When is the best time for topdressing crops?

When is the best time for topdressing crops? Please give guidance to topdressing crops can refer to the following list: 1. Corn is the peak period of nutrition absorption from jointing to trumpet mouth stage. generally, the first fertilizer can be applied before and after jointing, 150 kg ammonium nitrate or 120 kg urea per hectare; 7-10 days before heading, the second fertilizer should be applied again 225 kg ammonium nitrate or 180 kg urea per hectare. If the base fertilizer and seed fertilizer are sufficient, and the soil is very fertile, you can concentrate on topdressing once and fertilize deeply in combination with the second shovel. Three days before heading, foliar spraying corn Zhuangfengling will get higher yield. 2. In order to meet the nutrient needs of sorghum from jointing to heading, sorghum should apply the first fertilizer at jointing stage, 150 kg of ammonium nitrate per hectare or 120 kg of urea per hectare, and the second fertilizer at the flag stage of booting. 120 kg ammonium nitrate or 75 kg urea per hectare. 3. The absorption of nitrogen fertilizer by rice increased gradually from turning green, and reached the peak at the peak tillering stage. In order to promote the early emergence and tillering of rice, tillering fertilizer should be applied and re-applied early. Generally, 225 kg of ammonium sulfate per hectare can be applied 7 to 10 days after transplanting, and 100 kg of urea can be applied at heading. 4. Wheat should be fertilized at the three-leaf stage, generally applying ammonium nitrate 195 kg 270 kg or urea 135 kg 180 kg per hectare. In the later stage of wheat, due to the weakening of the ability of root system to absorb nutrients from soil, one extra-root topdressing should be carried out at heading and flowering stage. 2250 grams of potassium dihydrogen phosphate, 22.5ml of triacontanol solution and 300kg of water per hectare can be sprayed, or 3000 grams of potassium dihydrogen phosphate per hectare, 15kg urea and 450kg water can be sprayed. 5. Soybean is a crop that needs more nitrogen fertilizer. Nitrogen fertilizer is usually applied once at the early flowering stage of soybean, which can reduce the rate of falling flowers and pods, prolong plant life, increase grain weight and improve quality. Generally, 150 kg ammonium nitrate or 120 kg urea can be applied per hectare, and one extra-root topdressing can be carried out at the podding stage of soybean, and the effect of increasing yield is more obvious. 6. Sunflower planting sunflower should not only apply sufficient base fertilizer, but also top dressing. Generally, topdressing is carried out at the budding stage, with 225 kg of ammonium nitrate or 180 kg of urea per hectare. Farmers with conditions can also carry out extra-root topdressing at the flowering stage. 7. After setting the seedlings, the beet quickly turned to the luxuriant growth stage. In the early growth stage of the beet, combined with the second shovel, 150 kg of ammonium nitrate or 120 kg of urea was applied per hectare. 8. Generally speaking, potato can be topdressing before flowering stage, early-maturing varieties should be topdressing at seedling stage, and mid-late-maturing varieties should be topdressing before budding, applying 225 kg of ammonium nitrate or 150 kg of urea per hectare. Click to get more compound fertilizer application techniques