Optimal Management of Soil Quality Stocks and Long-Term Consequences of Land Degradation for Smallholder Farmers in Malawi

Abstract

While soil degradation has long-term consequences, static models which form the bulk of studies on this topic in Africa, do not account for the inter-temporal dimensions of optimal resource management. This paper used an inter-temporal optimisation framework, which considered soil in a time-dependent resource extraction perspective. We have demonstrated that soil degradation is causing an enormous reduction in productive value of smallholder land in Malawi. Current user cost of soil quality among smallholder farmers, which represents annual loss in productive value of land, was estimated to be US$21 per hectare. Based on this value and land area under smallholder agriculture in Malawi, economic costs of soil degradation among smallholder farmers were estimated to amount to 14% of the agricultural GDP for Malawi. Although smallholder farmers’ current practices are sub-optimal to Steady State solutions, they are above static solutions. This demonstrates that smallholder farmers have some private incentives to invest in the soil quality stock. Smallholder farmers internalise some of the dynamic costs of soil degradation under the current practices. However, a sensitivity analysis on a slightly higher discount rate indicates that SS solutions closely resemble the prevailing smallholder farming practices. This suggests that smallholder farmers may be overexploiting soil quality stock because they have a high time preference. That is, they value the current consumption more than their future consumption and wellbeing. High levels of poverty in Malawi and serious lack of viable alternatives to subsistence farming may be influencing such behaviour. Promoting more viable land use alternatives than subsistence farming and formuling policies that help transform smallholder agriculture into a profitable enterprise will not only increase the cost of degrading the soil, but also encourage farmers to invest in the soil quality stock.