How to apply topdressing after wheat turns green? Analysis of the latest three-point observation key points

As temperatures rise, wheat will enter a stage of rapid growth and development, and the key period for topdressing wheat after it turns green will also arrive. Most farmers arbitrarily increase the amount of green-turning fertilizer when topdressing, causing wheat lodging and reduced yields. Therefore, the author suggests that farmers apply topdressing to wheat after it turns green according to the “three observations” to ensure a bumper wheat harvest this year.

First, fertilize according to seedling condition. During topdressing, apply fertilizer by classification according to different seedling conditions. Generally speaking, late-sown seedlings and weak seedlings should be heavily fertilized to increase the tillering and ear-forming rate; strong seedlings should receive little or no green-turning fertilizer. At the same time, for wheat fields that did not form strong seedlings in winter or have few tillers per plant, with a total stem and tiller number per mu below 400,000, early and heavy application is required, generally applying 20 kg per mu of a three-element sulfur-based compound fertilizer. For strong seedlings with good individual development and a moderate population during the overwintering period, apply little or no fertilizer, mainly controlling the jointing fertilizer to reduce the breeding of ineffective tillers in spring, prevent row and ridge closure, and facilitate ventilation and light penetration. For overly large populations of excessively vigorous seedlings, in addition to controlling fertilizer and water at the green-turning stage, measures such as deep tillage and chemical regulation should also be taken to control the growth of wheat roots, stems, and leaves.

Second, fertilize according to soil. Sandy soil, because it “supports young seedlings but not old seedlings” and has poor fertilizer and water retention capacity, should be appropriately fertilized more; if fertilization is insufficient, it will have a certain impact on the number of ears and grains as well as later growth. Clay soil, because fertilizer efficiency is poor in the early stage, should be fertilized less at the green-turning stage, and foliar fertilization can be adopted at the booting stage. Note that too much fertilizer should not be applied, to prevent excessive vegetative growth and lodging.

Third, fertilize according to weather. If rain occurs during the green-turning stage, use a fertilizer applicator to apply chemical fertilizer; broadcasting chemical fertilizer is strictly prohibited to avoid burning seedlings and leaves and affecting wheat growth. Broadcasting chemical fertilizer not only prevents wheat from absorbing it well, but also causes fertilizer volatilization and loss, resulting in unnecessary waste. In dry weather, irrigate promptly after fertilization to improve fertilizer use efficiency.