Seven precautions for winter vegetables to be "washed with water"

vegetable fertilization

As a common fertilization method for protected vegetables, washing fertilizer with water is widely used by vegetable farmers because of its convenience, speed and labor saving. However, entering the cold winter season, fertilizer irrigation often causes some problems that are unfavorable to crop growth. The following is a brief introduction to the precautions for winter vegetable irrigation and fertilization.

First of all, the application amount should not be too large. In winter, the greenhouse temperature and ground temperature are low. Under such environment, the absorption and utilization rate of fertilizer by roots of vegetables is low. If it is still applied according to the conventional application rate, it will lead to a large amount of fertilizer accumulation in the soil, which will increase the soil concentration, damage the roots of vegetables, cause root burning, red roots and other phenomena, and seriously cause wilting of leaves, dead fruits or dead trees.

Second, the amount of water should not be too large. During the winter season, lower water temperatures have a great impact on vegetables. Well water poured into the shed is generally 10~14℃, fertilizer washed with water after application, the ground temperature significantly decreased, soil permeability will also deteriorate, will cause root rot, resulting in yellow heart leaves of vegetables, affecting the normal growth of vegetables.

Third, we must prevent the occurrence of gas hazards. Vegetables in protected facilities are closed for a long time in winter. Nitrogen fertilizer or other nitrogen-containing fertilizers will release nitrogen under the action of soil microorganisms. Because of long time without ventilation, harmful gases such as nitrogen accumulate in the shed. When the concentration is high, the stems and leaves of vegetables will be discolored. Even if the use of amino acids, fulvic acid and other fertilizers, the release will not be timely will also cause gas harm. Therefore, in most areas of Henan Province, in the low temperature season from late December to early February, it is necessary to avoid using fertilizers with large nitrogen content to avoid the harm of gas damage.

Fourth, look at soil moisture. When soil moisture is too large, do not rush to apply, so as not to affect soil permeability, resulting in root rot, heart leaf yellowing and other hazards. If you are in urgent need of supplementary fertilizer, you can apply foliar fertilizer first, and then flush fertilizer when the moisture content is appropriate.

Fifth, look at the weather. Choose to carry out when the weather turns clear after the cold front, so as to avoid the occurrence of continuous cloudy days after the rush. After washing fertilizer, it is difficult to recover the ground temperature due to cloudy days. The humidity in the shed increases, which will cause great damage to vegetables and increase diseases.

Sixth, it is necessary to raise the ground temperature in time. Generally, on the day or the next day after fertilizer washing, the temperature of the shed is increased by 2~3℃ by closing the tuyere properly, so as to increase the ground temperature and eliminate and alleviate the adverse effects of cold water washing fertilizer.

Seventh, after the fertilizer should be timely wet. It can be combined with raising the temperature of the shed, first raising the temperature to 30℃, reducing the relative humidity and then releasing the air and moisture to reduce vegetable diseases and insect pests.

In short, winter irrigation fertilizer should follow the principle of "less amount, better days, and higher temperature after fertilization" to ensure the safety of vegetable production.