How to prevent and treat nitrogen Nutrition Disorder in Wheat

Symptoms of nitrogen deficiency in wheat: slow plant growth, short individuals, reduced tillers; faded leaves, yellowing of old leaves, premature senescence and withering; stems and leaves often reddish or purplish red; slender roots, reduced total roots; incomplete spike differentiation and small spike shape.

Symptoms of excess nitrogen in wheat: excessive growth leads to overgrowth; leaf area increases and leaf color deepens, resulting in depression; mechanical tissue is underdeveloped, easy to lodge, susceptible to diseases and insect pests, yield reduction is particularly serious, quality becomes worse.

If the soil with poor sand and organic matter does not apply base fertilizer or a large amount of organic fertilizer with high C / N ratio, the symptom of nitrogen deficiency is easy to occur. The previous crop applied too much nitrogen, topdressing nitrogen too much, too late, partial application of nitrogen fertilizer, nitrogen excess is easy to occur.

The diagnostic indexes of soil available nitrogen (N) from tillering stage to jointing stage were as follows: less than 20 mg / kg for deficiency, 20 mg / kg for potential deficiency, 30 mg / kg for normal, and higher than 40 mg / kg for high or excessive. When the total nitrogen content (N) of functional leaves at jointing stage was lower than 35 mg / kg (dry weight), it was deficient, 35-45 mg / kg was normal, and higher than 45 mg / kg was excessive.

The prevention and control measures of wheat nitrogen deficiency disease are mainly to improve soil fertility and improve soil nitrogen supply capacity; when applying a large number of organic fertilizers with high C / N ratio such as straw, we should pay attention to the application of available nitrogen fertilizer; in ploughing and soil preparation, apply a certain amount of available nitrogen fertilizer as base fertilizer; for nitrogen deficiency caused by uneven soil fertility, it is necessary to apply available nitrogen fertilizer in time.

The prevention and control measures of wheat nitrogen excess are mainly according to the nitrogen demand characteristics of crops at different growth stages and the nitrogen supply characteristics of soil, timely and appropriate amount of nitrogen fertilizer, strictly control the amount of nitrogen fertilizer, and avoid topdressing nitrogen fertilizer too late; under the premise of reasonable rotation, on the basis of rotation, determine the appropriate amount of nitrogen application; rational application of phosphorus and potassium fertilizer to maintain the balance of nitrogen, phosphorus and potassium in the plant.