Cassava soils and nutrient management in South Vietnam

In South Vietnam, cassava is grown both in the highlands and in the delta, on different soil groups, such as the yellowish red soils, grey degraded soils, alluvial soils and acid sulfate soils. These soils are located mostly in the Central Highlands, the Coastal Region and the Eastern Region of South Vietnam, where perrenial crops such as coffee, tea and rubber are also grown. Cassava is often grown on unfertile soils. As a result, the soil becomes poorer and poorer leading to a decline in soil productivity. Sloping lands under cassava cultivation are quickly eroded after deforestation. Besides, the soil organic matter content also decreases due to forest burning and leveling and as a result of the direct impact of sunshine and rain drops. The soil will be chemically and physically degraded. Similarly, the soil microbial activity also declines. To obtain a high and sustainable yield of cassava, it is necessary to use some investment for cassava cultivation. But most cassava farmers are too poor to invest in fertilizers, so the soils quickly lose their productivity. Therefore, better nutrient management is required to maintain sustainable cropping systems, by reducing erosion and preventing a decline in soil fertility.