Changes in the properties of a volcanic soil (andisol) in Leyte (Philippines) due to conversion of forest to other land uses
1999
Asio, V.B. | John, R. | Stahr, K. (Visayas State Coll. of Agriculture, Baybay, Leyte 6521-A (Philippines). Dept. of Agronomy and Soil Science)
The soils under adjacent areas of forest, grassland, pasture and bushland were examined and compared to determine changes in their properties as a result of the conversion of the forest to the secondary land uses. The study site, located in Leyte [Philippines], is characterized by warm humid tropical climate, rainforest natural vegetation and volcanic soil (Andisol). Results revealed that forest conversion generally resulted in a decrease in organic C, total N, porosity, aggregate stability, available water, and quality of soil consistence and structure as well as increased soil erosion. On the other hand, the conversion appeared to have increased soil erosion. On the other hand, the conversion appeared to have increased available N. K, Ca and Mg of the soil. The increase in N was due to enhanced mineralization while that of K, Ca and Mg was due to the ash from periodic burning, rejuvination effect of soil erosion and enhanced rock weathering. The negative and positive soil changes were related to the degree of human disturbances. Contrary to common knowledge, the results showed that forest conversion to secondary land uses particularly agriculture, may lead to an improvement in some soil chemical properties. Most of the major negative soil changes are believed to have occurred in the past probably as the immediate effect of forest removal and soil cultivation, and not necessarily due to the present secondary land uses
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