Effects of stock type on soil physical properties and losses of phosphorus and suspended sediment in surface runoff

摘要

By altering soil physical properties and dung deposition, livestock grazing can enhance the loss of phosphorus (P) and suspended sediment (SS) in surface runoff which can impair the quality of receiving water bodies. The impact of cattle, deer, and sheep on surface (0-5 cm) soil physical properties and P and SS losses in surface runoff was investigated. No significant difference was found between stock type and P and SS losses. However, significant differences were evident for the interaction of stock type with soil physical properties (bulk density, macroporosity, and saturated hydraulic conductivity-K_(sat). Furthermore, a gamma log generalised linear model detected a significant relationship between macroporosity, K_(sat) or time (days) since grazing and certain concentrations and loads of P fractions and SS losses, whereby more pore space, a greater infiltration rate or time since the paddock was last grazed decreased losses. This suggests that soil physical measurements may have the potentialto aid management to decrease P and SS losses in surface runoff.