Crop support: Time to build on firm footings 

With many winter cereals looking to have established well last autumn, Hutchinsons technical support manager, Neil Watson, explains how to support and build on this promising start heading into spring. 

 It remains to be seen what the weather will hold this season, so all we can do is reinforce this good start and give crops the best chance of fulfilling their promising potential this harvest. 

Assess potential 

As crops emerge out of winter, it is worth assessing their potential by examining root development and above ground growth. Assess how many plants/m² you have, how many tillers per plant, the size and condition of those tillers, and whether they will realistically come to anything. 

Wheat often produces a main tiller and several smaller ones, many of which (up to 40%) can be dropped by GS 31–32. 

Also identify your target number of tillers (and therefore ears) to take through to harvest. The number of ears per plant can be smaller than you might expect, so be realistic about what individual crops and fields can achieve. 

The AHDB Wheat Growth Guide has a benchmark of 460 ears/m² and 48 grains/ear for an 11t/ha crop, with some of the biggest crops carrying 700–800 ears/m² to harvest. 

Support root development 

Phosphite-based biostimulants have been shown to help stimulate root growth, and therefore subsequent tiller retention, as well as enhancing the effects of plant growth regulators (PGRs). 

Phosphites should be used early in the season though, typically at GS 30, although there may be some benefit up to GS 31. 

Optimise biomass accumulation 

Yield is all about biomass accumulation and what proportion of that biomass goes into producing grain; the harvest index. 

Water, light and nutrients are three of the biggest factors influencing biomass growth, so as well as having a good root system, crops need to be kept free from disease to maximise photosynthetic capacity, supplied with adequate nutrition at the right times, and have strong, even tillers to stay standing through to harvest. 

Manipulate growth, support tillers 

Experience shows that an early application of a PGR, such as trinexapac-ethyl or chlormequat, at GS 30 (T0) can help manipulate plant growth and promote the retention of more tillers of an even size and good yield potential. 

It works by controlling the apical dominance in the plant to help balance the flow of nutrients and energy across the leaves, stems and developing spikelets. This gives plants the best chance of retaining as many tillers as they can support, with strong stems and large ears. 

Feed potential 

As growth gets underway in early spring and crops begin to move from the foundation to construction phase, it is vital to ensure they have adequate nutrition, with nitrogen being central to tiller survival. 

Generally, nitrogen applied during stem extension encourages both canopy expansion and tiller survival, with later (post-stem extension) nitrogen promoting canopy survival through to grain fill, and increasing grain protein. 

Extra care may be needed with early nitrogen management this spring, especially where there is higher residual soil nitrogen left from last season. Excess nitrogen can result in more soft, sappy growth, that may be more prone to lodging and infection from biotrophic diseases such as rust or mildew, so target fertiliser applications carefully. 

Address variability  

Aerial or satellite imagery, such as that available through Omnia, can be a useful tool to help monitor changes in crop biomass and identify any areas that are not progressing as much as others. 

There are recognised benchmarks for biomass accumulation by certain growth stages, which can be used alongside actual measurements from the field, to identify any areas that warrant closer inspection, and target necessary management actions.

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