Land Use Effects on Soil Physical Properties and Organic Carbon in Costa Rican Inceptisols.

This study analyzed the physical and hydrological properties of six land uses in Inceptisols of the Atlantic Region of Costa Rica: 2 perennial crops (Costa Rican guava and cacao in agroforestry); a native pasture; a 60 yr. old secondary forest; and, 2 cash crops under continuous rotation (pineapple and yam). Samples were collected to measure bulk density, penetration resistance, shear strength, water stable aggregates (WSA), mean weight diameter (MWD), carbon concentration in aggregates, total carbon content and C:N ratio at depth intervals of 10 cm up to 50 cm in depth. Water infiltration was measured in situ with double ring infiltrometers. The perennial land uses and native pasture reported significant differences in most of the physical properties evaluated in comparison with the cash crops and secondary forest at almost all depth intervals. The WSA and MWD were higher for the perennials and pasture, but in general, all land uses had WSA above 75%. The effect of aggregate size (< 0.25mm and > 0.25 mm) was not significant for the carbon concentration and C:N ratio. Results also indicated a significant correlation between aggregate carbon concentration and WSA and MWD for all land uses.