Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 26, 1997
Publication Date: N/A
Technical Abstract: Conservation tillage (CnT) minimizes the mixing of plant debris into the topsoil and may promote a heterogeneous soil organic carbon (SOC) spatial pattern. Weed control efficacy may be influenced by the heterogeneous SOC pattern because of spatial variations in pesticide sorption and persistence. We tested the hypothesis that SOC contents in topsoil under CnT are more variable than conventional tillage (CvT). Topsoil (0-3 and 0-15 cm deep) was collected using a grid system (20- x 56-m plot, n = 40 per plot) from replicate plots under long-term (19 yrs) CnT and CvT. Soils under CnT had higher mean SOC contents and larger variances at both depths than soils under CvT. Simple contour plots of topsoil SOC contents showed the extensive heterogeneous pattern in the CnT plots and a more homogeneous distribution in the CvT plots. A variance ratio test (P=0.05) confirmed that the variance of pooled SOC contents in CnT plots was greater than in CvT plots, indicating more SOC variability.