Characteristics, fertility status, and management of degraded upland soils in Leyte, Philippines.
2007
Asio, V.B., Leyte State Univ., Baybay, Leyte (Philippines) Dept. of Agronomy and Soil Science
Soil degradation is one of the most serious ecological problems in the Philippines today. In Leyte, large upland areas have been degraded primarily due to erosion and organic matter and nutrient losses as a result of conversion of forests into agriculture land uses. Degraded upland soils in Leyte can be grouped into three based on the land forms where they occur: the fragile young soils from recent volcanic materials (mostly Andisols and some Inceptisols) on higher elevations and rugged topography. The higher weathered but more resilient soils (Ultisols) on the more stable slopes on the lower elevations, and the poorly to moderately developed soils (mostly calcareous) on sedimentary hills along coastal plains (inceptisols and Mollisols). Degraded upland soils in the island have several chemical and physical infertility problems that limit their use for crop production the most common among which are strongly acidic pH, low organic matter content, low phosphorous availability, and plastic, sticky and hard characteristics. Organic matter management, reforestation, hedgerow intercropping, and 'rainforestation farming' are suggested approaches/technologies for the sustainable management of degraded upland soils. The planting of the diesel oil plant Jathropa curcas in degraded uplands could be successful if accompanied by appropriate soil management strategies but its long-term ecological impact is not yet clear and needs to be studied.
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