Conversion Strategies for Stockless Organic Systems

D.L. SPARKES, S.K. HUXHAM and P. WILSON
University Of Nottingham, Sutton
Bonington Campus Loughborough, Leicestershire, LE12 5RD, UK

Abstract
Legume-containing leys are used to improve soil fertility in the two-year organic conversion period. While in-conversion land may be grazed, it is effectively out of production in stockless farming systems, potentially resulting in a reduction in income and pressure on cash flow.

The effects of seven conversion strategies on a subsequent organic winter wheat crop were investigated on a sandy loam and a clay loam soil. The strategies were: 1) two-years’ red clover-ryegrass green manure; 2) two years’ hairy vetch green manure; 3) red clover for seed production then a red clover-ryegrass green manure; 4) spring wheat undersown with red clover, then a red clover green manure; 5) spring wheat, then winter beans; 6) spring oats, then winter beans; and 7) spring wheat undersown with red clover, then a barley-pea intercrop.

Conversion strategies had a significant impact on organic wheat yield, which ranged from 2.8 to 5.3 t/ha. This was attributed to differences in organic wheat establishment, caused by variation in soil structure due to the different conversion strategies. Organic wheat yield was not related to weed abundance or soil mineral nitrogen.

Source
Symposium No. 37 Proceedings, British Grassland Society, 2004
Institute of Grassland and Environmental Research
North Wyke, Okehampton, Devon, EX20 2SB, UK
Association of Applied Biologist & Colloquium of Organic Researchers

Posted March 2008