PREDICTION OF MACADAMIA NUT SPOILAGE FOR HARVEST DECISION-MAKING

Macadamia nuts are harvested from the orchard floor either manually or by using mechanical sweepers. Nuts on the orchard floor gradually tur n mouldy and rancid after a period of exposure to the orchard environm ent. Annual lass of this nature is significant and varies spatially as well as temporally. Increasing harvesting frequency decreases this lo ss but increases the cost of harvesting. It is desirable to balance th ese costs optimally. A way of predicting this loss is essential to rea ch an optimal trade-off between nut loss and harvesting cost. This pap er discusses a model for predicting this loss as a function of the soi l moisture content of the orchard floor and the time for which the nut s lie on the orchard floor. The model was interfaced to a geographical information system for showing the environmental or the orchard site impact on nut spoilage. This impact information is useful in the selec tion of harvesting equipment of appropriate size, harvest scheduling a nd the selection of suitable orchard sites for nut production. (C) 199 6 Silsoe Research Institute