Sampling single row subsurface drip tape in Trees

Take three cores from 0-15cm from under a tree starting from beside the drip tape and evenly spaced to within 5cm of the edge of the wetted zone. Ensure that the samples are kept inside the drip line of the canopy. Sample from 8-10 sites within the block, keeping to the main soil type for the block and avoiding excessively wet or dry areas.