After emergence of wheat, due to the influence of natural conditions and cultivation measures, various types of weak seedlings are often formed. For weak seedlings, symptom management is introduced separately as follows: 1. The weak seedlings caused by soil nitrogen deficiency showed: the seedlings were thin and upright, the tillers reduced, and the leaves were narrow and short. The lower leaves started from the tips of the leaves and gradually became yellow and dry and developed toward the upper leaves. Management points: 7 to 8 kg of urea per mu, or 20 to 25 kg of ammonium bicarbonate. 2. The weak seedlings caused by the lack of phosphorus in soil showed: poor root development, less and weaker secondary roots, dark green and leafy leaves, purple tips on leaf tip and leaf sheath, and small and thin tillers. Management points: Use 20 to 30 kg of superphosphate per acre. The earlier the effect, the better. 3. Weak seedlings caused by soil drought are: Wheat fields that occur mostly in the bottom squat or run through the wind, characterized by: birth was slow, leaf color grayish green, leaves are short, growth is slow or stagnant (people call it " "Shou Xin Miao"), the middle and lower leaves turn yellow and dry, the roots are small and thin. Management points: Combine irrigation with 15 kg of ammonium bicarbonate per acre. 4. Weak seedlings caused by soil wetness usually manifest as: leaves pale purple, birth is slow, and when severe, the tip of the leaf turns white and dry. Management points: The first timely and deep cultivating ventilation, followed by a small amount of quick-acting fertilizer to promote early-onset seedlings. 5. The performance of weak seedlings caused by excessive sowing is: the seedlings are overcrowded and the plants are thin and slender. Management points: First, pay close attention to sparse seedlings, especially the “headings†in the fields, fields, and fields. Early sparse, sparsely populated, and then apply a small amount of nitrogen and phosphorus fast-acting fertilizers to make up for the excessive consumption of soil nutrients and promote the development of wheat. Weak turn strong. 6. Weak seedlings caused by super sowing show: because the tiller node is too close to the surface, the condition of water nutrients is poor, so that the growth of the root system and the development of the axillary buds are inhibited. Therefore, the roots and pods are usually reduced, and the plants are weak and vulnerable. Frozen withered. Management points: Spreading organic fertilizer, appropriate covering grass, and ramming soil around the roots; when the above-ground parts of the plant basically stop growing, the roots cover the soil. The thickness of the cover soil is such that the tiller section is about 3 cm below the surface. 7. Weak seeding caused by sowing late performance: more due to a short growing period before winter, the accumulated temperature is insufficient, resulting in thin wheat seedlings growth, fewer tillers. Management points: mainly fertilizer supplementation, applying 15-20 kg of ammonium bicarbonate in three-leaf stage; poor wheat field with poor soil moisture and water seepage; timely pouring of drowning water after the three-leaf stage (however, suitable moisture content or poor soil moisture and poor water permeability Block, before the winter should not be watered), the last time before the end of the seal larvae, we must pay attention to the ram soil to protect the seedlings safe winter. Precision Ultrasonic Metal Welding Machine Titanium Welding Machine,Laser Welding Machine For Stainless Steel,Brass Welding Machine,Gas Metal Arc Welding Machine Dongguan Jinwang Ultrasonic Equipment Co.,Ltd , https://www.jwultrasonic.com