Within-site drivers for soil nutrient variability in plantation forests: A case study from dry sub-humid New Zealand

Precise spatial information on soil properties in plantation forests is needed to improve nutrient management and sustain productivity. Soil nitrogen, phosphorus, potassium, organic matter, carbon boron are important determinants indicators of fertility quality. Particularly forests, these highly variable space time. In this study, soils were sampled from three forest sites a dry sub-humid region near Blenheim, New Zealand. Thirty sampling points selected, samples collected the across range slope aspect strata. analysed for total (totC), nitrogen (totN), phosphorus (totP), extractable potassium (exK) hot-water (exB). All examined varied significantly (p < 0.05) within sites. A set fine-scale (5 m resolution) topographic surfaces, that might explain variability, then interpolated or derived geographic system software. Topographic surfaces included elevation, aspect, slope, profile plan curvature, position index (TPI), wetness (TWI), wind exposition (WEI), morphometric protection (MPI). generalised linear mixed-effect model was applied develop predictive models. The study found all positively correlated with MPI negatively WEI. This indicated shelter surrounding relief wind. Interestingly, within-site levels both curvature (PrCurv) index, indicating movement through surface moisture. modelling approach has potential application sustainable using spatially-precise estimates fertility.