Microeconomic analyses of land management: The control of soil erosion under consumption risk and an empirical analysis of non-paddy terracing in the Philippines.

摘要

This dissertation addresses two questions related to private management of natural resources, control of non-point source pollution, and technical change. First, how does consumption risk affect a farm household's control of soil erosion in diverse agroecological conditions? Second, under what circumstances does a Filipino farmer control soil erosion and water runoff with non-paddy terraces? The answer to the first question is based on a dynamic-stochastic model of a farm household's consumption, saving, and allocation of labor to soil-loss prevention and off-farm work. The answer to the second question is based on a logit model estimated with data about individual terracing behavior, on-farm characteristics, market factors, environmental conditions, and extension programs in hilly, rainfed areas of the Philippines.;Both the theoretical and empirical results challenge existing theory and conventional wisdom about the effects of risk, poverty, population pressure, and land tenure on investments that conserve soil and water. The key theoretical result in Part I is that consumption risk encourages rather than discourages risk-averse farmers to invest in soil-conserving techniques and structures under certain environmental conditions.;Some of the empirical results in Part II are also contrarian. Existing dynamic optimization models of soil management do not generate predictions that cultivators who have smaller farms are more likely to terrace. Some factors that contribute to poverty and some microeconomic consequences of population pressure actually encourage terracing and, by implication, soil conservation. The fractions of a farm that are not owned by its cultivator do not affect her decision to terrace. Traditional extension methods are not as effective as active extension methods.;Although contrary in some instances to popular theory and conventional wisdom, these results are consistent with a view of non-paddy terraces as capital assets and with microeconomic arguments about the costs and benefits of producing such assets. These results provide a basis for governments of the Philippines and other countries, international development agencies, and non-governmental organizations to evaluate policies and programs that indirectly affect or directly promote control of agricultural runoff and sustainable land use.