How to improve urea 46-0-0 application rate？

Urea is generally used for base fertilizer and topdressing of crops, because urea is a fast-release nitrogen fertilizer that can replenish nitrogen for plant growth in time and promote growth. When using urea for topdressing, the main forms adopted are roughly scattering, manual fertilizer application, large-scale fertilizer application machinery conditions and water flushing. From the perspective of improve urea 46-0-0 application rate and exerting fertilizer efficiency, what should be done?

1. The reason why urea 46-0-0 application rate are low

Urea 46-0-0 is the most commonly used nitrogen fertilizer, with a nitrogen content of 46%, but urea 46-0-0 application rate is low, generally only about 20-30%. Most of them are lost with water or volatilized after being applied to the soil.

The main reasons for urea loss: ① Determined by the characteristics of urea, after urea is applied to the soil, it cannot be directly absorbed and utilized by the roots of crops, but is hydrolyzed into ammonium carbonate or ammonium bicarbonate under the action of urease secreted by microorganisms, and is absorbed by the roots and adsorbed by soil colloids in the form of ammonium. However, under high humidity conditions or in alkaline soils, it is easy to generate ammonia volatilization. ② Lost with water, and some of the ammonium ions that are not adsorbed are lost with water infiltration into the ground under heavy rain or irrigation.

2.Measures to improve urea 46-0-0 application rate

1) Foliar topdressing

Foliar fertilization refers to fertilizing without applying fertilizer to the root system. Traditionally, both base fertilizer and topdressing are applied on the soil. This method is foliar fertilization. Fertilizer urea 46-0-0 is easily soluble in water and has strong diffusivity. It has a macromolecular structure and is easily absorbed by the leaves. The appropriate concentration does not harm the leaves. If there are problems with the root system of the vegetation or aging, foliar topdressing of urea is also very effective.

Fertilizer urea 46-0-0 is used as a foliar fertilizer. It is necessary to pay attention to different crops, and the concentration of urea spraying is also different: 0.3% for solanaceous fruits, 0.5-1% for leafy vegetables, 1-2% for cereals, and 0.5% for fruit trees. It is recommended to spray foliar fertilizer after 4 pm on a sunny day, because during this period, the transpiration of the leaves is relatively small, and the stomata on the leaves are open, which makes it easier for urea solution to be absorbed.

2) Early and deep application: First, early application. Urea needs to undergo a transformation process before it can be absorbed and utilized by crops after it is applied to the soil. Therefore, if the time of applying urea is the same as that of applying other nitrogen fertilizers, it will delay the effective period of nitrogen nutrition absorption by crops. Generally, it is used as topdressing 7 to 10 days earlier than the normal fertilization time. Second, deep application. Whether urea is used as base fertilizer or topdressing, it should be applied deeply and covered with soil. The specific method is: when used as base fertilizer, it should be applied to 20 to 30 cm of the soil layer, and spread evenly, so that the effective ingredients can be absorbed by soil particles and meet the needs of plant roots.

The application methods for topdressing include flushing with water, dissolving into mother liquor first and then flushing; using a manual fertilizer applicator or a fertilizer machine for deep application, with a depth of about 20 cm. For small-scale planting, the traditional method of deep fertilization by trenching and digging holes can also be used; mixed with several fertilizers: urea can be applied in combination with organic fertilizers, phosphorus and potassium fertilizers, and trace element fertilizers to meet the needs of various nutrients of crops, maintain soil nutrient balance, maximize nutrient utilization, and play the role of fertilizers in increasing production.

In summary, we understand how to increase the urea 46-0-0 application rate through foliar fertilization and early and deep application, thereby helping farmers reduce costs and increase efficiency.