Production of organic wheat: Trials on varieties, seed rate, weed control and the use of permitted products

Abstract

The organic wheat production area is continuing to expand but it is still far from supplying the needs of the end users in the UK. Current estimates of 50% of organic breadmaking wheat and 80% of feed wheat for animal feed being imported indicate the potential for continued expansion of the UK production of organic wheat grain.

Variety selection could be considered an even more important decision in the organic sector compared to the conventional sector and the three seasons of variety trials described in this project emphasise the need for great care when selecting wheat varieties for organic production. Traditionally organic growers would take much of their guidance from variety performance in conventionally grown trials but this project questions the wisdom of that strategy.

Varieties such as Hereward and Exsept perform well in organic situations but some of the more traditional high yielding varieties like Savannah and Consort have done less well. It appears that to fully evaluate the performance of a variety for its suitability for organic production it should be tested in an organic situation,. Extrapolation from conventional trials may be useful but will not precisely define the most suitable varieties for organic production situations.

It would also appear that organic growers may not be able to follow the current trend in the conventional wheat production sector to reduce seed rates. Lowering seedrates was consistently associated with lower yields in this three season trials series.

In the quest for higher grain protein content growers in the organic sector have explored the value of products that contain seaweed extracts applied to crops. In the three seasons when seaweed extract products (and concentrated manure products) were applied to organic wheat crops no significant increases in yield were recorded. Some increases in grain protein content did result from treatment, up to 1.03% in one trial, but the economic value of this is uncertain unless the growers has a contract that is adjusted financially for protein content.

A more interesting potential input is sulphur. In view of the decreasing availability of sulphur to all crops as a result of lower sulphur deposition levels from the atmosphere, it was extremely interesting to find in the 2001 trials a significant increase in grain yield, up to 10%, as a result of a foliar application of sulphur. Sulphur deficiency is increasing in incidence in conventional crops and this trend may also be developing in organic wheat crops.

It is important that the value of sulphur to organic breadmaking wheat crops is more extensively evaluated and that techniques to select varieties for organic production are conducted in organic situations.