Spatial analysis of oil palm growth and soil properties in a plantation in Nigeria

Relationships between spatially correlated soil properties and crop performance at field scale are vital when planning specific site management for sustainable crop production. This study investigated the correlations and relationships between some soil properties and oil palm trunk diameter at breast height (DBH) at the Oil Palm Plantation, Teaching and Research Farm, Ekiti State University, Ado Ekiti, southwest Nigeria. Soil samples were collected from 0 to 10 cm surface layer at 81 georeferenced points within the plantation to determine soil properties and oil palm trunk DBH. The soil properties and trunk DBH varied widely with particle density, soil pH, bulk density, and field capacity showing least variability (coefficient of variation (CV) < 12%), oil palm trunk DBH, soil organic matter, air capacity, soil texture, soil water content, permanent wilting point, total porosity, and available water showed moderate variability (12.0% < CV < 60.0%), while saturated hydraulic conductivity was highly variable (CV > 60%). Classical linear multiple regression showed that the sand, soil pH, and bulk density could only explain 16% of the variability in DBH, whereas the principal component regression analysis had explained about 72% of the variability in DBH. The minimum suitable sampling interval for spatially independent variables was 10 m (1 lag), while it was the sampling point (0 lag) for spatially dependent variables. The results could be used as baseline data for delineating soil and nutrient management zones for the oil palm plantation and other crops in the study area.