Detailed Explanation of Key Fertilization Techniques for Winter Wheat Planting

The high yield of wheat is strongly dependent on soil fertility. Wheat fertilization should pay attention to the following aspects: First, the amount of nitrogen fertilizer applied to wheat fields should not be too large, nor too small. If there is too much nitrogen fertilizer in the early stage, it is easy to cause excessive growth in the early stage, and lodging in the later stage, reducing yield; if there is too little nitrogen fertilizer, then the wheat plants cannot reach the physiological state for safe overwintering, and severe freezing damage to the wheat will also cause yield reduction. Second, wheat is particularly sensitive to phosphorus. If phosphorus is deficient at the three-leaf stage, it will lead to fewer secondary roots, and delayed tillering or no tillering. If phosphorus is deficient after the three-leaf stage, it will delay heading, flowering and maturity, reduce the number of grains per spike, and lower the 1000-grain weight. The number of spikes per mu, the number of grains per spike, and the 1000-grain weight are the three elements of wheat yield. If all three decline at the same time, yield reduction becomes inevitable. Third is potassium fertilizer. Potassium fertilizer determines the stress resistance of wheat, such as drought resistance, cold resistance, and lodging resistance. When wheat is deficient in potassium, the concentration of the cell sap in wheat decreases, the freezing point of the cell sap rises, and freezing damage is likely to occur.

Now that you know the above characteristics of wheat fertilizer requirements, wheat fertilization becomes simple. After several years of research experience by our bureau on soil testing and formula fertilization for wheat, a relatively good wheat fertilization method has been obtained:

In irrigated winter wheat areas, before wheat sowing, apply organic fertilizer and 60% of the chemical nitrogen fertilizer required for the whole growth period, and 100% of the phosphorus and potassium fertilizers, broadcast them, and then plow them into the soil. Fertilize according to the local soil and climate conditions in combination with the soil analysis situation of the local plant protection station. Under normal circumstances, 30-40 kg of compound fertilizer can be applied. 

In dryland winter wheat areas, because there is little precipitation during the wheat growth period, the effect of shallow topdressing is poor, so topdressing is generally not applied. Instead, organic fertilizer and chemical fertilizer are applied deeply all at once before wheat sowing.

Topdressing 

In irrigated winter wheat areas, in the early spring during the wheat green-up and jointing stage, in combination with spring irrigation, apply green-up fertilizer as topdressing. The topdressing is nitrogen fertilizer, and the application amount is 40% of the nitrogen requirement for the whole growth period.

1. Fertilization principles

(1) Apply sufficient base fertilizer. Increase the application of organic fertilizer to increase soil organic matter content, improve soil fertility capacity, and enhance the soil's ability to retain fertilizer and water.

(2) Heavily apply jointing fertilizer (topdressing). Apply jointing fertilizer according to the seedling condition. If wheat has many tillers, good seedling condition, and vigorous growth, it should be applied appropriately later; if wheat has few tillers, poor seedling condition, and weak growth, it should be applied appropriately earlier.

(3) Lightly apply booting fertilizer. For wheat fields with sufficient water and fertilizer and a tendency to lodge, spike fertilizer should not be applied. If the seedling condition and growth are good, spike fertilizer can be applied less or not at all. For wheat with insufficient water and fertilizer and a tendency to premature aging, spike fertilizer should be applied. Booting fertilizer can be applied to quickly supplement nutrients, increase grain weight, strengthen stems, and prevent lodging.

(4) Foliar topdressing. Late May each year is a season with frequent dry hot winds. Spray 0.2% potassium dihydrogen phosphate on the leaves 1-2 times, with an interval of 5-7 days, which can effectively prevent and control the harm of dry hot winds.

2. Fertilization amount for wheat 

The amount of nutrients absorbed for every 100 kg of wheat grain produced is determined by factors such as soil, climate (rainfall, temperature, light), variety, and yield. The statistical results of the Soil and Fertilizer Research Institute of the Chinese Academy of Agricultural Sciences are: N 3.0 kg/100 kg grain; P 0.40-0.65 kg/100 kg grain; K 1.7-3.3 kg/100 kg grain.

Determination of wheat fertilization amount

Most of the nutrients absorbed by wheat come from fertilizers applied in the current season, but a considerable portion of the nutrients is also provided by the soil. In addition, the fertilizers applied in the current season are not 100% absorbed and utilized by plants. Some or most of them are adsorbed and fixed by the soil, or lost in various forms, so fertilizer has a utilization rate issue. Therefore, doing scientific and reasonable fertilization is very necessary.