After the emergence of soybeans, generally when the soybean buds are in a compound leaf, 3 to 5 kg of urea can be used for topdressing per acre. The green food soybeans are not chased by chemical fertilizers, but the organic fertilizers are used, and the high-quality agricultural fertilizers are 500 kg. If the seedling grows strong and there is no shortage of fertilizer, the seedling stage may not be applied with nitrogen fertilizer or less nitrogen fertilizer, so as to avoid plant growth.
Flowering and pod-forming period is the critical period of fertilizer requirement, and it is also the most vigorous period of soybean growth and development. Applying an appropriate amount of nitrogen fertilizer 5 to 7 days before flowering or early flowering can promote the formation of carbohydrates and proteins, and also reduce flowers. The pods fall off, promote early maturity, increase yield, and have obvious effects. Tests show that in this period, the application of nitrogen fertilizer increased by more than 10% compared with the general mu without nitrogen fertilizer. Generally, 200-250 kg of ammonium nitrate is applied per hectare, or 130-160 kg of urea is combined with cultivating soil for topdressing.
When soybean enters the pod-forming period, the root activity declines, the nitrogen-fixing capacity of Rhizobium gradually decreases, and the ability to absorb fertilizer decreases. The amount of nitrogen and phosphorus absorbed by soybean in the grain-filling period accounts for 60% and 65% of the total growth period, respectively. The top dressing is applied by top dressing, that is, the method of foliar spraying to increase the maturity of soybeans, increase the weight of 100 grains, and improve the quality of soybeans. The application of nitrogen fertilizer in the blast stage and the end of the pod can not only meet the needs of soybean granules, but also cause the plants to grow, so it can greatly increase grain yield.
Soybean topdressing must seize three periods
Soybeans require more than three major factors: nitrogen, phosphorus and potassium. In particular, soybeans are rich in protein and require more nitrogen. Since soybean rhizobium can fix nitrogen in the air, soy application of nitrogen fertilizer is often overlooked. In fact, the fixed nitrogen of Rhizobium can only meet 1/3 to 1/4 of the nitrogen requirement of soybean. Therefore, it is necessary to apply 60% to 70% of nitrogen nutrition from the soil to grow soybeans. Soybean should not be applied to the base fertilizer. If the base fertilizer is applied excessively, it will seriously affect the emergence of roots. The seed fertilizer will cause serious damage to the radicle and hypocotyl of soybean, and even cause some seeds to not germinate. Therefore, the top dressing of soybean is especially important. According to the law of soybean growth and development, soybean topdressing mainly captures three periods, one is the seedling stage, the other is the flowering and pod-forming stage, and the third is the drumming stage.
ã€Comment】 ã€Print this article】 ã€Close this page】 ã€Large, medium and small】