In the recent period, the authors have observed the symptoms of potassium deficiency in crops such as cotton, rice, corn, soybeans, and peanuts in several provinces in the middle and lower reaches of the Yangtze River. In addition to the partial lack of potassium in the soil, the authors have, to a large extent, grown crops this year. During the period of heavy rainfall more potassium loss related.
From the cotton point of view, most cotton fields have potassium deficiency phenomenon, the lower part of the cotton leaves appear yellow and white piebald early, and then the edges of the leaves are reddish with brown spots, and severe leaf margins begin to scorch. Potassium-deficit rice leaves have auburn spots on the old leaves, and the leaf margins are coked. The stems are easy to fall down or even broken. The potassium deficiency in young leaves of yellow maize plants is short and the old leaves are brown and brown. The old leaves of soybean lack potassium. The edges of the old leaves are yellow, and some are curled downwards. The middle part of the leaves remains green. Peanuts lack potassium leaf color light green, the edge of the leaves coke. The common characteristic of potassium deficiency in these crops is that the tips of the lower leaves turn yellow and gradually yellow along the edges of the leaves, but remain green on both sides of the veins and in the middle of the leaves. Most of the leaves with severe potassium deficiency have yellow or scorching edges.
Potassium fertilizer has many functions in the growth and development of crops. First, it can increase the turgor pressure of the crop cells, make the cells rich in elasticity, and can control the opening or closing of stomata in the leaf cells, which helps the crops absorb more carbon dioxide and create carbon and water. Compounds to form sugars and starches; second, to promote root development, absorb more water, reduce water evaporation, and accordingly increase crop drought resistance; third, potassium is mainly found in stems and leaves, and can promote stalk cellulose. Develop, improve the support ability of stalk, enhance the ability to resist lodging and resist pests and diseases; Fourth, potassium plays an important role in the transformation and transportation of nutrients in crops, and can accelerate the absorption and utilization of other nutrient elements; Fifth, it can significantly To increase the yield of crops, such as the application of potash fertilizer to insect-resistant cotton, can greatly increase the yield and improve the quality of crops.
In view of the widespread shortage of potassium in crops this year, it is imperative that potassium be applied in a timely manner.
First of all, to distinguish between different soils applied potassium fertilizer. Potassium fertilizer applied to the soil can generally increase production, but the yield increase rate of different soils is different. After potash fertilizers are applied to soil, viscous soils can absorb more potassium and lose less, while sandy soils have poor adsorption capacity and readily available potassium is lost. Therefore, a little potassium fertilizer can be added to sticky soil at one time, and potassium can be applied to sandy soil. The increase in production is significant, but it should be applied in divided doses.
Second, it should be applied according to different crop types. The compatibility of crops with potassium fertilizers is better, but due to the fact that the components of potash fertilizers are not completely the same, some components have inhibitory effects on the growth and development of some crops, such as tobacco, potatoes, watermelons, and tea, which are very sensitive to chloride ions. The application of potassium chloride will reduce the yield of these crops and deteriorate their quality. If these crops are topdressed with potassium sulfate, both increase production and increase efficiency. However, potassium chloride has good effects on cotton, rice, corn, soybeans and other crops.
Third, pay attention to application techniques. Faced with the current situation of more potassium loss in the rainy season this year, potassium fertilizers must be rapidly applied to potassium-deficient crops. The first is that crops with larger row spacing and longer growth period can be used to open up the trenches or chase the potassium sulfate at the rows, about 10 kilograms per mu; second, 0.2%~0.3% phosphoric acid is sprayed on the roots. Dihydrogen potassium or 1% potassium sulfate solution, or a mixture of 1% urea and 1% potassium sulfate; Third, starting from the actual situation in various markets, matching the local application of effective, high-content foliar spray potassium.