What are the problems with yellow leaves in grapes? There are many reasons for the yellowing of the leaves of grapes, one of which is the lack of nutrients, and the other is an infective disease caused by the infestation of pathogenic fungi. In the absence of magnesium, iron, sulfur, etc. will cause the leaves to yellow. Magnesium deficiency causes yellowing of old leaves; yellow irons cause new leaves to yellow, and veins are green; and yellow leaves caused by sulfur deficiency are yellow veins and green leaves; this is magnesium deficiency, iron deficiency, deficiency The difference in the symptoms of sulfur. Infectious diseases Grape downy mildew usually causes yellowing and necrosis of the leaves.
Sprayed back ferrous sulfate, why not use? If it is caused by iron deficiency yellow leaves, spraying once is not enough, generally in the early stage of growth spray 7 to 10 days, continuous spray 3 to 4 times. The spraying concentration of ferrous sulfate should be controlled at 0.2%. In order to enhance the iron absorption of grape leaves, a small amount of vinegar and 0.3% urea can be added when ferric sulfate is sprayed, which has a good effect on the promotion of iron absorption, utilization, and green transformation.
Last year, the grape produced a large amount of fruit. The tree was "tired" and caused the leaves to yellow. Is this justified? There is some truth. Excessive fruiting, over-application of chemical fertilizers, or application of unfamed organic fertilizers can cause poor root development and induce root rot. Judging from the condition of the grape roots, the roots are dark, with few hair roots and root rot, indicating that the ability of roots to absorb nutrients is limited. Even if various nutrients in the soil are sufficient, the root system is hard to absorb, so it will show The tree is weak and the leaves are yellow.
Is there any way to remedy this? This year will surely reduce production, but strengthening water and fertilizer management can still make up for some of the loss of production.
First, it is necessary to strengthen the top dressing, that is, spraying foliar fertilizer. Root nutrient absorption is limited, it will add some from the foliage.
Second, fertilizers that promote root growth, such as high-quality bio-organic fertilizers, can be used. Fertilizers can use zinc fulvic acid fertilizers because zinc fulvic acid fertilizers can stimulate the growth of roots and restore root vitality as soon as possible.
Third, we must pay attention to the autumn fertilization of grapes, and do not care if you do not pick grapes. Not paying attention to autumn fertilization can easily cause problems in the second year of growth. Because the early spring buds, the temperature in most regions is still relatively low, and the absorption capacity of the root system is very limited, so that the bud fertilizer applied in early spring is difficult to play a role. When the root system is unable to supply enough nutrients, the neatness and robustness of new shoots are mainly determined by the accumulation of nutrients in the shoots, so the post-harvest management of the grapes is critical. If the fruit is not replenished with timely restoration of tree vigor, the leaves will be yellow leaves and fall off prematurely, and the nutrients in the leaves will not return in time. If the nutrition in the branches is not enough, the quality of the buds and the leaves of the next year will be affected. After a long period of germination, the entire leaf appears yellow, and the growth is slow like de-fertilization.
Fourth, try not to break the dormancy of grapes by applying a sleep breaker to pursue the morning market. Short sleep time can also result in insufficient nutrient accumulation and affect budding.
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