Rational Application of potassium Fertilizer to promote High yield of Spring Maize

With the improvement of maize yield, the supply of soil available potassium is required to increase in the key growth period. The results of many long-term positioning experiments of corn show that when the yield increases by 10% to 20%, the potassium uptake increases accordingly. The stable high yield can be maintained by properly increasing the potassium content of maize tissue. In the northern spring sowing corn area, although the content of soil available potassium is at a high level (such as 70mg / kg, 130mg / kg), the application of potassium fertilizer can still increase the yield. Especially for some soils with medium content of available potassium and small capacity of slowly available potassium, it is necessary to consider the application of potassium fertilizer in high-yield fields. Therefore, when taking the yield target as the main basis for recommending potassium application, paying attention to the application of potassium fertilizer to the soil with low available potassium content is a necessary measure to ensure high yield. It should also be noted that the application of appropriate amount of potassium fertilizer has a good effect even when the level of available potassium in some soil is medium. Effect of increasing planting density on potassium requirement. At present, in the high-yield cultivation of hybrid maize, the yield is often greatly increased by increasing density, and at the same time, the potassium uptake of high-density plants to farmland is also significantly increased. Therefore, when the density increases, if there is no corresponding application of potassium fertilizer or improve the effectiveness of soil potassium, it is difficult for crops to absorb potassium, and the yield may decrease or fail to reach the ideal level. However, after the application of 5kg / mu of potassium fertilizer, the yield increased rather than decreased, especially in the corn plots with low available potassium content and irrigation conditions. Therefore, in the recommended fertilization of corn, in order to adapt to the higher density and yield level, the amount of potassium application should be appropriately increased than the conventional amount. It is very important to coordinate the balanced supply of potash fertilizer and nitrogen fertilizer in the cultivation of dense planting high-yield maize. In general, more nitrogen is applied in order to achieve the goal of high yield, which increases the infection rate of plants to diseases and insect pests such as stem rot, root rot, bacterial wilt and so on. If the supply of potash fertilizer is not increased accordingly, symptoms of nitrogen and potassium imbalance will be formed. Potassium deficiency first weakened the bending strength and epidermis thickness of maize stems and leaves, which not only increased the possibility of lodging, but also increased the sensitivity of maize to insect pests and diseases. As we all know, among the nutrient elements, nitrogen and potassium have great effects on the disease resistance of maize, but their action directions are different. Too much nitrogen will often increase the sensitivity of maize to disease, while the effect of potassium is the opposite, which can increase the disease resistance of crops. Diagnosis of potassium deficiency in the field and remedial measures of topdressing: spring corn has entered the jointing stage, and the growth period from small trumpet mouth to big trumpet mouth is its rapid growth period, and the demand for nitrogen, phosphorus and potassium elements has increased. It is usually used to apply only nitrogen fertilizer but not potassium fertilizer in actual production. However, in the high-yield and close-planting cultivation of spring maize, whether topdressing is needed or not can be answered by observing the growth status of the plant. That is to often go to the corn field at 90 o'clock in the morning, especially in windy weather. If you see the leaves of spring corn wilting in the morning, it is lack of potassium. Because for the farmland that is not in urgent need of irrigation, normal and robust corn plants will not wilt leaves in the morning, but it is normal to wilt after noon. Because potassium can affect the stomatal closure of leaves and increase the water retention function of plants. When potassium is deficient, the stomatal resistance is large and can not be closed normally, which leads to serious water loss in maize and wilting phenomenon. At this time, potash fertilizer must be applied to remedy it. The most feasible measure is to topdressing potassium chloride 5kg / mu and covering soil after ditch application or hole application.