A soil sampling protocol to minimise the spatial variability in soil test values in New Zealand hill country

摘要

Because of the large inherent changes over time and space, non#x2010;systematic sampling in hill country can result in high coefficients of variation (CV 18#x2013;55) in soil phosphorus (P), sulphur (S), and potassium (K) levels between measurements. The components of spatial variability were measured on 20 hill#x2010;country sheep and beef farms. For Olsen P, 38 of the total farm variance was measured within 1 m of a fixed point, 27 within 100 m, and 35 between paddocks within a farm block. With soil pH, quick test K, and sulphate S, there was greater variation within 1 m, less within 100 m, and very little between paddocks, compared with Olsen P. From this information, a sampling protocol was designed to achieve the target CV for Olsen P (15#x2013;20).