What causes weak and yellow wheat seedlings?
Many growers know that weak and yellow wheat seedlings are extremely common, and in some areas severe cases can even lead to large-scale death of wheat seedlings, causing huge economic losses to growers. So what causes weak and yellow wheat seedlings? Follow along with the editor to learn about it.
1. Straw returned to the field and shallow plough layer
After the corn harvest, returning its straw to the field before sowing wheat not only conforms to agricultural production practices but also improves soil fertility and avoids the pollution caused by burning straw, achieving three benefits at once. However, the amount of corn straw returned to the field is now large, and the plough layer generally does not exceed 20 cm, so after some wheat seedlings emerge their root systems rest on the straw, making it difficult for them to absorb nutrients from the soil. Many people also do not have the habit of topdressing at the wheat seedling stage, so weak and yellow seedlings are unavoidable. Therefore, when returning corn straw to the field, it must be chopped and then pressed to preserve soil moisture, so as to avoid hollow spaces that directly affect the nutrition of the wheat seedlings, and nitrogen fertilizer should be applied in time as a supplement.
2. Continuous low-temperature freezing damage
When planting winter wheat, this occurs during the low-temperature period. If the climate changes greatly during this stage, such as consecutive days of rain, continuous low temperatures and little sunshine, the overall condition of the wheat seedlings is relatively weak, and the effects of low-temperature freezing damage will directly show as yellow leaves. Therefore, management should be strengthened before the cold wave arrives, and foliar fertilizer should be sprayed to prevent yellowing of seedlings caused by low-temperature freezing damage.
3. Fertilizer deficiency
During the growth of wheat, if sowing is too early, the base fertilizer is insufficient, or the nitrogen content in the base fertilizer is low, it can also cause nitrogen-deficiency yellowing in wheat. When phosphate fertilizer in the wheat base fertilizer is insufficient or the soil is deficient in phosphorus, it can also cause phosphorus-deficiency yellowing in wheat, manifested as very few secondary roots, few tillers, dark green leaf color and yellow leaf tips. For nitrogen deficiency, apply 5 kg of urea per mu in time as a topdressing, and at the jointing stage after the standing period apply another 10-15 kg of urea per mu as a topdressing; for phosphorus deficiency, apply 10 kg of diammonium phosphate or 45-50 kg of superphosphate per mu as a topdressing. If the soil is acidified, chemical fertilizers should be chosen carefully, and it is recommended to use plant ash or quicklime to improve the soil.
4. Sowing too deep
Under normal circumstances, the suitable sowing depth for wheat is 3-5 cm. If sown too deep, then even if the wheat emerges, the seedlings will be poor. If the climate is dry, then the seedlings that grow will be weak, yellow and have few tillers; and if it is rainy, the situation will be even more serious, causing large-scale seedling death. For plots with mild symptoms, buy medicine promptly and spray it, both to promote rooting and strengthen seedlings and to sterilize, while for plots with partial death, replant as soon as possible.
The above is an introduction to what causes weak and yellow wheat seedlings. We hope it can help you. To learn more related knowledge, please keep following us.