Identifying critical soil water thresholds to decrease cattle treading damage risk

Abstract

ABSTRACTTo minimise soil compaction, land managers should limit cow grazing periods when soil water content (SWC) is greater than a critical water content (CWC) at which point soils are prone to treading damage. A laboratory-based method, the ‘proctor test’, has been used to identify the CWC in two intact Pallic soils collected from North and South Otago, New Zealand. We have attempted to relate the CWC to a simple field-based metric—the soil plastic limit—which can be measured by farmers as a proxy for CWC. Plastic limit was a suitable proxy for CWC in the North Otago soil only. In the South Otago soil, the CWC occurred at a lower SWC than the plastic limit. Although CWC varied across the two soil types, in both instances, it was reached at an SWC less than field capacity, while this was not always the case for plastic limit.