How long after the application of urea is absorbed by plants how to use urea

How long after the application of urea is absorbed by plants how to use urea

Urea fertilizer is an indispensable chemical fertilizer in the field of agricultural cultivation, but do you know how long urea is absorbed by plants after application? How to use urea better? For these questions, before using urea we still need to understand the solution.

A, how long after the application of urea is absorbed by plants

Urea usually needs to be converted into ammonium nitrogen under the action of urease before it can be absorbed by crops, and soil temperature will affect the time of urea into ammonium nitrogen.

When the soil temperature is at 10℃, it usually takes about 7-10 days to convert all urea into ammonium nitrogen, when the soil temperature is at about 20℃, it usually takes about 4 days, and when the soil temperature is at about 30℃, it usually takes about 2 days to complete the conversion.

When the temperature is at 25-30℃ and the soil moisture is at 70%, the peak of ammonification will generally occur after about 1 day and urea will be converted into ammonium nitrogen and then absorbed by the crop, but if there is not enough moisture in the soil, the urea conversion time will be slower.

Second, the conversion process of urea after application into the soil

Urea cannot be directly absorbed and used by crops. When urea is applied to the soil, it is dissolved in the soil solution in the molecular state and can be adsorbed by the soil colloid, and then undergoes a series of chemical change processes before it can be converted into a substance that can be absorbed by plants.

Urea needs to go through the action of urease in the soil, hydrolysis into ammonium carbonate or ammonium bicarbonate, in order to be absorbed and used by crops, and this process is related to factors such as soil ph, temperature and moisture.

Third, urea how to use better results

1, base fertilizer

When urea is used as a base fertilizer, generally combined with land preparation, 30% of urea with organic fertilizer, all the phosphorus, potassium fertilizer into the soil (deep mulch, to avoid the generation of ammonium nitrogen after the hydrolysis of urea, causing ammonia volatilization, resulting in reduced fertilizer efficiency).

2, chasing fertilizer

When used as a chasing fertilizer, generally in the critical period of fertilizer demand of the crop, about 7 days before the greater efficiency period, 60% of the nitrogen fertilizer into the soil, and then at a later stage, the remaining 10% of the nitrogen fertilizer into the soil.

The critical period of nitrogen requirement for wheat, corn and other cereal crops is at the tillering stage and spike differentiation stage, and the critical period of nitrogen requirement for cotton is at the boll stage.

Wheat nitrogen greater efficiency period in the pulling to pregnant spike, rice in the tiller to pulling period, corn in the trumpet period, sunflower in the bud period, soybeans in the first flowering period, tomatoes in the fruiting period, cabbage in the rosette period.

3、Foliar fertilizer

If it is a cereal crop, foliar spraying concentration is about 1.5-2%. If it is a leafy crop, foliar spraying concentration is about 1-1.5%.

Fourth, urea weed control effect is good

1, the effect of weed control with urea is relatively good, but need to pay attention to the use of methods, it is advisable to directional spraying, to avoid causing harm.

Usually in order to improve the weed control effect, you can generally add urea in the herbicide, a common combination of glyphosate + urea, but not all herbicides can be mixed with urea, such as glufosinate and urea will reduce the effectiveness of control after mixing.

2、If you want to use selective herbicides, it is generally not recommended to add urea, because it is easy to aggravate the efficacy of herbicides, thus making the original suitable crops to occur damage.

3, when adding urea in herbicides, the appropriate ratio of 2:1, the amount of urea added generally should not be too high, if too much is added, it is easy to cause the agent to fail or reduce the effectiveness, so it is difficult to achieve the effect of prevention and removal.