Effects of Corn Residues on Soybean Yield

Field experiments were conducted to determine the corn (Zea mays L. cv. Tainung No.1) residues on the yield of the subsequent soybean 〔Glycine max (L.) Merr.〕 crops in 1992-1994. The results suggest that there is a beneficial effect in direct incorporation of corn residues into soil on soybean yield. Pod and grain yields of both Summer and Spring crops were significantly different in varieties and treatments in the study. For Nungyu 7, it showed that pod and grain yields of double amounts of corn residue were in average the highest among treatments in both crops. Pod and grain yields of 1993 were higher than that of 1992 in the summer growing season, but only grain yield of 1994 was superior than that of 1993 in the spring growing season. Grain yield increased by ca. 27 and 41% in average for the Summer and the Spring, respectively. Similar results were found for Kaohsiung sel. 10. It was 19 and 9% increase of grain yield for the Summer and the Spring, respectively. From the combined analysis of variance, 100-grain weight was the only yield component significant in residue treatments of two varieties in all years. Results of the correlation analysis showed that pod yield was the only factor positively correlated with grain yield in both varieties in both crops. This demonstrates that as pod yield increased, grain yield showed a corresponding increase.