Residual effects of faba bean and soybean for a second or third succeeding forage-corn production

Abstract

Many studies have been conducted on the effects of annual legumes on subsequent corn production but they rarely extended beyond a second succeeding crop. We have therefore conducted field experiments on a sandy gravelly loam at St-Anselme and on a silty loam at Deschambault in eastern Quebec to determine the residual effects of (i) faba bean (Vicia faba L.) and soybean (Glycine max [L.] Merr.) on a third succeeding corn (Zea mays L.) crop and (ii) 2 consecutive years of these legumes on a second subsequent corn crop. In monoculture or following legumes, corn was fertilized with 0, 50, 100 or 150 kg N ha−1 as NH4NO3. The corn stover and whole-plant dry matter yields (DMY), and the ear and whole-plant N uptake were higher following faba bean grown 3 years earlier than in monoculture at both locations. At Deschambault, the stover DMY of second subsequent corn following 2 consecutive years of faba bean did not vary with the N application. At both locations, the DMY, N concentrations and N uptake of second subsequent corn were higher after 2 consecutive years of faba bean than after other previous crop sequences. Two consecutive years of soybean had significant effects on the DMY and N uptake of a second subsequent corn crop with N application at Deschambault. At both locations, the N-fertilizer replacement values (NFRV) of soybean were lower or equal to 0 kg N ha−1. The NFRV (DMY and N uptake bases) of faba bean grown three years earlier and of 2 consecutive years of this pulse varied widely between locations. Key words: Corn, faba bean, soybean, residual N, crop sequence, rotation effects