The Best Top-Dressing Periods for Wheat, Corn, Rice, Soybeans, Peanuts and Sorghum

China's main crops include wheat, corn, rice, soybeans, peanuts, sorghum, potatoes and foxtail millet, and top-dressing is the fertilizer applied during these crops' growing period; it should generally be carried out during the period of vigorous growth, when the fertilizer effect is best. So when are their best top-dressing periods? For details, see below.

1. Soybeans

Soybeans are a crop with a relatively high nitrogen requirement. Applying nitrogen fertilizer once at the early flowering stage can reduce the rate of flower and pod drop, extend the plant's lifespan, increase grain weight and raise the yield. Generally, apply 10-15 kg of ammonium nitrate or 10 kg of urea per 667 sq m.

2. Peanuts

About 15 days after the peanuts emerge, the flower buds begin to differentiate in large numbers and root nodules begin to form. When the plant produces two pairs of lateral branches, nitrogen fertilizer should be applied once in good time, with 10 kg of ammonium bicarbonate or 8 kg of urea per 667 sq m.

3. Potatoes

Top-dressing can generally be applied before the potatoes flower; for early-maturing varieties, top-dressing at the seedling stage is preferable, while for mid- and late-maturing varieties, top-dressing before budding is better, applying 13-15 kg of ammonium bicarbonate or 10 kg of urea per 667 sq m.

4. Foxtail millet

From the booting stage to the heading stage, apply 6 kg of urea in combination with irrigation or rainfall; at the heading and grain-filling stages, spray 150-250 g of potassium dihydrogen phosphate per 667 sq m.

5. Sorghum

Apply the first top-dressing at the jointing stage, with 10-15 kg of ammonium nitrate or 8-12 kg of urea per 667 sq m; then apply a second top-dressing at the booting stage, with 10 kg of ammonium bicarbonate or 5 kg of urea per 667 sq m.

6. Wheat

Wheat should be top-dressed at the 3-leaf stage, applying 13-18 kg of ammonium nitrate or 9-12 kg of urea once per 667 sq m; apply a foliar top-dressing once at the heading and flowering stage, spraying a mixed solution made from 120 g of potassium dihydrogen phosphate and 1.5 mg of undiluted 30-alkanol per 667 sq m mixed with 20 kg of water, or alternatively spray 160 g of potassium dihydrogen phosphate plus 1.5 kg of urea per 667 sq m mixed with 30 kg of water.

7. Corn

From after the jointing stage to the large trumpet stage, corn is at its peak of nutrient uptake. Apply the first top-dressing around the jointing stage, with 10 kg of ammonium nitrate or 7 kg of urea per 667 sq m; apply the second top-dressing 7-10 days before heading, with 20 kg of ammonium bicarbonate or 10 kg of urea per 667 sq m; if the base fertilizer is relatively sufficient and the soil is also very fertile, a single concentrated top-dressing can be applied, combined with deep application during intertillage and weeding.

8. Rice

Rice's absorption of nitrogen fertilizer begins to increase gradually after the green-turning stage, and only reaches its peak of fertilizer uptake at the peak tillering stage. In order to promote early and rapid growth of rice and early tillering, tillering fertilizer should be applied early and heavily. Apply 1.5 kg of ammonium nitrate per 667 sq m 7-10 days after transplanting, and apply 7 kg of urea after heading.