Assessment of Soil Degradation in Sitio Marulay, Lunga, Valencia, Negros Oriental, Philippines

Abstract

This study determined the extent of soil degradation in Sitio Marulay, Valencia, Negros Oriental. Biophysical and socio-economic factors were assessed consisting of topography, climate, soil, vegetation, population, migration, livelihood, income and farming practices. Factors that have significant impact on the soil quality were identified to determine the extent and severity of soil degradation brought about by its present land-use using a set of criteria described as low, moderate, severe and highly severe.

Sitio Marulay is an upland area with a slope of 30-50% . From 2003 to 2007, the monthly average rainfall was 104 mm while the annual average rainfall was 1,216 mm. During the months of June to December, rainfall was higher ranging from 103-189 mm with subsequent water runoff. The clay-textured soil in Sitio Marulay can be considered as moderately erodible with acidic soil pH on steeper slope. This indicates that erosion is taking place. There was minimal vegetation on gently sloping land situated at higher elevation since the area has been cleared for farming. In contrast, clusters of mahogany trees were found along steep slopes that were established to mitigate soil erosion and landslides. However, some steep areas were severely eroded due to lack of vegetation.

A total of four (4) families residing in the area as well as other land speculators primarily used Sitio Marulay for agriculture. The farmers rarely practiced soil and water conservation methods except planting trees on steep slopes to prevent soil erosion. The population in Sitio Marulay is expected to increase after barangay officials in Lunga have sttled the issue on land claims. Consequently, farming activities will also intensify to meet the demands for food as settlement increases.

Considering all factors that contribute to soil degradation, such as amount of rainfall, type of soil, slope, vegetation, population, farming practices and land-use, the extent and severity of soil degradation in Sitio Marulay can be considered as moderate. As a guide to environmental resource managers of Sitio Marulay, vegetative and cultural methods of soil and water conservation such as contour hedgerows, multi-storey cropping, use of organic fertilizers, crop rotation and establishment of mini-storey on steep slopes are highly recommended. This is to improve soil quality and minimize soil degradation.