When is the right time to water wheat for the green-up stage?

AbstractWheat generally in late March of spring, when the daily average temperature reaches above 3°C, according to soil moisture conditions and wheat growth conditions, water for the green-up stage. Watering is generally best done with a small amount of water, and flood irrigation must not be used during this period. For wheat with weak growth, an appropriate amount of green-up water may be applied, and 15-20 jin of urea and 10-15 jin of potassium sulfate or potassium chloride per mu may be applied as a topdressing to promote tillering of wheat in early spring, thereby improving wheat quality and yield.

I. Time for watering wheat for the green-up stage

1. Generally in late March of spring, when the daily average temperature reaches above 3°C, it is relatively suitable to water winter wheat for the green-up stage. As temperatures begin to warm up, winter wheat vernalization quickly enters the green-up stage. Temperature is the main factor affecting the green-up of winter wheat. In winter, suppression is beneficial for preserving moisture, heat, and fertilizer, and can better prevent freezing and protect seedlings, control upward growth and promote downward growth, making the wheat rhizomes solid and the seedlings grow robustly.

2. Green-up water needs to follow the principles of being scientific, reasonable, and appropriate in amount. If fertilizer and water are applied too early, it will cause excessive tillering of spring wheat, resulting in an oversized population, and will also cause nutrient waste, laying hidden dangers for later lodging and pests and diseases in wheat.

II. Methods and precautions for watering wheat for the green-up stage

1. Water for the green-up stage according to soil moisture conditions

(1) Generally, wheat fields that were sown by grabbing moisture before winter and were not given winter irrigation, have poor tillage quality, and have severe moisture loss in the field, as well as wheat fields with poor individual wheat development, small populations, and severe drought, all need timely green-up water. The time for watering green-up water is generally most suitable when the daily average temperature reaches above 3°C.

(2) Generally, as long as the soil moisture in the wheat field is good, green-up water should be delayed or not applied, and the green-up water can be postponed until the standing-up or jointing stage. For wheat fields with small populations, poor growth, excessive growth before winter, and weak growth in spring, 20 jin of urea per mu may be applied as a topdressing along with watering. After watering, when the soil moisture in the wheat field is relatively suitable, timely hoeing should be carried out to preserve moisture.

2. Strictly control the amount of green-up water

Because the temperature difference between day and night in early spring is relatively large, and cold and warm air currents alternate frequently, the watering amount is generally best kept small. Flood irrigation must absolutely not be used, to prevent freezing damage to wheat caused by excessively low air and ground temperatures when a cold wave occurs.

3. Water for the green-up stage according to seedling conditions

(1) In wheat fields sown at the appropriate time before winter, insufficient soil fertility will lead to fewer wheat tillers. Generally, when the total number of stems per mu before winter is around 500,000, green-up water may be applied appropriately. During this period, along with watering, 15-20 jin of urea and 10-15 jin of potassium sulfate or potassium chloride per mu may be applied as a topdressing, thereby promoting tillering of wheat in early spring.

(2) For late-sown wheat and strong seedlings with a total stem number of 700,000-900,000, as well as overly vigorous seedlings with more than 900,000, fertilizer and water are sufficient and green-up water may not be applied. During this period, intertillage and loosening of the soil may be carried out to preserve moisture and increase temperature, and it is best to suppress spring tillering to a relatively low level. For wheat fields with excessive growth before winter, because the large growth amount consumes more fertilizer and water, and winter irrigation was not carried out, resulting in poor soil moisture in the field, and because encountering a late spring cold in early spring can easily cause seedling death, timely green-up water is also needed.