In the recent period, yellow leaves in vegetable greenhouses have once again become a topic of discussion among many vegetable farmers. Now that the temperatures in the shed have been higher, yellow leaves are more severe than in the cold season in winter. What is going on here?
It is understood that the recent yellow leaves of vegetables are mainly expressed in the top, middle and lower parts of the vegetables and the edges of the leaves. The reporter believes that these yellow leaves are mostly physiological diseases, mainly due to improper use of water, fertilizer, and medicine.
One, improper watering
1. Excessive watering at one time. The weather improved and the temperature rose. In order to boost the growth of the tree, some vegetable farmers were over-watered at one time, resulting in the lack of oxygen in the root system and the death or injury of the hair roots. As a result, the supply of water and nutrients was insufficient, causing the top leaves of the pepper to appear pale yellow and wilting. Dark yellow. In addition, excessive rooting of the water-carried roots leads to inadequate supply of iron and zinc, which can also lead to yellowing of the parietal lobe.
Solution: Watering should be based on the needs of different growth periods of vegetables and soil moisture. In the over-heating period of cold tail warmers, the requirement is to pour small water under the membrane, but not flood irrigation, and eager to achieve. If the watering is too large, the yellow leaves are promptly ploughed to reduce the soil moisture, and the iron-containing and zinc-containing leaf fertilizers are sprayed in time, and the rooting agent or rooting product is applied to solve the problem.
2. Control the water excessively. Concerned that the ground temperature is still low, fear that watering will cause rooting, or worry that excessive moisture in the shed is not conducive to disease prevention; or worry that plants are not conducive to fruit setting, etc. They cannot be watered in time, causing soil drought, root injury, endogenous auxin supply Insufficient, so that the lower leaves of the plant gradually dried up yellow, song volume, severe off.
Solution: After the weather is getting better, timely watering to ensure the growth of pepper required for water, but the water should not be too large, should be used to water the film under the method of pouring water, the water flow to the other end of the can stop the watering, to avoid capillary The injured new leaves also yellowed. At the same time, 400 times more foliar spraying of cytokinin was added 300 times more potassium dihydrogen phosphate.
Second, improper fertilization
1. Fertilizer overdose. The edges of the leaves turn yellow, and yellow ring leaves appear, mostly due to excessive salt precipitation causing mesophyll cells to burn. There are also some folds on the back of the leaves, the leaves do not stretch, the old leaves gradually fall off, the new leaves are severely closed when the song volume, the whole plant leaves yellow off.
Solution: According to the law of the crop's fertilizer requirements reasonable topdressing, not blind pursuit of high yield and over-recovery fertilizer. After the yellow leaves have been damaged by the fertilizer, the concentration of the fertilizer is diluted with water and fertilizer in a timely manner, and the rooting agent is poured and sprayed with 6,000-fold more nucleotides. Can also be applied to large source new fast gunners or antibiotics 968 red fertilization or Swiss biological bacteria fertilization and other bio-organic fertilizer to alleviate the salt ion concentration in the soil, while spraying the leaves of Sangiofo 600-800 times to promote leaf function recovery.
2. Inferior fertilization. This is one of the reasons for the lack of nutrients and the yellow leaves of vegetables.
Solution: If the heart is yellow, it may be deficient in zinc. It should be corrected by foliar spraying of zinc-containing leaves; the yellow leaves between the veins below may be magnesium deficiency, and foliar spraying of leaf-containing magnesium Solve it and so on.
Third, improper medication
The disease epidemic caused by the high humidity environment is one of the causes of yellow leaves of vegetables. However, due to improper use of medicines, the timing of disease prevention delays the occurrence of diseases, or the yellow leaves caused by phytotoxicity and gas damage are caused by the current yellow vegetables. The important reason for the leaves.
Solution: rational use of drugs to prevent diseases, to prevent the occurrence of disease yellow leaves. After the occurrence of yellow leaf, spraying cytokinin 300 times and adding ADD more than 6000 times can promote leaf recovery. At the same time, the nucleotide leaf fertilizer should be added with 500 times supplement nutrients to strengthen the leaf. Disease resistance.
At present, although the temperature is already high, the growth of vegetables is in the recovery stage. Blind use of water, fertilizer, and medicine can easily lead to yellow leaves. Therefore, the reporter reminded the vegetable farmers that they should start from the water, fertilizer, and medicine in the early spring and strengthen management. Yellow leaf is prevented from occurring.