The Korean Journal of Crop Science ISSN:0252-9777(Print) 2287-8432(Online) 한국작물학회지

Green manure has been used as alternative to chemical fertilizer. To evaluate the effect of green manure on the chemical properties of top-soil and sorghum yield, hairy vetch (Vicia villosa Roth, HV), manure barley (MB), and a mixture of hairy vetch and manure barley (HV+MB) were incorporated into the soil at a rate of 100 kg-N N ha^-1 before the sorghum was transplanted. Total biomass of sorghum grown in the HV, MB, and HV+MB treatments was 13.1, 31.6, and 25.2 t ha^-1, respectively, and the nitrogen production of the treatments was 81, 74, and 145 ㎏ ha^-1, respectively. The SPAD value of the uppermost leaf of sorghum plants grown in the soils with HV, MB, or HV+MB were very similar until heading stage; however, at maturity, the SPAD value of sorghum cultivated in the soils with HV was lower than that of sorghum in the soils with MB or HV+MB. This could be because the nitrogen release from HV was too rapid to supply nitrogen to sorghum during the later stage of grain filling. Compared with chemical fertilizers, the incorporation of green manure increased the pH, exchangeable cations (K⁺, Mg⁺⁺, and Ca⁺⁺), and total nitrogen in soil postharvest, indicating an improvement in soil chemical properties. Total carbon content increased in soil with green manure incorporated, but decreased in the chemical fertilized soil, suggesting that sorghum cultivation using green manure may sequester carbon in soils. The yield of sorghum cultivated with green manure was not different from the yield of sorghum cultivated with chemical fertilizers. These results suggest that the mixture of hairy vetch and manure barley can be a useful chemical fertilizer alternative in sorghum cultivation.