Yellow seedlings
In recent days, there have been yellowing phenomenon in the wheat fields of the field plots. After analysis, there are mainly several causes. 1. Drought causes yellowing of wheat leaves. This type of wheat occurs in the bottom pods and grabs the sown plots. When wheat roots absorb water from the soil and it is difficult to compensate for the consumption, their growth and development are affected and the leaves turn yellow and die severely. The performance of the field was that the whole wheat field was yellowed more uniformly, the tillers were delayed, the growth was slow or stagnant, the new leaves were short and the roots were small and fine. Therefore, sowing should be sufficient. 2. Straw returned to farmland shallow. The return of corn stalks can improve the soil and fertility. Now, the return of straw is large, and the plough layer is generally less than 20 cm, so that the roots of some wheat in the field are tied up on loose stalks and it is difficult to absorb them from the soil. Nutrients cause yellow wheat seedlings. Therefore, deep plowing and deep plowing are recommended. Deep plowing should be performed once every 3 years and the depth should reach 25 cm. 3. lack of fat. Insufficient nitrogen fertilizer or insufficient phosphate can cause yellow wheat. The lack of nitrogen in yellow wheat is due to the early sowing, insufficient application of basal fertilizer or low nitrogen content in base fertilizers, resulting in the yellowing of wheat leaves. The plants are small and weak, the tillers are few and weak, and the leaves of the seedlings are yellow. In this case, it is necessary to apply about 5 kg of urea per acre during the return period, and then apply 12-15 kg of urea per acre for the stand up or jointing period. The insufficient amount of phosphate fertilizer in wheat basal fertilizer or the lack of phosphorus in soil often causes yellowing of phosphorus in wheat. Field performance was as follows: very few secondary roots, few tillers, dark green leaves, and yellow tips. Phosphorus yellowing in wheat will lead to less spikelets and a decrease in grain weight, seriously affecting yield. When wheat seedlings are deficient in phosphorus, 10 kg of diammonium phosphate or 45-50 kg of superphosphate can be applied per acre. 4. The sowing density of wheat is too large. The high density of wheat sown causes the wheat population to be too large, which affects the photosynthesis of wheat and causes insufficient supply of nutrients, resulting in yellowing of the leaves. Therefore, it should be sown according to the season and temperature. 5. Sustained cold damage by freezing. Sustained low temperature, less light, wheat as a whole is weak, affected by the low-temperature freezing show yellow. The prevention and control measures were to strengthen management and spray foliar fertilizer after the arrival of the cold spell. 6. Causes of pests and diseases. The main wheat diseases are sheath blight, total erosion and root rot. All of them are fungal diseases. They can show yellow leaves at the early stage of development, but the site of lesions and the shape of lesions are different. Sheath blight is mainly harmful to leaf sheath; full-blown disease mainly damages stem base and root; root rot only occurs in roots. All of them rely on soil-borne diseases. Tebuconazole and propiconazole can treat these three diseases simultaneously. Underground pests can also harm wheat and cause yellow leaves. The control method is chemical seed dressing and soil treatment. Puyang Linshi Medical Supplies Co., Ltd. , https://www.linshimedicals.com