What to do when wheat seedlings are weak and sparse? Apply fertilizer in time to promote tillering

After wheat begins tillering, the number of tillers increases continuously with the growth and development of the plant, and the total number of stems and tillers reaches its maximum around jointing. After that, the later-emerging tillers die off one after another due to insufficient nutrients and other reasons, and the number of stems and tillers becomes basically stable only after heading. Generally, after a tiller emerges, it first relies on the main stem and large tillers to supply nutrients; after the first green leaf appears, it begins to produce nutrients, and at the same time it also relies on large tillers and the main stem to supply nutrients, and only finally does it absorb and produce nutrients on its own. Under normal circumstances, when wheat begins jointing, only tillers with more than 3 functional leaves and an independent root system have the possibility of forming ears. When field density is too high, large tillers with more than 3 leaves at wheat jointing often cannot form ears either. Tillers that ultimately cannot form ears are all ineffective tillers.

The occurrence of wheat tillering maintains an n-3 synchronous relationship with the leaf age of the main stem, that is, when the main stem has 3 leaves, tillers occur at the coleoptile node; when the main stem has 4 leaves, tillers occur at the first leaf node; when the main stem has 5 leaves, tillers occur at the tiller sheath node of the coleoptile node tiller and at the second leaf node of the main stem. The key focus of management during the wheat tillering stage is to promote roots and increase tillers, cultivate early-developing strong seedlings, ensure that wheat seedlings overwinter safely, and lay the foundation for sufficient ears and large ears. The wheat in the above field has just begun tillering, the wheat seedlings are somewhat weak in growth, and the number of seedlings is not large. At this time, providing sufficient fertilizer can promote early and rapid tillering, increase the rate of tillers forming ears, and promote young ear differentiation. If fertilizer supply is insufficient at this time, the wheat seedlings may become even thinner and weaker, with insufficient tillering, leading to an increase in ineffective tillers after winter, fewer effective ears, and low yield.

The soil was dry some time ago, so attention should be paid to management according to the earlier fertilizer amount and changes in soil moisture. For fields with sufficient base fertilizer and earlier soil drought, when soil moisture increases after recent rainfall, the wheat seedlings can absorb more nutrients, so there is no need to rush to fertilize. For fields with insufficient base fertilizer and seedling fertilizer, fertilizer should be applied early. Generally, apply 10 kg of urea or 20-25 kg of ammonium bicarbonate and 5 kg of potassium chloride per mu. Pay attention to irrigation for drought resistance to promote wheat seedling growth. Combined with fertilization, use furrow irrigation, irrigating water to two-thirds of the furrow depth, allowing water to penetrate and moisten the soil, and preventing flooding irrigation and long-term water accumulation in the field.