Intensive Vegetable Production Degrades Volcanic Ash Soil in Cabintan, Ormoc City, Philippines

Long-term intensive cultivation leads to soil-related problems. This study was conducted to know the changes in physico-chemical properties of volcanic ash soil (Andisol) in Barangay Cabintan, Ormoc City, Leyte after ten years of intensive vegetable production. Five sampling sites were selected, representing fallow and intensively cultivated areas. The soils were collected and analyzed for particle size analysis (PSA), bulk density (Db), soil pH, organic matter (OM), nitrogen (N), available phosphorus (P) and exchangeable bases potassium (K), magnesium (Mg), calcium (Ca), and sodium (Na). The findings of the current study were compared to the results reported by the ACIAR project ten years ago. The results revealed that the soil physico-chemical properties of Andisol changed within ten years. There were significant differences in soil physicochemical properties of Andisol across sites and depths as influenced by the two types of soil management over ten years. Soil management practices influenced the nutrient supplying capacity and the physico-chemical properties of the soil. Soil texture did not vary except for sites C and E (intensively cultivated areas). The bulk density remained low while the soil pH, soil organic matter, nitrogen, and exchangeable bases decreased. However, the available phosphorus increased under intensive vegetable production. The overall results highlighted the need to employ the appropriate soil management, specifically fertilizer application. An accurate and exact combination of organic and inorganic fertilizers is highly recommended in the area to obtain the desired vegetable yield.