The content of zinc in crops is generally a few parts per hundred thousand to a few parts per million of dry matter weight. Although the content is very small, the effect is great. For example, “shrunk seedlings”, “stiff seedlings”, and “settle-sitting” in rice, “white bud disease” in corn, “small leaf disease” in citrus and other fruit trees, and “bronze disease” in tung trees are all related to the lack of zinc. . So what is the role of zinc in plants? We will explain it from the following aspects.
(1) The role of zinc
1) As a component or activator of certain enzymes:
Research now finds that zinc is a component of many enzymes. Many important enzymes in plants (such as alcohol dehydrogenase, copper-zinc superoxide dismutase, RNA polymerase, etc.) must have the participation of zinc to exert their normal physiological effects. In addition, zinc is an activator of many enzymes. If zinc is deficient, the activities of protease and nitrate reductase in plants will be greatly reduced. Together, they have a greater impact on plant growth and metabolism.
2) Effect on carbohydrates:
The effect of zinc on carbohydrates is mainly achieved through photosynthesis and sugar transport, and some enzymes that require zinc are also involved in carbohydrate metabolism. When zinc is deficient, plant photosynthesis efficiency will be greatly reduced. Because zinc deficiency will affect enzyme activity, it will cause a decrease in chlorophyll content, and abnormalities in the structure of the mesophyll and chloroplasts.
3) Promote protein metabolism:
Since zinc is a component of many enzymes in the protein synthesis process, if plants are deficient in zinc, the rate and content of protein synthesis will be hindered. The effect of zinc on plant protein metabolism is also affected by light intensity.
(2) How to use zinc
1. Zinc fertilizer is best used on crops that are sensitive to zinc, such as corn, rice, peanuts, soybeans, sugar beets, beans, fruit trees, tomatoes, etc.
2. Use as base fertilizer every other year: Use about 20-25 kilograms of zinc sulfate per hectare as base fertilizer. It should be applied evenly and every other year. Because zinc fertilizer has a long residual effect in the soil, it does not need to be applied every year.
3. Do not dress seeds together with pesticides: Use about 2 grams of zinc sulfate per kilogram of seeds, dissolve it in a small amount of water, spray it on the seeds or soak the seeds, wait until the seeds are dry, and then treat with pesticides, otherwise the effect will be affected.
4. Do not mix it with phosphate fertilizer: Because zinc-phosphorus has an antagonistic effect, zinc fertilizer should be mixed with dry fine soil or acidic fertilizer, spread on the surface, and dug into the soil along with the cultivated land, otherwise the effect of zinc fertilizer will be affected.
5. Do not apply surface application but bury it in the soil: When applying zinc sulfate, apply about 15 kilograms of zinc sulfate per hectare. After trenching and covering with soil, the effect of surface application is poor.
6. Do not soak the seedling roots for too long, and the concentration should not be too high. A concentration of 1% is appropriate and the soaking time is enough for half a minute. If the time is too long, phytotoxicity will occur.
7. Foliar spraying has good effect: Use zinc sulfate solution with a concentration of 0.1~0.2% for foliar spraying, spray once every 6~7 days, spray 2~3 times, but be careful not to pour the solution into the heart leaves to avoid Burn plants.
(3) Dangers of excessive zinc:
What are the dangers of excessive zinc? For example, the roots and leaves will grow slowly, the young parts or tops of the plants will turn green and appear light green or off-white, and then red-purple or reddish-brown spots will appear on the lower surfaces of stems, petioles, and leaves. Root elongation is hindered.
Post time: Aug-07-2024
