Some effects of straw residues and cultivation system on tillering in winter wheat

Straw residues can reduce the yield of a following cereal crop, perhaps through an effect on tillering. Over two years we measured tillering of winter wheat on a clay soil where straw was either burnt or chopped and returned. Seed was direct drilled in the first year and direct drilling was compared with conventional sowing after ploughing in the second year. Straw had no marked effect on the production per plant of the first three main tillers. Direct drilling resulted in earlier tillering and more tillers per plant than conventional sowing after ploughing, but this was not reflected in grain yields calculated from components of yield. Part of the tillering effect may have been caused by differences in sowing depth.