Urea usually contains a small amount of toxic biuret to plant. As the root topdressing urea, biuret content should not exceed 0.5%, but because some products contain more than 0.5% biuret, or multiple spraying urea, so that the accumulation of certain biuret in the plant, because biuret in the plant is not easy to decompose and make the plant poisoning. The symptom of poisoning is yellowing of leaf tip, this phenomenon is permanent, only new leaf just not have yellowing.

If we often gush urea to orange, in most cases, it will appear the disease of tip yellowing. When the area of tip yellowing is large, photosynthesis will be affected. Pineapple, lemon, potato, tobacco and coffee are more sensitive to biuret, easy to be poisoned. So it is essential to master the application of fertilizer.

Sometimes the phenomenmon of yellow leaves of Vegetable due to iron element is deficient, however, yellow leaves also often occur on clay ground, which is caused by poor permeability of clay soil. With the increasing application of organic fertilizer and straw fertilizer is the only way to improve soil permeability. Drugs can cause yellow leaves, such as some vegetables are allergic to some pesticides, fungicides sensitive, after the application of drugs caused by the leaves suddenly turn yellow.

So we not only master the ways to apply fertilizer, but also know what is the high-quality organic nutrient fertilizer manufactured by the professional organic fertilizer prodution line. The growth of crops needs essential n p k major elements, but also needs other microelements,single fertilizer cant meet the demands of crops growth for adequate nutrients. the application of organic fertilizer and npk compound fertilizer also can improve soil physical and chemical character and soil permeability. Soil structure is also the importment factor for high-quality and hity-yield crops

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