Sustainability of commercial vegetable production under fallow systems in the uplands of Mindanao, the Philippines

The quality of fallow lands in northern Mindanao, the Philippines, was asse ssed with a farm survey and soil sampling in order to understand land-use d ynamics under upland commercial vegetable production systems. Twenty-one pe rcent of commercial vegetable growers practiced fallow systems, with an ave rage re-cultivation period of four years. The soils of the fallow lands wer e highly acidic, nutrient poor, and higher in exchangeable aluminum compare d to lands currently under cultivation. Land fallowing was more prominent o n large farms and those with higher farm labor requirements. Two distinct g roups of land fallowers were identified. The first represented fallowers wi th a positive net return from vegetable crops while the second, and larger, group represented land fallowers with negative net return from vegetable c rops. Re-cultivation of fallow lands was more common in the second group. T o rejuvenate fallow lands, timber tree planting was the most preferred opti on of the first group while fruit trees were preferred by the second group. In light of the apparently slow rate of soil fertility regeneration, the l ack of capital among most land fallowers, and the increasing demand for ara ble land to raise farm income, planting of trees on cultivated lands before their being set aside as fallow for natural fertility regeneration is sugg ested as a potential measure to increase farm income and the sustainability of upland commercial vegetable production under fallow systems.