Monday, 10 February 2020
The proof is in the pudding: WFST
The alternative practice of Whole Farm Soil Testing (WFST) is a responsible approach to nutrient management. ARL’s analysis of accumulated laboratory data has shown that it improves nutrient management by reducing nutrient variation between paddocks.
Since 2011 Ravensdown has promoted the alternative soil sampling approach of WFST where paddocks are sampled individually, along GPS transects, to provide detailed information on soil nutrient status. Coupled with the ability to develop nutrient management plans, integrated with proof of placement technology, the aim is to help farmers reduce variability of nutrient levels between paddocks – improving nutrient efficiency and ultimately soil fertility.
By comparison, the conventional approach to soil sampling is to divide the farm into blocks that represent areas of different soil types, slope, land use and fertiliser history. A representative paddock from each block is then selected to be used as a monitor paddock from which soil samples are collected for analysis. Fertiliser applications for each block would then be based on soil test results obtained for the monitor paddocks that may cover less than 10 % of the farm.
Reducing high soil nutrient levels and increasing sub optimal levels over time has positive economic and environmental consequences. From ARL’s sample numbers of 160 farms over an 11-year period (2004-2017) the figures show an encouraging trend for all parameters from an environmental and economic perspective. Figures 1, 2 and 3 all show trends of shifting towards the optimum range as a result of Whole Farm Soil Testing.