“Wheat in two stages of vigorous growth”—how can we prevent excessive vegetative growth before winter?

As the saying goes, “Wheat that grows too vigorously before winter is undesirable.” Excessive vegetative growth in wheat prior to winter can advance the reproductive phase, reduce nutrient accumulation, and weaken cold tolerance, thereby jeopardizing its ability to overwinter safely. So, what should be done about excessive pre-winter growth in wheat? And how can such overgrowth be prevented?

Types of Vigorous Wheat Seedlings Before Winter and Management Practices

Sowing too early results in weak seedlings with narrow, drooping leaves and insufficient tillering; the main stem and some of the larger tillers enter the two‑ridge stage of spikelet differentiation before winter. Such vigorously growing seedlings often exhibit a pattern of initial vigor followed by weakness, making them susceptible to frost damage when exposed to temperatures around –10°C for about five hours during winter. Management measures: apply rolling at the appropriate time. Rolling suppresses the growth of the main stem and large tillers, thereby controlling excessive elongation. When rolling, choose a clear day; avoid rolling on mornings when frost or dew remains wet, as this can injure the seedlings. Following rolling, promptly hoe the field and, in conjunction with irrigation, apply 15 kg of ammonium bicarbonate per mu. If necessary, foliar spray with a 0.2%–0.3% solution of chlormequat chloride to further curb excessive growth and enhance frost resistance.

Excessive seeding density results in vigorous seedlings that grow densely packed, with poor individual development and very limited tillering. Management measures: first, thin the seedlings promptly to establish an appropriate stand structure and promote individual growth; then, combine this with irrigation and apply an appropriate amount of quick‑acting nitrogen and phosphorus fertilizers to offset the excessive depletion of soil nutrients.

Excessive irrigation has resulted in vigorous wheat seedlings with abundant tillers and broad, large leaves, leading to severe canopy closure in the field. Management practice: deep hoeing to sever roots. When the main stem of the wheat seedlings has developed five leaves, perform a deep hoeing 5–7 cm between the rows to cut off some secondary roots, thereby restricting nutrient uptake, reducing tillering, and promoting the development of robust seedlings.

Improper variety selection. For certain spring‑type and weakly winter‑hardy varieties, sowing too early can also result in vigorous growth before winter. Such overly vigorous seedlings are particularly susceptible to frost damage during the winter. Management measures: In addition to timely hoeing and rolling, mound soil around the base of the plants before winter or apply a “covering manure” layer to help the wheat seedlings overwinter safely.

How to prevent excessive vegetative growth in wheat before winter

1. Rolling the wheat: Rolling helps control above‑ground growth, promotes root development, strengthens vigorous seedlings, and prevents premature stem elongation. However, when rolling, take the following precautions: do not roll fields that are excessively wet, overly dry, or compacted; avoid rolling if the seedlings are too weak; and refrain from rolling after frost damage. Additionally, roll robust seedlings but not tender ones, and favor vigorous seedlings over weak ones; vigorous seedlings can be rolled repeatedly.

2. Soil Covering for Wheat: This involves covering the wheat with fertile soil or nutrient-rich organic waste. Such covering suppresses ineffective tillering, controls excessive vegetative growth, strengthens stems to prevent lodging, and simultaneously promotes soil buildup around the base of the plant, provides insulation against frost, and conserves moisture and nutrients. It also enhances the wheat’s nutrient‑absorbing capacity, delays premature senescence, ensures clean, well‑formed root collars, improves ventilation and light penetration, produces uniform ear development, and facilitates consistent maturity—conditions that favor large, well‑filled ears and high yields. Soil covering is typically carried out from late December to early January. Vigorous seedlings should be covered first and more heavily, while weaker ones should be covered later and more lightly. Avoid covering on overcast, rainy days or when dew has not yet dried, as this can lead to “wet covering” and rotting of the seedlings. In addition, the soil must be finely textured, applied evenly, and maintained at a consistent thickness (about 1–2 cm), ensuring that the roots are fully buried, the stubble remains upright, and the leaves remain exposed.

3. Deep and medium tillage: By performing deep and medium tillage, part of the plant’s root system is severed, thereby weakening its ability to absorb nutrients and suppressing above‑ground growth. However, the tillage must reach a sufficient depth and involve root cutting; if only shallow tillage is carried out without severing the roots, it will not effectively control excessive vegetative growth. Moreover, loosening the soil and improving root‑zone conditions may inadvertently promote vigorous seedling growth. The timing of root‑cutting during tillage should not be too late—this work should be completed about 20 days before winter—to allow the root system to recover promptly and ensure successful overwintering.