After emergence of wheat, due to the influence of natural conditions and cultivation methods, various types of weak seedlings are often formed. In order to facilitate symptomatic management, the causes of weak wheat seedlings were analyzed in terms of soil and sowing. Soil section 1. Soil drought occurs mostly in wheat fields with insufficient soil moisture or run through the wind. It is characterized by: the birth of the tiller is slow, the leaf color is grayish green, the heart is short, and the growth is slow or stagnant (generally called "mineral seedlings"). The lower leaves become yellow and dry, and the roots are small and fine. Management points: In combination with watering, topdressing 15 kg of ammonium per acre. 2. The soil is usually wet with pale purple leaves and is born slowly. When severe, the tips of the leaves turn 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. 3. Wet soil or saline soil usually shows poor root development and weak absorption capacity. The birth of tillers is slow and often accompanied by defertilization. The heavy-alkali-damaging plots often appear as patches of purplish red. "Old seedlings", 1-2 leaves of the seedling base yellow and dry, when severe, the seedlings die dead. Management points: Combine deep-middling cultivating, applying nitrogen-phosphorus compound fertilizer to open ditch, heavily saline-alkali-damaged land, apply salt pressure after top-dressing, and timely remove the loose soil to remove the compaction. 4. Hardness of soil plate Due to the lack of air in the soil, the roots are difficult to spread, resulting in short yellow wheat leaves. The tillers cannot appear on time. Management points: Watering in time, then deep cultivating tillage to remove the rigid layer. 5. The nitrogen-deficient seedlings were thin and erect, with fewer tillers and narrow and short leaves. The lower leaves started from the tips of the leaves and gradually became yellow and dry and developed toward the upper leaves. Management points: 7-8 kilograms of urea per mu, or 20-25 kilograms of ammonium bicarbonate, may be applied between rows or on water. 6. Phosphorus deficiency showed poor root development, secondary roots were weak and weak, leaf dark green and dull, tip and leaf tip were purple, plants were thin, and tillers were reduced. Management points: In combination with watering and ploughing, use 20-30 kg of superphosphate per acre. Open the ditch and chase between the rows. The sooner the recovery, the better. Seeding 1. The performance of sowing is too deep: the emergence is slow, the leaf tip is slender, the seedlings are not distributed, and the secondary roots are not long. Management points: First clear the earth with trees, and then topdress fertilizer (15 kg per mu for ammonium bicarbonate) to promote root and seedling development. 2. Too shallow seeding 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 tendons are usually reduced, and the plants are weak in yellow and are easily frozen to death. Management points: In conjunction with scratching, earthworms are encircled; when the above-ground parts of the plants basically stop growing, the earth is broken. Covering the soil thickness to make the tiller section about 3 cm below the surface is appropriate. If the soil is covered with soil, it is covered with clay and covered with sand, which can also improve the soil. 3. The late sowing was more due to the short growing period before the winter, and the accumulated temperature was insufficient, which led to the growth of the wheat seedlings being thin and thin, with fewer tillers. Management points: Mainly use paddling and replenishing fertilizer, and apply 15 kg of ammonium bicarbonate in the three-leaf stage; soils with poor soil moisture and fast water seeps; timely flooding after the three-leaf stage (however, suitable moisture content or soil viscosity, water seepage Poor land should not be watered before the winter), and the last time it is ploughed before freezing, it is necessary to pay attention to the soil and to protect the seedlings safely. IPL Hair Removal,IPL Laser Hair Removal,IPL Hair Removal Machine,IPL Laser Hair Removal Machine Shenzhen Jie Zhong Lian Investment Co., Ltd. , https://www.meizons.com