when the soil pH is around 7. When the soil is acidic, the amount of potassium in the soil increases. It leads to a decrease in the effective potassium content in the soil and is prone to potassium deficiency. Potassium deficiency in rice is sometimes caused by the low temperature of soil in the soil and low temperature, and it is also caused by the presence of a large amount of reducing substances in the soil.
Third, preventive measures. According to the degree of potassium deficiency, combined with the fertilization level of nitrogen and phosphorus, the appropriate amount of potassium fertilizer is used. The potassium-deficient soil is added with potassium chloride, potassium sulfate, potassium magnesium fertilizer or grass ash in the form of base fertilizer to ensure that the potassium-nitrogen ratio in the tillering period is above 0.5.
Improve the soil, deepen the tillage layer, and increase the guest soil. The application of manure and soil fertilizers promotes the formation of soil aggregate structure. The winter leisure field is used for winter ploughing, promoting soil ice-melting and weathering, and exerting the potential fertility of the soil.
Paddy fields that have been deficient in potassium should be drained immediately, placed on the field, or dried and wet, so that they are ventilated. At the same time as the application of nitrogen fertilizer, combined with the use of potassium fertilizer, can also be sprayed with 0.2% potassium dihydrogen phosphate 2-3 times.
Add organic fertilizers, promote straw returning, and grow green manure in conditions where conditions can improve the soil environment.
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