Repeated undersowing of clover in stockless organic grain production

Summary

There is a need for better knowledge of the production potential in organic stockless cereal production systems, and especially how legumes may be used most efficiently in the crop rotation. Field experiments were carried out during 2002-2005 to study biomass production, weed regulation effects, nutrient uptake and cereal yields at two experimental sites. Undersowing of clover is a common practice among organic cereal producers. Hence, crop rotations with four years of continuous undersowing (oats + red clover/wheat + white clover) were compared to rotations where the second year was a green manure ley. The average annual grain yields in the four year period were 25% higher with clover undersowing than in treatments without undersowing, but only 5% higher in rotations with one green manure year. Hence, the current practice of organic cereal producers seems relevant.