Influence of pastoral fallow on plant root growth and soil physical and chemical characteristics in a hill pasture.

摘要

In field trials at Ballantrae, New Zealand, a comparison was made of the effects of pastoral fallow and rotational grazing by sheep on root growth and soil physical and chemical properties. There was significantly less root biomass at 0-50 mm soil depth in the fallowed sward than the grazed sward. Compared with the grazed treatment, pastoral fallow increased soil air permeability at 500 mm tension by 38%, saturated hydraulic conductivity by 26%, unsaturated hydraulic conductivity at 20 mm tension by 67% and soil moisture by 10-15%, and reduced soil bulk density by 11%. Fallowing had little effect on soil nutrients either at the end of fallowing, except for small reductions in K and mineral N levels at 0-75 mm soil depth, or two to three years after fallowing.