When is the best time to apply urea as a topdressing to wheat?
SummaryWheat can be topdressed with urea during the spring greening stage of wheat, and the wheat greening stage lasts about 30 days. Methods of topdressing wheat with urea: urea can be sprayed on the outside of wheat roots at a concentration of 2%; usually 2 jin of urea mixed with 100 jin of water can be sprayed on 1 mu of wheat field, once every 8-10 days, for a total of about 3-4 sprays. Taboos for topdressing wheat with urea: it must not be mixed with alkaline fertilizers such as ammonia water, plant ash, and ammonium bicarbonate.
1. Suitable time for topdressing wheat with urea
1. Urea can be topdressed during the spring greening stage of wheat. The wheat greening stage refers to when more than half of the wheat seedlings in the field in early spring have heart leaves that have grown out by 1-2cm, which is called “greening”. From the beginning of wheat greening to before standing up, it lasts about 30 days, and it is the last period of the seedling stage, so it is called the wheat greening stage.
2. The development of wheat during this period is mainly rooting, leaf growth, and tillering. The wheat greening stage is also an important period for promoting the growth of late and weak seedlings, controlling excessive growth of vigorous seedlings, regulating the size of the seedling population, and determining the tillering rate.
3. During the greening stage, topdressing can be carried out according to the seedling stage. For type 2-3 seedlings with relatively poor growth before winter, as well as wheat seedlings with poor soil quality or excessive growth and fertilizer deficiency from early sowing, urea needs to be applied early or heavily.
4. Urea can be topdressed when the ground begins to thaw, taking advantage of soil moisture. This plays a very important role in promoting wheat seedling growth and increasing the number of wheat ears. However, for type 1 seedlings with a relatively large number of wheat seedlings, or wheat fields that are somewhat vigorous without fertilizer deficiency, there is no need to apply urea, and it can be postponed until standing up, so as to control ineffective tillering and achieve the purpose of increasing the tillering rate and the number of wheat ears.
2. Methods of topdressing wheat with urea
1. The amount used must be well controlled, and the suitable application rate is 16-24 jin per mu.
2. It must be applied evenly. If it is not even, it will cause wheat seedling burn and also waste urea.
3. Apply it as deeply as possible and cover it with soil, with a depth of 10-15cm being suitable.
4. Apply urea in advance. When topdressing in spring, it needs to be 5-8 days earlier than other nitrogen fertilizers.
5. It can be applied together with phosphorus and potassium fertilizers, so as to meet the nutrient needs of wheat.
6. Topdressing can be carried out outside the roots. Spray urea on the outside of wheat roots at a suitable concentration of 2%; generally 100 jin of water mixed with 2 jin of urea can be sprayed on 1 mu of wheat field, for a total of about 3-4 sprays, with an interval of about 8-10 days.
2. Taboos for topdressing wheat with urea
1. When topdressing wheat with urea during the greening stage, it must not be mixed with alkaline fertilizers such as ammonia water, plant ash, and ammonium bicarbonate.
2. It must not be applied on the ground surface. Urea easily dissolves in water. If it is broadcast on the ground surface without soil covering, the nutrients will dissolve in rainwater and be lost, and it will also stick to the leaf surface, causing wheat burn.
3. Do not carry out large-water irrigation after applying urea. Urea dissolves in water in the soil in molecular form. Although it can be adsorbed and stored by the soil, large-water irrigation or continuous irrigation after applying urea will cause the fertilizer efficiency of urea to be lost. Therefore, fine water soaking is preferable.