In addition to a weakening demand for their products, livestock producers have faced historically high feed costs and struggle to meet increasingly stringent regulations on the management of animal wastes. In two related papers, we analyze the important linkages between farm management adjustments and changes in farm income and restrictions on land application of nutrients. Using regional and representative farm mathematical programming models, we account explicitly for new restrictions on land application of nutrients, and determine the optimal farm management responses to the regulations. Our models are specifically applied to confined animal feeding operations (CAFOs) in New York State. We incorporate into our model empirical methods for estimating environmental nutrient loading and thus determine the effects of the regulations on the distributions of nitrogen and phosphorus residuals. The combination of our mathematical methods and the availability of two unique datasets allows for the assessment of the differential effects on income and nutrient loading for specific New York State production regions. Our results suggest that without any regulation, on-farm manure application would lead to soil nutrient levels well in excess of crop requirements. While the regulations will correct for this problem at the farm and regional levels, our results indicate that CAFOs could experience considerable income losses that depend critically on the cost of off-site manure disposal. Our results also indicate that cropland in the region could take on enhanced value for waste disposal and that significant risks of nutrient loading remain during extreme weather events. In a third essay, we present a stylized optimization model for Nigeria's energy sector that incorporates important social-economic objectives with traditional energysector planning goals of resource allocation and cost minimization. With a rapidly growing economy, Nigeria aspires to use revenue from rent of its natural resources to fund economic development. To this end, the formulation of energy-sector planning techniques has been an important objective for scholars and policy makers. We offer a new approach with our development of a resource-planning tool useful for a peculiar economic environment that integrates elements from the macroeconomics, open economy and natural resource literatures.