Pressure on the financial margins in cereal production are immense. Many businesses have taken vital steps to reduce the fixed costs by cutting back on labour and machinery, or by farming larger areas.

However, we must also recognise that each crop on the farm must produce the maximum financial output for the minimum input if growers are to remain competitive. Minimising inputs whilst maintaining or increasing output requires a great deal of care. A better understanding of how crops produce their yield helps growers to target inputs more accurately.

Wheat Growth

and Development

A large amount of work done in the 1990s funded by the Home Grown Cereals Authority (HGCA) and the Ministry of Agriculture, Fisheries and Food (MAFF) has improved our understanding of wheat physiology. The work has identified the main growth phases of the crop and when they 'switch' on or off according to the development stage of the crop.

Old ideas that growing crops as large as possible to produce maximum yield relied on the principle that the ratio between total crop growth and grain yield (harvest index) is relatively stable. This recent work has shown this to be largely untrue.

We now have a much better understanding of which phases are likely to be limiting and which phases are likely to have little effect on final yield. Using this knowledge allows us to minimise input costs without reducing yield potential.

Managing the

crop canopy

As crop managers our main aim must be to ensure that growth during June and July is maximal, as this is when the yield is produced. But also that the early growth phases of the crop are sufficient to provide a large enough canopy to intercept the incident light during grain fill, and sufficient grains to produce the yield.

To do less than this will reduce yield but to do more is wasteful of resources and inputs and crop may require additional growth regulators and fungicides.

Research results show that increasing the maximum canopy size of a crop (which occurs at ear emergence) above a green area index of six provides no measurable benefits in terms of light interception. Any increase above this is simply a waste of nitrogen.

Reducing seed costs

One area to benefit from this research is seed costs. We have found that we can exploit the compensatory abilities of the crop to reduce costs. Crops sown at standard populations frequently produce in excess of 1000 shoots/m2 at the start of stem extension and maintain up to 600 at harvest.

However, low plant populations do not just exploit the over production of shoots. Crops grown at low densities produce more tillers per plant, have larger shoots and use light more efficiently.

Despite the total ear number being lower, ears are larger and the number of grains per ear is higher thus maintaining yield.

Are growers reducing rates?

In practice growers are generally taking a cautious approach. The Rosemaund farmers association (RFA) a farmers group managed by ADAS Rosemaund, visited two farms this spring at Breinton and Lienthall Earls where seed rates have been reduced to around 200 seeds/m2 for end of September / early October plantings. On Both farms the crops looked well and were slightly ahead of the benchmarks for shoot numbers and green area indices laid down in the wheat growth guide.

The focus of research at Rosemaund is to improve decision making to minimise inputs whilst maintaining or increasing yield. Current projects include an extension of the work on wheat. Other work is focused on applying the same principles to oilseed rape, oats and barley production.

The Rosemaund open day is on Thursday 27th June between 2pm and 8pm, Admission is free, with a bar and BBQ on site.

Comparisons of Jockey and Latitude take all seed dressings, work on naked oats, and disease control in wheat are also being demonstrated. The HGCA will also be demonstrating work on sulphur, management strategies for early sown wheat, canopy management in oilseed rape and seed rates in wheat.

ADAS consultants specialising in the woodland and conservation grants will also be available to provide advice on making an application to join the Farm Woodland Premium Scheme, and Countryside Stewardship Scheme - which now includes a range of arable options.

Farmers interested in receiving further advice can request a DEFRA funded visit from an ADAS consultant.

For further information call Jonathan Blake on 01432 820444.