Yield potential of site-specific integrated pest and soil nutrient management at different harvest intervals under two commercial cocoa planting systems in Malaysia

Spatio-temporal variability of soil fertility and cocoa pod borer (CPB) infestation rate provides strategic information about the soil nutrients and CPB population densities at different harvest intervals. This enables the transitioning of cocoa fields (cooca-gliricidia and cocoa-coconut) from conventional to modern precision management. Geostatistical methods were applied to interpolate the data collected from a systematic grid based on a cluster of six cocoa tree stands for both fields and produce maps representing the spatial variability of all soil variables and CPB attack. Cocoa fresh bean weight and CPB infestation data were collected at two week-intervals from cocoa-gliricidia and cocoa-coconut. All field data points were geo-referenced by a differential global positioning system. Data were processed for possible outliers, and analysed by variography and interpolation techniques for quantification of spatial variability. Results showed that both plots exhibited definable spatial structures and were described by exponential models. Precision cocoa management recorded an increase in crop yield by 52.8 and 37.5% at cocoa-gliricidia and cocoa-coconut, respectively. Site-specific nutrient management and integrated pest control in the critical zones showed improvement in cocoa yields, especially during the peak harvest season.