Physico-Chemical Characteristics of Soils under Cacao Production System in Davao de Oro, Philippines

Abstract

The study was conducted to understand the physico-chemical characteristics of the soils under cacao production system in Davao de Oro, Philippines. Eight (8) cacao farms were selected for detailed field characterization and sampling of soils for various nutrient analyses. Fertility status of each selected farm was determined by comparing the fertility properties of each soil with the critical nutrient level requirement for cacao. Results showed that most of the soils have a dark brown soil color in the upper horizons, and dark, yellowishbrown in the lower horizons. They range from moderately deep to very deep soil profile (19 to 150 cm), with very friable to extremely firm when moist, slightly sticky to very sticky, and slightly plastic to very plastic when soil consistence is wet. Lower elevations had shallow solum with high water table, resulting in the development of mottles and redoximorphic properties. The amount of clay ranged from 9 to 37%, with 18 to 40% for silt, and 30 to 68% for sand. Most of the cacao farms were intercropped with coconut, durian, lanzones, rubber, and banana. Most of the soils are moderate to slightly acidic, with pH values < 6.5 and CEC ranging from 10 to 34 meq/100g. Moreover, most of the areas have low organic matter (1.66%) except for the areas which continually applied organic matter during fertilization (4.60%). The amount of nitrogen (N) is optimum; however, phosphorus (P) was generally deficient in the soils of most cacao farms surveyed, while amount of potassium (K) ranges from 41.30 to 375.60 mg/kg.