When Is the Best Time to Fertilize Wheat? A Detailed Guide to Key Fertilization Techniques

Wheat is the collective name for plants of the wheat genus, a grass family plant widely cultivated around the world, and the caryopsis of wheat is one of humanity's staple foods.So when is the best time to fertilize wheat? What are the key fertilization techniques?

When is the best time to fertilize wheat?

1. Topdressing for winter wheat is generally based on nitrogen fertilizer, and the topdressing time is mostly from the greening stage to the jointing stage in the following spring. After wheat turns green, it enters a period centered on the growth of roots, leaves and tillers. The yield level of winter wheat that year is very sensitive to the response of nitrogen nutrient supply during this period, which is also called the critical period of nitrogen nutrition.

2. Spring wheat: (1) Seed fertilizer: Because the fertilizer is concentrated near the seeds, wheat can use it once it sprouts and grows roots. The specific method is to level the land and make beds before sowing, open furrows according to the predetermined row spacing, then spread fertilizer, sow seeds, cover with soil and compact in the furrows. If the soil is dry, you can sow and firm the soil first, then spread fertilizer, cover with soil and compact. Generally, 150 kg of ammonium bicarbonate and 225-375 kg of superphosphate per hectare are applied mixed with 1500 kg of high-quality farmyard manure, or 150-300 kg of binary nitrogen-phosphorus compound fertilizer. In recent years, spring wheat producing areas have used a one-time fertilization method, with all fertilizer used as base fertilizer and seed fertilizer. Generally, on the basis of applying sufficient farmyard manure, 600-750 kg of ammonia water or about 600 kg of ammonium bicarbonate per hectare, and 750 kg of superphosphate. When sowing, combined with a small amount of seed fertilizer, 75-120 kg of diammonium phosphate per hectare, and no topdressing afterward. This method is suitable for dry land.

(2) Topdressing: Spring wheat is a crop that is “rich from the start”, developing early. Most varieties begin elongation of the growth cone and differentiation of the rachis at the 3-leaf stage. Young spike differentiation begins at the 4-leaf stage, requiring more nutrients. Therefore, the first topdressing should be carried out at the 3-leaf stage or when there are 3 leaves and 1 heart. This fertilization is called tillering fertilizer and should be applied heavily, accounting for about 2/3 of the topdressing amount. Apply 225-300 kg of urea per hectare, mainly to increase the rate of tillers forming spikes, promote strong seedlings to develop early, and lay the foundation for large spikes and many grains. The second topdressing carried out at the jointing stage is called jointing fertilizer, generally applied lightly, accounting for about 1/3 of the topdressing amount, with 105-150 kg of urea per hectare. In plots that have not been topdressed with tillering fertilizer, the jointing fertilizer should be applied early and heavily. At the booting stage, apply an appropriate amount of fertilizer to preserve flowers and increase grains. After most of the jointing fertilizer has been applied, no more fertilizer is applied, and foliar fertilization is mainly carried out, the same as for winter wheat.

What are the key techniques for wheat fertilization?

The normal growth and development of wheat requires various elements such as nitrogen, phosphorus, potassium, iron, zinc, copper and manganese. Among the three major elements of nitrogen, phosphorus and potassium, it requires relatively more nitrogen and potassium and less phosphorus. According to research data, for every 100 kg of grains formed, wheat needs to absorb 2.8 kg of pure nitrogen, 1 kg of phosphorus pentoxide and 2.4 kg of potassium oxide, and the fertilizer requirement increases with the increase in yield level. Generally, a wheat field needs 12-15 kg of pure nitrogen and 6-8 kg of phosphorus pentoxide throughout the whole growth period, combined with 5-6 kg of potassium fertilizer (potassium oxide). Elements such as zinc, boron and manganese should be applied according to the soil nutrient supply status, supplementing what is deficient and using them in a targeted manner. In terms of application by stages, follow the principle of “heavy application of base fertilizer, skillful application of topdressing” and adjust reasonably.

1. Base fertilizer

“Wheat likes to be rich from the start, and base fertilizer is the foundation.” Before land preparation, generally apply 1-1.5 tons of farmyard manure per mu, and at the same time apply 30-50% of the nitrogen fertilizer, all of the phosphorus fertilizer and 20% of the potassium fertilizer as base fertilizer. It is recommended to apply 3 kg of zinc fertilizer and 2 kg of boron fertilizer. When applying, it is best to evenly spread them on the surface before plowing and promptly plow them into the soil.

2. Topdressing

Topdressing is generally carried out at the jointing stage, mainly with nitrogen fertilizer. The amount of nitrogen topdressing accounts for 50-70% of the total application. If wheat has many tillers, good seedling conditions and vigorous growth, it can be applied appropriately later and the application amount reduced. Topdress twice at the booting stage. If the base application of phosphorus and potassium fertilizer is insufficient, it should also be supplemented through topdressing, but phosphorus and potassium topdressing should be advanced as much as possible to the tillering stage, and compound fertilizer is best. Water promptly after topdressing, with about 40 m3 of water, and do not flood irrigate.

Foliar spraying is also a form of topdressing. When the root absorption capacity is poor in the later stage, foliar topdressing is more direct and effective, and can also effectively prevent the harm of dry hot wind. The main types of foliar spraying are urea, monopotassium phosphate, micro-fertilizers, etc., with a concentration between 0.5-2%. Spraying is generally carried out before 10 a.m., after 5 p.m. or on cloudy days, and if it rains after spraying, it must be sprayed again.