How to use urea correctly in agricultural production

1, balanced fertilization

Urea is pure nitrogen fertilizer, does not contain a large number of elements necessary for crop growth in the phosphorus, potassium, therefore, when doing fertilizer should be based on soil testing, the use of formula fertilization techniques, balanced application of nitrogen, phosphorus, potassium fertilizer. Firstly, apply all the phosphorus and potassium fertilisers and some of the nitrogen fertilisers (around 30%) required for the whole crop period, combined with the bottom of the whole field. Then apply the remaining 70% of the nitrogen fertiliser (urea can be used) as a follow-up fertiliser, of which about 60% is applied during the critical period of the crop's fertiliser requirements and maximum efficiency, and about 10% during the later stages. Only nitrogen, phosphorus, potassium 3 kinds of fertilizer reasonable cooperation, scientific application into, can make the chase urea utilization rate increased.

2, the right time to chase the application

In agricultural production can often see some unreasonable fertilization phenomenon: every year after the beginning of spring wheat greening period, farmers take the opportunity to water the greening water will urea scattered or flushed into the wheat field; corn seedlings, farmers in the rain before the urea scattered into the field; cabbage seedlings with watering will urea flushed; tomatoes in the seedling watering when flushed urea, etc.. This is a good way to apply urea, although the fertilizer used, but the waste phenomenon is serious (ammonia volatilization, urea particles with water loss), but also lead to excessive nutrient growth, wheat, corn late fall, tomato "blow flowers", cabbage package heart delayed and other undesirable phenomena occur.

Each crop has a specific critical period for the uptake of nitrogen, phosphorus and potassium (i.e. a period when the crop is particularly sensitive to the uptake of a particular element). A lack of fertiliser (nitrogen, phosphorus and potassium) during this period will reduce crop yield and quality and have a huge impact, which cannot be reversed even if sufficient fertiliser is applied later. In addition, there is a maximum efficiency period, i.e. the period when fertiliser is applied to the crop to obtain higher yields and the crop is most efficient in using fertiliser. The above analysis shows that only in the nutrient critical period and maximum efficiency of the crop fertilizer chasing period, in order to improve the utilization rate of fertilizer, so that the crop to achieve high yields, quality.

Urea should be applied 1 week before the critical period of nitrogen demand and maximum efficiency of the crop. Different crops have different fertilizer critical period, maximum efficiency period, should be treated differently, reasonable application. For example, the critical period of nitrogen requirement for wheat and maize is at the tiller stage and the spike differentiation stage, and cotton is at the boll stage. The maximum efficiency of nitrogen in wheat is from the tiller to the ears, rice is from the tiller to the tiller, corn is in the trumpet stage, tomato is in the fruiting stage, cabbage is in the rosette stage, sunflower is in the bud stage, soybean is in the first flowering stage, etc.

3、Fertiliser at the right time

Urea is an amide fertilizer, need to be converted into ammonium carbonate is adsorbed by the soil colloid, and then absorbed by the crop, the process takes 6 to 7 days, during which the urea is first dissolved by the moisture in the soil, and then slowly transformed into ammonium carbonate, therefore, urea to do fertilizer application, should be applied in the crop's nitrogen demand critical period and fertilizer maximum efficiency period about 1 week before the application, not too early or too late.

4, deep application of mulch

Improper application methods are very likely to cause urea loss with water, ammonia volatilisation and other nitrogen loss phenomenon, waste of fertiliser, labor, but also greatly reduce the utilization rate of urea.

The correct method of application is: in corn, wheat, tomatoes, cabbage and other crops, should be 20 cm from the crop, digging 15-20 cm deep hole, the fertilizer will be applied to the soil with soil cover tightly, in the soil is not too dry after 7 days of watering. When the soil is seriously dry and watering is necessary, it should be lightly watered once, not in large quantities, to prevent urea from being lost with the water. When applied on rice, should be used to sprinkle, after application to keep the soil moist, 7 days can not irrigate, wait for the fertilizer fully dissolved by the soil adsorption, can be watered a small water, and then dry 5 to 6 days.

5, foliar spraying

Urea is easily soluble in water, strong diffusion, easy to be absorbed by the leaves, less damage to the leaves, suitable for extra-root fertilizer, can be combined with crop pest control foliar spraying. However, when doing extra-root fertilisation, choose urea with no more than 2% diurea content to prevent damage to the leaves. The concentration of extra-root fertiliser varies from crop to crop. Spraying should be done after 4pm, when transpiration is low and leaf stomata are gradually opening, which is conducive to the full absorption of the urea solution by the crop.