Spatial variability of soil fertility variables influencing yield in oil palm (Elaeis guineensis Jacq.)

This study reports on the spatial variability of soil fertility variables influencing oil palm yield in small-scale plots situated at varying topographic positions. For each topographic position, Yield-influencing Variables (YIVs) were determined and subjected to spatial data analyses involving variography and interpolation (inverse distance weighting). Results showed that the spatial structure of YIVs differed across topographic positions. The optimum sampling strategy was found to depend on the type of variable being investigated and its topographic position. A management zone concept with topography as the delineation factor seemed appropriate for fertility management. Only potassium (K) showed a clear demarcation of zones with high, moderate or low values and hence the need for variable rate management.