| Popis: |
The potential of an intact rye cover crop to reduce machine-induced compaction was the subject of this study. A randomized complete block field experiment was conducted in southwest Virginia in a fine, mixed, mesic, Aquic Agriudolls and in a fine-loamy, mixed, mesic, Typic Hapludults. Three cover-cropped treatments and one fall-tilled fallow treatment were analyzed. The treatments permitted investigation of the effects of a crop, the condition of the crop, and the contribution of root reinforcement to the alteration of soil response to machine traffic. Effects resulting from three levels of traffic—one, three, and five passes—were investigated. Undisturbed soil core samples were analyzed to determine the effects of machine traffic on dry bulk density, pore size distribution, and saturated hydraulic conductivity. Measurable soil response to machine traffic was limited to the uppermost 150 mm of the soil profile. Treatments that included a rye cover produced samples with significantly lower dry bulk densities and higher noncapillary porosities than the bare soil treatment for the soil surface layer (25-75 mm) following multiple machine passes. Soil compaction appeared to be reduced by the reinforcing effect of a network of undisturbed roots within the soil. There was no convincing evidence that above-ground biomass contributed directly to the reduction of machine-induced compaction effects. |
