1. Standards for healthy vegetable root systems
(1) Color of normal root systems
The color of the old root skin of vegetables is relatively pure, the color of new roots is white, and the color of secretions is milky white or nearly colorless and transparent. Judging from the color, if the above three conditions are met, it is a relatively normal and healthy root system.
(2) Shape of normal root systems
The root system of vegetables grows in all directions. Generally speaking, there is no fixed direction, nor a primary or secondary direction. As vegetables continue to grow, the developing root system will also extend in all directions more evenly. However, if watering or fertilization is improper, there will be a phenomenon of more roots on one side and fewer roots on the other side. Generally speaking, the main root of vegetables is conical, the fibrous root is umbrella-shaped, and the growth of roots is orderly from new to old. Such a root system is a normal and healthy root system.
2. Main reasons affecting the normal growth and development of the root system
(1) Improper planting methods lead to root rot and seedling death
Some growers plant more crops in early spring and the planting time is relatively concentrated, which leads to incorrect planting methods for some crops, such as planting too deep, causing the root system of the crops to fail to recover immediately after planting, resulting in seedling death and root rot.
(2) Improper watering
After the vegetables are planted, if watering is too frequent or too much, root rot may occur.
(3) Fertilizer damage
The organic fertilizer used is not fully decomposed, resulting in crop seedling death. Or the concentration of fertilizer applied is increased too quickly or too high, which is also very likely to cause root burn.
3. Main technical measures for root care and root protection
(1) Control the amount of watering
"Dry roots grow, wet seedlings grow", after planting vegetables, the water supply should be moderately controlled, not excessive, just water thoroughly.
(2) Increase the application of phosphorus and potassium fertilizers
In soilless cultivation, applying phosphorus to the leaves can not only promote the formation and growth of early roots, but also improve the ability of plants to adapt to external environmental conditions. Potassium has the functions of ensuring the smooth progress of various metabolic processes, promoting plant growth, resisting diseases and pests, and resisting lodging. Therefore, sufficient potassium fertilizer should be applied to promote root development.
(3) Increase the application of organic fertilizers
The application of organic fertilizers can increase the organic matter content in the soil and provide an excellent environment for the growth and development of the root system.
(4) Use rooting functional fertilizers
When crops cannot take root well, rooting fertilizers need to be applied. Reasonable application of amino acids, alginic acid, humic acid, and chitin rooting agents can promote the synthesis of nutrients by photosynthesis in newly planted vegetable plants and transport them to the root system, so as to achieve the effects of rapid growth of new roots, more roots, strong roots, and shortened seedling acclimatization time.
(5) Prevention and control of root diseases
The main root diseases of vegetables include Fusarium rot, Phytophthora root rot and wilt. Root diseases are different from stem and leaf diseases. Stem and leaf diseases can be seen after the lesions appear, but when the root diseases show symptoms, most or even all of the plant roots have died, and it is too late to use pesticides to prevent and control them. Through observation, if a small number of vegetable plants in the greenhouse wilt, it is often a precursor to the occurrence of root diseases, and early inspection and diagnosis are required.
To prevent and control root diseases, root irrigation with pesticides is an effective measure. It is necessary to choose a reasonable root irrigation method according to the location of the root disease. For diseases at the base of the stem, the stem can be sprayed directly; for root rot and wilt, attention should be paid to the prevention and control methods to ensure that the pesticide reaches the diseased part. It can be done by digging holes or using special tools to irrigate the roots.
