Modeling Economic and Environmental Impacts of Landuse change in the Fort Cobb Basin

Abstract

Watershed management plans need to reflect the economic interests of landowners. Row cropssuch as peanuts grown on Fort Cobb watershed generate more income to the farmers, however theconcerns are excessive sediment and nutrient loading to the streams. Conservation Reserve Program(CRP) and bioenergy crops were investigated as alternatives. Two approaches were used: Incomemaximization approach subject to sediment and nutrient loading constraints and sediment and nutrientloading minimization approach subject to budget constraint for water quality incentives. Soil and WaterAssessment Tool (SWAT) was used to determine sediment and nutrient loading. General AlgebraicModeling System (GAMS) was used to make land use decisions. The outputs from SWAT and economicdata were used to construct a programming model. Switchgrass, conventional and minimum tillage wheat,peanuts, grain sorghum, and Conservation Reserve Program lands were used. Replacement of peanuts byswitchgrass or CRP lands reduces sediment loading by 99%. The loss in income for the same amount ofloading reduction, as a result of replacement of peanuts by switchgrass is less than it is for replacement byCRP or other crops. The incentive required per ton of sediment or nutrient reduced as a result ofreplacement of croplands by CRP and minimum tillage wheat is about one and half times higher than thepayment required for replacement by switchgrass. With payments lower than required for CRP, it ispossible to have produce grow switchgrass for energy purpose and at the same time get more waterquality benefits. The optimal land distribution from the society perspective is different from the privateperspective especially if the damage costs are high. From the society perspective, if damage costs areconsidered, it could be more profitable to grow a crop that generates less income to the producerscompared to one that generates a higher income but with more damage to the environment.