After emergence of wheat, due to the influence of natural conditions and cultivation measures, various types of weak seedlings are often formed. For symptomatic management of the seedlings, the following are introduced:

 

　　 1. The weak seedlings caused by soil nitrogen deficiency are: the seedlings are weak and erect, the tillers are reduced, the leaves are narrow and short, and the lower leaves start from the tip of the leaves, gradually turning yellow and dry, and developing to the upper leaves. Management points: 7 to 8 kg of urea per acre , or 20 to 25 kg of ammonium bicarbonate .

 

　　 2. The weak seedlings caused by soil phosphorus deficiency are: poor root development, secondary roots are weak and weak, leaf color dark green dull, leaf tip and leaf sheath are purple-red, plants are thin and small, tiller is reduced. Management points: 20 to 30 kilograms of calcium phosphate per acre , the earlier the effect is, the better.

 

　　 3. The weak seedlings caused by soil drought are: mostly occurring in wheat fields with insufficient bottom or running through the wind. The characteristics are: slow tillering, grayish green leaves, short heart leaves, slow growth or stagnation (the masses call it " The shrinking heart seedlings ) , the middle and lower leaves gradually turn yellow and dry, and the roots are few and thin. Management points: In combination with irrigation, 15 kg of ammonium bicarbonate is applied per mu .

 

　　 4. The weak seedlings caused by soil over-humidity usually show: the leaves are light purple, the tillers are born slowly, and the tips are white and dry when severe. Management points: first in time, deep and medium tillage, sputum ventilation, and then apply a small amount of quick-acting fertilizer to promote early seedlings.

 

　　 5. The weak seedlings caused by excessive sowing are: the seedlings are crowded and the plants are thin and slender. Management points: first grasp the sparse seedlings, especially the “small seedlings” on the ground, on the ground and in the field. It is necessary to early sparsely and sparsely, and then apply a small amount of nitrogen and phosphorus quick-acting fertilizer to make up for the excessive consumption of soil nutrients, and promote the wheat seedlings. Weak and strong.

 

　　 6. The weak seedlings caused by shallow sowing are: because the tillers are too close to the surface, the water nutrient conditions are poor, and the root growth and axillary bud development are inhibited. Therefore, the roots and ticks are usually reduced, and the plants are weak and vulnerable. Frozen and dead. Management points: Apply organic fertilizer, cover the grass properly, and cover the roots of the soil; when the aboveground part of the plant basically stops growing, break the soil. The thickness of the cover soil is such that the branching section is about 3 cm below the surface of the earth ;

 

　　 7. The weak seedlings caused by sowing too late are: due to the short growth period before winter and insufficient accumulated temperature, the wheat seedlings grow thin and have few tillers. Management points: mainly for composting, 15-20 kg of ammonium bicarbonate in the three-leaf stage ; wheat fields with poor soil moisture and fast water seepage, timely pouring water after the three-leaf period ( but suitable for soil moisture or poor water permeability) Block, it is not suitable to water before winter ) , the last time before freezing, pay attention to the roots of bauxite, to protect the seedlings for safe winter.

 

Source: China Agricultural Promotion Network