Author : Orlina, Eva R.

Summary : Three treatments such as traditional farmers' practice (T1), strip-tilled-mulched with natural vegetative strips (T2), and strip-tilled-mulched with Gliricidia sepium hedgerows (T3) were tested in order to evaluate their effects on selected physical and chemical soil properties, soil erosion, and productivity of corn and mungbean in a clayey soil with 45-60% slope. Results showed that treatments did not significantly alter some soil physical properties such as bulk density, porosity, and moisture content after two cropping seasons. Aggregation changed among treatments as cultivation in T1 enhanced pulverizing effect on all aggregate sizes. T2 effectively maintained aggregation of 0.5 to 2mm aggregates while T3 increased aggregate stability of >2mm aggregates. Soil chemical properties like pH, OM, N, P, and K increased in all treatments but only K in T3 showed significant difference. Within treatment, there were significant increases of K in T1 and T2, and P in T2 and T3 after two croppings. A total of 213.66 Mg ha-1 was eroded in T1, but this was reduced to almost 50% in T2 and 25% in T3. Compared with that in T1, soil loss reduction in T3 minimized N and K losses by 80% and 78% respectively. T2 reduced N and K losses by 32% and 42% respectively. Phosphorus losses after two croppings were similar among the three treatments.