Precautions for applying foliar fertilizer

What is the role of foliar fertilizer?

1. Make up for the lack of root fertilization

When the root system is underdeveloped or the root system is declining during the crop growth period, the root system has a weak ability to absorb nutrients. Foliar fertilization can strengthen the seedlings and reduce the grains and increase the yield. Or when the soil environment is unfavorable for the growth of crops, such as excessive water, drought, excessive soil acidity, and excessive alkalinity, which hinder the absorption of crop roots, and the crop needs to quickly resume growth; or during the process of crop growth, the crop has shown Certain nutrient element deficiencies, in the above two cases, because the use of soil fertilization requires a certain period of time for nutrients to be absorbed by the crop, which cannot meet the needs of the crop or alleviate the symptoms of crop deficiency in time, then use foliar fertilization, then It can make nutrients quickly enter the plant body, supplement nutrients, solve the problem of nutrient deficiency, and meet the needs of crop growth and development.

2. Avoid fixing or transforming nutrients in the soil

The soil is a complex colloid. After fertilizer is applied to the soil, certain nutrients are adsorbed by the soil colloid, or sediments are formed due to changes in soil pH. Such as P, Zn, Cu, Mo, etc., are easily fixed when applied to the soil and reduce fertilizer efficiency. Foliar fertilization can avoid fixation and improve fertilizer efficiency. Some physiologically active substances are easy to decompose in the soil and transform to affect the effect. Foliar fertilizer is applied to the leaves and transported through sieves, ducts or plasmodesmats at a close distance to avoid the transformation and leaching of nutrients in the soil. Improve fertilizer efficiency and fertilizer utilization.

3. Reduce soil pollution

Applying a large amount of nitrogen fertilizer to the soil is easy to cause the accumulation of nitrate in groundwater and vegetables, which is harmful to human health. About 75% of the nitrate absorbed by humans comes from vegetables. If the method of foliar fertilization is adopted, the amount of soil fertilization should be appropriately reduced. It can reduce the nitrate content in the plant and the residual mineral nitrogen in the soil. On the saline soil, soil fertilization may increase the concentration of the soil solution and aggravate the soil salinization. Adopting foliar fertilization measures not only saves the amount of fertilization, but also reduces the pollution of soil and water sources, which is an effective fertilization technology for environmental protection.

4. Prevention and treatment of physiological diseases

After applying foliar fertilizer, it can meet its needs for related nutrients, change the composition of the microbial flora on the leaf surface, such as making the spore germination and community growth of Erysiphe graminis down; promote urease, phosphatase, ascorbic acid oxidase, carbonic acid The activity of anhydrase and arginase is increased to prevent and control certain physiological hazards.

What happens if you overuse foliar fertilizer?

When using foliar fertilizer, three or four kinds of fertilizer should be compounded at one time to make the plants absorb more nutrients. Not only is nutrition repeated, but this statement is also undesirable. Foliar fertilizer should be supplemented selectively according to the growth of the vegetables, otherwise some excess nutrients will cause leaf burns and other side effects.

For example, certain foliar fertilizers with the properties of conditioners can promote plant growth at normal concentrations, but if the concentration is increased, it will play a role in controlling growth. There is also a situation where nutrients can antagonize absorption. For example, potassium dihydrogen phosphate and calcium fertilizer are mixed, and potassium fertilizer and calcium fertilizer are mutually exclusive for absorption.