Seed yield and residue production of lentil cultivars grown at different slope positions

The presence of crop residue on the soil surface is important in controlling soil erosion, but residue amounts from lentil (Lens culinaris Medik) are often insufficient to control soil erosion during subsequent phases of the cereal-grain legume cropping systems of the U.S, Pacific Northwest. To gain knowledge of residue production by lentil in typical production environments, six lentil cultivars were grown at four slope positions in southeastern Washington over 3 yr. Residue and seed production varied significantly among cultivars and slope positions (P < 0.01), Total residue production ranged from four to 20 times the 290 lb/acre required by conservation standards, however, the amount remaining after sowing of the subsequent winter wheat (Triticum aestivum L.) crop was much less, indicating that large losses occurred during harvesting and tillage operations, On lower slope positions, grain and residue yields were inversely correlated for all cultivars. On upper slope positions, grain yields were nearly constant among cultivars, but 'Laird' produced an average of 42% more residue than 'Brewer', No single cultivar met yield and residue production criteria across all landscape positions, Growers can improve erosion control by site-specific sowing of high-residue cultivars such as Laird. Breeding programs should consider the differences in the upper and lower slope positions for seed and residue production when selecting for cultivars with improved biomass production.