First, the harm of wheat sowing too deep
1, the emergence of wheat will be affected. If the seed vigor is not strong, it will break through the ground because the seed is too high from the surface, resulting in seedling shortage.
2. The seedling stage is weak. Because of sowing too deep, wheat will consume too much nutrients when it emerges, so it will appear pale yellow when it grows at seedling stage.
3. Reduce tillering. In the plots sown too deeply, the emergence time of normal wheat is late, and there will be fewer tillers in the later stage.
2. Remedies
1, water and fertilizer
If it is a plot with good soil moisture, although it will emerge in a few days, if foliar fertilizer is sprayed in time to supplement the nutrients consumed during emergence, it will not have much impact. However, if it is a community with poor soil moisture, it can be watered in the soil, but it should be noted that the amount of water should not be too large, which can promote the growth of seedlings, improve the germination rate of seeds and make germination successful.
Step 2 Rake the soil
In the past, many farmers would use this method to spread soil on the surface of the sown land with bamboo harrows or other tools to artificially reduce the planting depth, but this method consumes a lot of labor and is not suitable for large-scale planting.
Step 3 replay in time
When it is found that there is a lack of seedlings in wheat seedling stage, it is necessary to replant them in time and sow them as shallow as possible, so that the wheat seedling stage can grow vigorously as soon as possible.
Causes of weak yellow of wheat seedlings
1. The straw returned to the field is very shallow.
Returning the harvested corn stalks to the field and sowing wheat not only conforms to the law of agricultural production, but also improves soil fertility and avoids the pollution caused by burning corn stalks. However, at present, the number of corn returned to the field and the tillage layer are generally below 20 cm, which makes part of the back roots of wheat trapped on the surface of straw, and it is difficult to absorb nutrients from the soil. Moreover, many people do not have the habit of surface treatment of wheat seedlings, and it is inevitable that fragile seedlings will turn yellow again. Therefore, when corn stalks are returned to the field, they must be chopped and then pressed to keep the soil moisture, so as to avoid hollowing and directly affect the nutrition of wheat seedlings, and nitrogen fertilizer should be applied in time.
2. Continuous low temperature and freezing injury
In the low temperature period of winter wheat planting, if the climate changes greatly at this stage, such as more rainy days, continuous low temperature and less light time. The overall seedling raising conditions of wheat are weak, and the leaves will turn yellow directly due to the influence of low temperature and freezing injury. Therefore, it is necessary to strengthen management and spray foliar fertilizer before the arrival of cold to avoid the harm of low temperature to yellow seedlings.
3. Lack of fertilizer
In the process of wheat growth, if sowing is too early, the base fertilizer is insufficient or the nitrogen content in the base fertilizer is low, it will also lead to the shortage of wheat flavin nitrogen. When the phosphorus in wheat base fertilizer is insufficient or the soil is short of phosphorus, it will also lead to phosphorus deficiency and yellowing of wheat, which is characterized by less secondary roots, less tillers, dark green leaves and yellowing of tip. Nitrogen deficiency requires timely topdressing of 5 kg urea per mu, and topdressing of urea 10- 15 kg per mu in the extended period; In case of phosphorus deficiency, 10 kg diammonium phosphate or 45-50 kg calcium superphosphate can be applied per mu. If the soil is acidified, the fertilizer should be carefully selected. It is suggested to use plant ash or quicklime to improve soil.
4. Sowing too deep
Generally speaking, the suitable depth of wheat sowing is 3-5 cm. Sowing too deep, even if the wheat seedlings come, if the climate is dry, the seedlings will grow weak, turn yellow and tiller less. If it is rainy, the situation will be more serious, resulting in a large area of withered seedlings. For plots with mild illness, it is necessary to buy spraying in time, not only to make seedlings take root and thrive, but also to disinfect them, and to quickly replant some dead fields.