How does leaf yellow do?
Whether it is a potted plant at home or crops in the field, it is common to find that the leaves of the plant begin to turn yellow, and over time the leaves will wither, and eventually fall off. Plants live by photosynthesis in their leaves and produce organic matter. If the leaves are gone, it means the plant is near death.
1. Turning yellow from being too wet
Because soil moisture is excessive, causes soil hypoxia, and makes root breath difficult. Water absorption and fertilizer absorption of crop roots were blocked, and growth could not be carried out normally, leading to light yellow parietal leaves of new branches of seedlings, and the old leaves also became dark and yellow, and then withered and died. In this case, water should be drained in time to control the amount of irrigation.
2. Turning yellow from being too drought
Drought will wilt the seedlings. Photosynthesis declines at this time of growth and pause, photosynthetic product transportation is blocked, and plants breath to consume large amounts of organic matter. As water is redistributed in the plant, the new leaves take water from the old leaves, causing the old leaves to fall off. In this case, irrigation can be timely according to the degree of soil moisture and leaf changes.
3. Turning yellow from being lack of light
The light intensity required for normal plant growth is more than twice the light compensation point. Lack of light can cause plant cells to differentiate, thin stems and branches, and leaves to turn yellow. This kind of situation can take preventive measures is to increase illumination, greenhouse plants can be an artificial fill light, choose a different color plastic film to adjust the light quality, in order to increase output, improve quality or reduce the role of pests and diseases.
4. Turning yellow from suffering insert pest
In the process of seedling cultivation, often by the infestation of pests, especially a variety of leaf-eating and thorn sucking mouthparts of pests, harm the leaf or suck the leaf juice, resulting in leaf shrinkage, curl, so that the leaf spots, yellow and other phenomena. In order to avoid this situation should pay attention to observation, early prevention, in view of insect pests, and timely and appropriate disease spray.
5. Turning yellow from disease
Nursery seedlings often suffer from diseases, such as blight, rust, leaf blight, etc., which affect the survival rate of seedlings and make plants stunted. Accordingly, want to often observe seedling leaf and growth tendency, undertake medicament disinfection processing to seedling bed soil regularly, and eliminate the bacterium of the cause of disease inside the soil. Therefore, crop disease control is extremely important, once the disease is found, to prevent and control in time.
6. Turning yellow from being lack of trace element
In addition to a large number of elements such as nitrogen, phosphorus, and potassium indispensable, crops are also very sensitive to some trace elements, lack of which will cause disorder of crop physiological function, resulting in crop suffering disease, also shown in leaf color, such as lacking iron, zinc, magnesium, sulfur, manganese, will lead to yellow leaves. The deficiency of trace elements is mainly caused by long-term non-changed soil or a long-term single application of nitrogen fertilizer. Therefore, every other year to the seedbed soil improvement, pay attention to the use of organic granular fertilizer.
7. Yellowing caused by fertilizer
Fertilizer too much, or too little will have a bad effect on seedlings. On one hand, fertilization too thick, too much, will cause plant infiltration and transport blocked, new leaf hypertrophic, leaf folds and do not stretch, and old leaves yellow and do not fall off. On the other hand, when lacking fertilizer, can cause tender branches, internode long, thin leaves, and yellow.
Therefore, reasonable organic fertilization can improve plant photosynthesis. For example, N, and Mg element promotes the growth of branches and leaves, expands the area of photosynthesis, increases the content of chlorophyll, and improve the photosynthetic rate. N, Ca, Zn element prolong leaf life and photosynthesis time. P, K, and B elements improve the transport and distribution of photosynthetic products.
In addition, reasonable organic fertilization can improve the soil environment and create a good living environment for plants. Such as the application of organic fertilizer can increase the soil aggregate structure, not only improve the soil water, gas, and temperature, promote the growth of the root system and the absorption of fertilizer, but also promote the activities of soil microorganisms, accelerate the decomposition of organic matter, improve the supply of nutrients.
8. Yellowing caused by pH value
The pH of seedbed soil can affect the solubility of minerals. In alkaline soil, iron, calcium, phosphorus, magnesium, zinc, and other soluble compounds are easily formed, which will reduce the absorption of these elements by plants and cause yellow leaf disease. When the soil is too acidic, iron, aluminum, manganese, and others dissolved too much, plants will also absorb excessive poisoning.
Therefore controlling the pH of the soil is an important way to ensure normal growth of seedlings, the excessive alkali soils can be more ammonium salts, and the acidic soil can be applied with more basic fertilizer, to adjust the pH value of the soil, so that it is suitable for seedling growth.
9. Yellowing caused by pesticide
As a result of disease prevention insect, spray pesticide is improper or concentration is too large and causes crop harm, making leaves yellow and fall off.
Therefore, the use of pesticides at the same time, must be strictly in accordance with the instructions, according to a certain proportion of spraying, once there is harm, should be washed with water as soon as possible, in order to reduce drug resistance.
10. Turning yellow from being too cold
Spring sowing, as a result of low temperature, although above zero, but lower than the lower limit of the normal growth of seedlings temperature, so that the protoplasm in the plant cell viscosity increases, cell osmosis effect decreases, resulting in lower respiratory rate, absorption of water, mineral elements slow down, they will appear young leaves yellow wilting. At this time, one should pay attention to the cold.
Post time: May-07-2022