Abstract
The erosion plot method for direct evaluation in agriculture became necessary to (1) quantify soil erosion on cocoa, areca and oil palm, (2) determine the most effective soil conservation, and (3) calculate nutrient content in sediment. The experiment was treated with three conservation practices and the conventional treatment as control in a completely randomised block design. The results showed for the areca land use, that soil conservation with ridges + maize produced the lowest erosion (1.68 t/ha). For cocoa land use, the ridges + groundnut treatment produced the lowest erosion (8.2 t/ha). For oil palm land use, the cover crop of Mucuna bracteata had lowest erosion yield (12.2 t/ha). Soil conservation techniques significantly affected the levels of organic C and available P under the cocoa land use, where ridges + maize have the lowest content of organic C and available P in soil sediment (1.03% and 0.69 ppm). Soil conservation at areca land use also has a significant effect on the levels of organic C and available N, but it did not affect significantly the levels of available P and exchangeable K sediments, where ridges + groundnut have lowest organic C and available N in sediment (1.4% and 0.18%). Furthermore, soil conservation on the land use of oil palm showed a significant effect on the levels of available P, but did not significantly affect the levels of organic C, available N and exchangeable K sediments. Soil conservation with cover crops Mucuna bracteata showed the lowest available P in sediments (0.86 ppm).