How should topdressing be reasonable in the process of corn planting?

Big horn machine (about 10~ 12 pieces) is the most suitable period for corn in autumn rain. This is because the reproductive growth and nutritional growth of corn are relatively strong at this time, and the demand for fertilizer is also relatively large. During this period, topdressing can provide the supply needed for corn growth, promote ear differentiation, make corn ear produce many large particles, and the yield increase effect is obvious. Corn can be fertilized once or topdressing many times. If topdressing is repeated, topdressing twice is a good time-saving method.

Autumn rain is in booting stage. At this time, in order to meet the needs of corn growth, the amount of autumn rain should be moderately large. The second autumn rain will harvest the autumn ears of wheat and grain. When topdressing twice, the principle of fertilizer distribution is that the first topdressing can account for two thirds of the total amount, and the second topdressing can account for one third of the total amount. The first topdressing can be carried out around 9- 1 1 century. Many friends directly spread fertilizer and topdressing, but nitrogen fertilizer is the main topdressing for corn. If the soil surface is too shallow, a large amount of fertilizer will be lost, and the effect of topdressing is not good. Therefore, it is best to cover the soil and apply it deeply when topdressing, and avoid applying chemical fertilizer along shallow cities, open markets and water. When topdressing, it is necessary to look at the land, Miao Yuqiu, lowland and saline-alkali land, and topdressing with acidic or physiologically acidic fertilizers such as ammonium nitrate, ammonium sulfate and calcium superphosphate. Non-volatile ammonium nitrate or urea should be used as topdressing for conservative soil with poor fertilizer conservation ability. Planting density is much higher, and low density is not suitable. Weak seedlings should be topdressing as soon as possible, and foliar fertilizer can be sprayed separately if necessary.

Topdressing at seedling stage should not be too early. Topdressing before weeding often leads to the growth of maize and the weakening of root system. Excessive topdressing at grain filling stage will make corn late. In addition, when supplementing rainfall, we should pay attention to the weather conditions to avoid the impact of bad weather. The whole growth period is basically stable, generally reaching the highest point at the male silking stage, and gradually decreasing from filling to maturity, but corn is absorbing nitrogen throughout the growth period. Insufficient nitrogen will make the leaves of plants yellow, slow growth, short plants and yellow lower leaves.

Corn is also absorbed throughout the growing period. Like nitrogen fertilizer, the male selection stage reached its peak and then declined, but the later purchase amount was about one third. When phosphorus is insufficient, the leaves turn yellow, brown spots appear and dead leaves appear. From the promotion node to the booting stage, it gradually rises, and the flowering stage is the highest, and it will not be absorbed in the future, but the potassium in plants is often reduced due to external infiltration. If potassium is insufficient, the leaf center and new leaves will appear yellow-green, the leaf tip and leaf edge will turn yellow, and even appear necrosis, and there is an obvious dividing line, which makes the leaves bend.