Soil sampling should take paddock variability into consideration. For example, clays have greater capacity to resist pH change (buffering) than loams, which are better buffered than sands. Samples should be taken at the surface and in the subsurface to determine a soil pH profile. This will detect subsurface acidity, which may underlie topsoils with an optimal pH.
Samples need to be properly located (e.g. GPS) to allow monitoring. Sampling should be repeated every 3 – 4 years to detect changes and allow adjustment of management practices