Fig. 4. Comparison of actual NEPAC pH (a) and lime requirement (LR: b) values with values estimated by cross validation of block kriging based on either the most dense point sampling strategy (•, 10 points ha^–1 [CP_0.1ha]) or a sparser strategy of 2.5 points ha^–1 (P_{0.4 ha}). Estimated CP_0.1ha values are from cross validation while estimated P_{0.4 ha} values represent the combination of results from cross and jackknife validation.