When is the best time to fertilize corn

The best time for corn topdressing is from the jointing stage to the large bell mouth stage, during which fertilization helps promote the enlargement of the corn cob. The effect of topdressing is mainly influenced by factors such as soil fertility, variety characteristics, climatic conditions, field management, and fertilizer types.

1. Topdressing during the tillering stage

The tillering stage of maize is a critical stage for rapid stem elongation, during which topdressing with nitrogen fertilizer can promote robust plant growth. Urea combined with potassium fertilizer can be applied per acre to supplement nutrients and enhance lodging resistance. When the soil moisture is insufficient, irrigation should be combined to avoid fertilizer burning the roots.

2. Fertilization during the Large Horn Stage

The large horn stage is the peak period of maize fertilizer demand, during which ear differentiation is completed and grain formation is entered. Applying high nitrogen and high potassium compound fertilizer can significantly increase the number of grains per ear and thousand grain weight. Timely tillage and soil cultivation after fertilization can improve fertilizer utilization efficiency. Sandy soil needs to be applied in small amounts in stages to prevent erosion.

3. Soil fertility regulation

Poor land should increase the frequency of topdressing on the basis of base fertilizer, and supplement twice during the jointing and tasseling stages. Fertile land can reduce the amount of topdressing and prevent plants from being too green and late maturing. When fertilizing acidic soil with lime, it can improve nutrient absorption efficiency.

4. Variety characteristics adaptation

Compact varieties are resistant to dense planting, and the fertilization time can be appropriately advanced to the small horn stage. Flat type varieties need to control the amount of topdressing during the jointing stage to prevent excessive leaf growth. Late maturing varieties can be supplemented with ear fertilizer before and after tasseling to extend the grain filling period.

5. Climate condition matching

Top dressing in dry years should be combined with precipitation or irrigation, and in rainy seasons should avoid before and after rainstorm. In low temperature years, increasing the application of phosphorus and potassium fertilizers appropriately can improve cold resistance. In high temperature seasons, topdressing should be carried out in the evening to reduce evaporation losses.

Corn topdressing should be flexibly adjusted according to the growth of the field. For thick green leaves, topdressing can be postponed, and for yellow leaves, it should be supplemented in advance. Regularly observe the growth of plants after fertilization, and improve fertilizer efficiency by combining tillage and weeding. Pay attention to balancing the ratio of nitrogen, phosphorus, and potassium to avoid excessive growth caused by biased application of nitrogen fertilizer. It is recommended to use a small amount of multiple topdressing methods for sandy loam soil, and concentrated deep fertilization can be applied for clayey soil. Under special climatic conditions, it is necessary to consult agricultural technicians to develop personalized fertilization plans.