STUDY OF MINERAL NUTRIENT LOSSES FROM OIL PALM EMPTY FRUIT BUNCHES DURING TEMPORARY STORAGE

摘要

Depending on the operational organization adopted by a plantation, empty fruit bunches (EFB) fresh from the mill are sometimes stored for a few days, either at the mill exit or on plot edges, before being spread in the field. Exposed to rainfall this way, the heaps are subject to substantial leaching of mineral nutrients. The trial conducted studied the dynamics of mineral nutrient release from a heap of fresh EFB stored in an open area and exposed to the elements. Watering was carried out to top up the rainfall and reach the rainfall levels defined by the protocol. Different storage times were studied over a period of two weeks. Mineral nutrient release was rapid, especially for potassium, magnesium and boron. The release rates varied substantially depending on the nutrient and EFB position in the heap, with a wide range between the top and bottom of the heap, associated with the degree of mineralization. The released mineral nutrients accumulated in the EFB at the bottom of the heap. The most surprising result was the speed with which potassium, the main nutrient contained in EFB, was released: a fortnight into the trial, 73% of the potassium initially contained in the EFB in the upper part of the heap had been released (48% for magnesium and 60% for boron), as opposed to 16% for the EFB at the bottom of the heap. A rapid estimation of financial losses cumulated over a year's production of EFB indicated the foregone earnings for the plantation and revealed the merits of returning EFB to the field immediately on leaving the mill. Any delay in application leads to a significant drop in the agricultural value of fresh EFB.