An ideal application method that avoids separate application is to apply organic fertilizer first, and then apply urea, superphosphate, and potassium chloride to a reasonable formulation.
The second bogey and ammonium bicarbonate mixed urea applied to the soil, to be converted into ammonia can be absorbed by the crop, and its conversion rate under alkaline conditions is much slower than in acidic conditions. After ammonium bicarbonate was applied to the soil, the reaction was alkaline and the pH was 8.2-8.4. The combination of ammonium bicarbonate and urea will greatly slow down the conversion of urea to ammonia, which can easily lead to the loss of pyrolysin and loss of volatiles. Therefore, urea and ammonium bicarbonate should not be mixed or applied simultaneously.
The third bogey spreads urea on the ground and spreads it to the surface. It takes 4 to 5 days of conversion to be absorbed by crops at room temperature. Most of the nitrogen is volatilized during the ammoxidation process. The utilization rate is only about 30% if alkali is used. Soils with high levels of soil and organic matter will lose more nitrogen. Therefore, nitrogen cannot be applied on the surface.
Four bogey application of urea immediately after irrigation urea is an amine nitrogen fertilizer, must be converted into ammonia nitrogen after application can be absorbed by the crop. In the conversion process, due to different conditions such as soil quality, moisture, and temperature, the time is usually short and it usually takes 2 to 10 days to complete. If urea is applied immediately after irrigation or dry land is applied before heavy rain, urea will be lost immediately.
Author: Guo Ying