What causes weak and yellow wheat seedlings
Many growers know that weak and yellow wheat seedlings are extremely common, and in severe cases in some areas they can even cause large areas of wheat seedlings to die, resulting in huge economic losses for growers. So what causes weak and yellow wheat seedlings? Let's find out together.
1. Straw returning to the field and shallow tillage layer
After the corn harvest, returning its straw to the field and then 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 tillage layer generally does not exceed 20 cm, so after some wheat emerges, its roots sit on the straw, making it difficult 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 compacted to preserve soil moisture, so as to avoid hollow spaces that directly affect wheat seedling nutrition, and nitrogen fertilizer should be applied in time as a supplement.
2. Continuous low-temperature freezing damage
When planting winter wheat, during the low-temperature period, if the climate changes greatly at this stage, such as consecutive days of rain, continuous low temperatures, and little sunshine, the overall wheat seedling condition is relatively weak, and the effects of low-temperature freezing damage directly appear as yellow leaves. Therefore, management should be strengthened before the cold wave arrives, and foliar fertilizer should be sprayed to prevent yellow seedlings caused by low-temperature freezing damage.
3. Fertilizer deficiency
During wheat growth, if sowing is too early, base fertilizer is insufficient, or the nitrogen content in the base fertilizer is low, wheat can also develop nitrogen-deficiency yellowing. When the phosphorus fertilizer in the wheat base fertilizer is insufficient or the soil is phosphorus-deficient, wheat can also develop phosphorus-deficiency yellowing, 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, and at the jointing stage after green-up apply another 10-15 kg of urea per mu; for phosphorus deficiency, apply 10 kg of diammonium phosphate or 45-50 kg of superphosphate per mu. 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 sowing is too deep, then even if the wheat emerges, the seedlings will be poor. If the climate is dry, the seedlings that grow will be weak, yellow, and have few tillers; if it is rainy, the situation will be even more serious and cause large areas of dead seedlings. For plots with mild incidence, buy medicine and spray it in time, both to promote rooting and strengthen seedlings and to sterilize; 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. If you want to learn more related knowledge, please follow us.