Effect of N Fertilizer and Corn Residue Management on Organic Matter in Minnesota Mollisols
1982
Bloom, P. R. | Schuh, W. M. | Malzer, G. L. | Nelson, W. W. | Evans, S. D.
Two long-term continuous corn (Zea mays L.) experiments were used to determine the effect of the rate of stover return on soil organic matter in high organic matter mollisols (O.C. > 2.4%). One experiment was an N rate experiment which had been cropped for 19 years. The other was a stover-fertility management study which had been cropped for 13 years in which there were two stover management treatments: total removal and plowdown, both at high and low fertility. In the N rate experiment a 3-ton ha⁻¹ yr⁻¹ difference in stover yield between the low and high N rates resulted in a 4.5% less organic carbon content for the lower N rate after 19 years. All of the treatments in the stover management study had no significant changes in organic matter content after 13 years except for the low fertility-stover removal treatment which had 15% less organic carbon. It was concluded that for precise estimates of treatment effects on organic carbon loss in mollisols, longer treatment times are needed.
显示更多 [+] 显示较少 [-]