Management techniques of late wheat in early spring

Due to heavy rainfall during the sowing period before and after the "National Day" last year, wheat farmers were sown only after the cold dew solar term, forming late wheat; in addition, the rainfall at that time also delayed the growth of wheat sown at normal time, also forming late wheat. As a result, more than half of the 1.1 million mu of wheat sown last year in this city are late wheat. The growth characteristics of late wheat are different from those of common wheat, so the early spring management techniques are also different.

Late wheat generally refers to wheat sown after the Cold Dew Festival. Its growth characteristics are different from those of wheat sown at appropriate time, mainly as follows: small overwintering seedling age, few tillers, few secondary roots and short stems in the ground. The root group construction period of late wheat was mainly in the green stage. The main causes of late wheat yield reduction in production are as follows: 1. insufficient ears per mu; 2. insufficient phosphorus fertilizer, resulting in small old seedlings; 3. late sowing and early tube management in early spring, watering early, watering and fertilizing more. Due to excessive moisture in the re-greening stage, it often causes cold, soil plate and alkali return, which is unfavorable for root development, delays wheat growth, leads to late heading, and low grain weight in late stage due to high temperature. Therefore, the early spring management of late wheat mainly focuses on improving ground temperature, preserving moisture and aerating, and promoting early seedling development.

1. Soil removal. Dewatering after watering or rain to conserve soil moisture. This is the main management measure of water-saving and drought-resistance of early spring wheat.

2. Topdressing fertilizer, especially phosphate fertilizer. Because of the low temperature in early spring, the weak phosphorus supply capacity of soil, at the same time, the small root group of wheat and the weak phosphorus absorption capacity, the late wheat is more sensitive to phosphorus in early spring. If the phosphorus fertilizer is insufficient, it is easy to form small old seedlings, resulting in the yield reduction of late wheat. Generally, the yield per mu of late wheat is more than 400 kg, and the appropriate amount of nitrogen, phosphorus and potassium fertilizer for the whole growth period is 35 kg urea, 25 kg diammonium phosphate and 15 kg potassium sulfate per mu. And 60% of total nitrogen and all phosphorus and potassium fertilizer are applied as base fertilizer. For the wheat field with insufficient base fertilizer, the top dressing method can be used to supplement the insufficient part before the early spring soil is cleared.

3. Postponing spring fertilization and watering. For the wheat field with sufficient soil moisture and timely winter irrigation before winter, the suitable watering time of late wheat can be grasped. The standard is that new tillers (latent tillers) are exposed, new roots grow about 1.5 cm, and panicle differentiation enters the two-edge stage. The approximate time is in the middle of early April. Combined with watering, 40% of the total nitrogen fertilizer amount is applied. If the soil moisture is insufficient, according to the wheat seedling growth situation, appropriate early tube.

4. Fall prevention and weeding. Because the sowing quantity of late wheat is relatively large and the root group is small in early spring, if the management is not good, it is easy to lodge, so attention should be paid to preventing lodging and weeding from getting up to jointing stage.