Kirsten Barlow1, Sebastian Ie2, Ben Fleay2
2 Precision Agriculture, PO Box 691, Ballarat, Vic 3353, www.precisionagriculture.com.au,
Soil constraints such as acidity, sodicity and nutrient availability can cause significant losses in production, limit crop choice, and further reduce the health of our soil resources if untreated. Grid soil sampling is a proven strategy to identify and enable targeted amelioration of soil constraints across a paddock. This paper presents the results of grid soil mapping on 289 commercial paddocks, investigating the relationships between soil pH, CEC, ESP and soil test P observed in the grid mapped surface soil data. The results highlight the variability within individual paddocks for these soil characteristics. Whilst some soil characteristics (e.g., pH and CEC) were well correlated in some paddocks, for most other characteristics up to 75% of paddocks had no consistent trends between the soil test data with correlation coefficients of between -0.5 to 0.5. Grid soil sampling allows the different patterns of spatial variation to be determined for individual soil properties, and enables separate variable rate strategies to be developed.