Soil Types and Geographical Forms of the Degraded Uplands of Bohol, Philippines

Abstract

The main objective of this study was to identify the soil types and geographical forms in the degraded uplands of Bohol. This was accomplished by gathering secondary data from concerned institutions and from previous research results. Bohol is geographically located between 123°40’ and 124°40’ East longitude and extends from 9°30’ to 10°15’ North latitude, in the central portion of Visayas. It is generally flat and plain with only few mountainous areas at the northeastern portion suitable for massive cultivation of agricultural products. Some of these mountainous areas, particularly those preserved from degradation, can serve as habitat for interesting flora and fauna as well as natural land forms that travelers look for, such as the landform for which Bohol has been noted, the Chocolate Hills. The existing general land use data of Bohol has 13 categories. The top three categories in terms of area are the agricultural land, timberland and infra utilities. Agricultural land constitutes about 66.54% of the province total land area while timberland is only 24.6%. Approximately 167,160 hectares or 40.6% of the total provincial land area have slope gradients of 0-8%, largely covering the central of northern areas which comprise the prime agricultural zone utilized or irrigated and rainfed palay and corn production. The areas with 8-18% slopes accounted for 29% which is mostly planted with coconut, corn and subsistence crops and open/idle and eroded land areas. The rolling to mountain areas with slopes of 18% and above cover about 123,930 hectares or 30% of Bohol land area. Areas with slopes of 18% and above have been disturbed and exploited particularly for subsistence farming. Soil types of the degraded uplands of Bohol are of different soil classification. The most extensive soil type is Ubay clay which occurs from the central (Carmen and Sierra Bullones) to the north and northeastern (San Miguel to Alicia) and northwestern areas of Bohol. Faraon clay predominates at the southern municipalities of Lila, Dimiao, Valencia and Garcia Hernandez.