耕作对土壤生物碳动态变化的影响

EFFECTS OF TILLAGE ON DYNAMICS OF SOIL BIOMASS CARBON

本文讨论了耕作方法对行作玉米地土壤生物碳动态变化的影响。实验证明，传统耕法、短期免耕和长期免耕处理中的不同点位，土壤生物碳量分布有系统性的差异。土壤生物碳从播种后开始上升，至玉米吐丝期达最高峰，而后下降。其变化趋势与根系生长量相关。长期免耕土壤生物碳量的空间变量与土壤水分含量的空间变量有明显的相关性。

The objective of this study was to examine the effects of tillage on soil microbial biomass carbon under a crop of corn (Zea mays L.) Soil microbial biomass carbon was measured every two weeks and every month in conventional tillage (CT), l-year no-tillage(SNT), and long-term(> 15 years) no-tillage (LNT) plots using the chloroform fumigation-extraction technique.The plots are located near Guelph, Ontario, Canada on a Typic Hapludalf (loam)soil.Sampling sites were in the corn row, directly between corn rows(interrow), and half waybetween the row and interrow(quarter row). Systematic spatial differences in soil microbial biomass carbon within and between tillage treatments were observed throughout the entire growing season of crop. The major changes in the biomass occurred as a large increase between the time of planting and the time of silking and were correlated with predicted and expected root growth.Spatial variations of LNT biomass carbon were significantly correlated to spatial variations in soil water content over the crop growth season.