1, balanced fertilization
Urea fertilizer belongs to pure nitrogen fertilizer, which is rich in phosphorus and potassium. When it is used as base fertilizer, it should be used in combination with organic fertilizer to meet the nutrients needed by crops in the growth cycle, to avoid excessive growth or poor growth when a single fertilizer is used, and it should be blended according to the corresponding proportion.
2. Appropriate topdressing
Urea fertilizer is rich in nutrients, but the absorption of nutrients by crops has a certain critical period, so the growth will be weak when it is deficient, but too much dosage will also cause fertilizer damage. It is best to topdressing urea fertilizer during the growth period of crops and at the critical period of nutrition to improve quality and increase yield.
3. Deeply cover the soil
When urea fertilizer is applied in deep soil, it is suitable for corn, wheat and other crops and vegetable crops such as cabbage. It is best to dig a hole of 15 cm at a distance of 20 cm from the crops, apply urea fertilizer into the hole and cover it with thick soil, and water it properly when it is too dry.
4. Spraying foliage
Urea fertilizer is soluble in water, has certain diffusibility, is easy to be absorbed when it is used for topdressing outside roots, and has little damage to leaves. It is suitable for spraying in the vigorous period of crop growth combined with the prevention and control of pests and diseases, and the topdressing on leaves is best carried out after 16 pm, when transpiration is weakened and stomata of leaves are opened, which can absorb nutrients well.
Effects of urea on plants
1, adjust the amount of flowers
Urea can regulate the flower amount of plants, and the most typical example is that it can control the problem of apple size. When the apple is in the off-year, spraying 0.5% urea solution on the leaf surface 5-6 weeks after flowering, after spraying twice, the nitrogen content in the leaves can be increased, which can accelerate the growth of new shoots and inhibit the differentiation of flower buds.
2, thinning flowers and fruits
Spraying plants with a certain concentration of urea can also play a role in thinning flowers and fruits. According to the experiment of peach and nectarine with urea abroad, the purpose of thinning flowers and fruits can be achieved after spraying 1-2 weeks with urea with a concentration greater than 7.4%, but this effect is also different in different regions, so it is necessary to adjust the appropriate concentration according to different varieties.
3, pest control
Urea also has the function of preventing and controlling plant diseases and insect pests. The mixed solution of urea, washing powder and clear water in the ratio of 4:1:400 can be used to prevent and control aphids, red spiders, cabbage caterpillars and other pests on fruit trees, vegetables, cotton and other plants. The bactericidal effect of this mixed solution is over 90%.