Briefly describe three methods to reduce soil erosion on agricultural lands. Leaving strips of cover vegetation along contours to again slow run-off and reduce water erosion. Don't cultivate steep slopes, keep them for pasture lands instead. Don't overgraze pastures. Crop rotation can reduce soil erosion, IF one of the crops in the rotation is a cover crop like alfalfa, which reduces exposure of the soil to wind and rain.
Drip irrigation reduces soil transport due to splashing.
Tropical rainforest soils tend to be low in nutrients. During the cropping phase nutrients are made available to crops by cutting down a section of rainforest and either burning the vegetation or letting it decompose in place to release nutrients to the growing crops. Soil fertility levels in the cropped areas quickly drop due to harvests and leaching, and the plots must be abandoned after one or a few years. During the fallow period, plant secondary succession builds up vegetation biomass and a new store of nutrients in the previously cropped area. After about 20 years the area can again be cropped.