EFFECTS OF FORAGE LEGUME SPECIES ON SOIL MOISTURE, NITROGEN, AND YIELD OF SUCCEEDING BARLEY CROPS

Abstract

Effects of five legume species grown for hay on yield of succeeding barley crops and on moisture and N status of five soils were measured. When N fertilizer was applied, yields of barley following alfalfa, birdsfoot trefoil, alsike clover, red clover and sweet clover were the same as those following barley grown on fallow (control). Also, soil moisture in spring and soil moisture used by barley were about the same following legumes and the control. However, without N fertilizer, the legumes caused large yield increases to barley grown on two Gray Luvisolic soils (Beryl, Davis) and a Black Solodic soil (Landry); the legumes caused little change in barley yields on another Gray Luvisolic soil (Alcan) and caused large decreases on another Black Solodic soil (Rycroft). Residual soil N contributed by the legumes, calculated from N in the succeeding barley crops, was greater for the Beryl and Landry soils than for the Alcan and Davis soils. This corresponded closely to yields of the previous hay crops on those soils. The legumes caused a decrease in residual N for the Rycroft soil. Mineral-N and Δ mineral-N in the soil were well correlated with N uptake in barley for the Alcan, Landry and Rycroft soils but were poorly correlated for the other two soils. Key words: Forage legumes, barley yields, soil nitrogen and moisture