Local Variability of Soil Nutrient Parameters in Japanese Small Size Field

Abstract

Local variability of soil parameters, NO3-N, EC and pH, was evaluated in square areas of 4.2×4.2m² for maize growing field (0.6m grid) and of 10×10m² for paddy field (1m grid, dry soil after harvesting). Soil samples were collected from three layers: top (5-15cm deep), middle (15-25cm deep) and bottom (25-35cm deep). Spatial data of NO3-N followed a logarithmic normal distribution in the maize field and a normal distribution in the paddy field. In the maize field, high correlation between the layers was estimated in terms of NO3-N. Semi-variance analysis indicated uniform spatial variance in the maize field, and in the paddy field uniform variance along the crop rows but logarithmic variance along the lateral.