A scenario modelling approach to assess management impacts on soil erosion in coffee systems in Central America

Abstract

Soil erosion is one of the major causes of soil degradation worldwide, because it causes the depletion of soil organic carbon, nutrients, and water holding capacity. In Central America, coffee production is vulnerable to soil erosion since it often occupies steep slopes with high annual precipitation. To assess management options to control erosion, soil and vegetation field data were collected from 90 Costa Rican and 96 Guatemalan coffee plantations, mainly shaded, distributed in six coffee production areas. Soil erosion was modelled using the RUSLE (Revised Universal Soil Loss Equation), integrating soil and vegetation cover field data, with remote sensing data. Management scenarios were developed to assess the role of two principal coffee management strategies in mitigating soil erosion: increasing vegetation cover, and soil conservation practices. Average estimated erosion rates of 17 and 7 Mg ha−1 yr−1 were predicted for plantations of Costa Rica and Guatemala, respectively, with erosion from coffee plantations representing between 23% and 40% of the estimated erosion of the watershed within which they were situated. If all plantations achieved vegetation cover equivalent to the best 25% of plantations, the estimated erosion would be reduced by 7% in Costa Rica and 8% in Guatemala. If all plantations implemented soil conservation practices, estimated erosion would be reduced by 11% in Costa Rica and 35% in Guatemala. With the two combined management strategies a reduction of estimated erosion of 17% and 40% was predicted in Costa Rica and Guatemala, respectively. The reduction in erosion from soil conservation or better vegetative cover varied among regions within countries depending on current management, local climate, and topography. These results show the importance of coffee system and soil management practices in moderating erosion from highland coffee production, and how RUSLE analyses can identify priority practices in different regions supporting more effective policies to reduce soil erosion.