| The lack of available information regarding properties and hydrologic characterization of volcanic ash derived soils on steeplands in tropical climates of Central America might limit the transfer of research results on runoff, erosion, and productivity. Our aim was to characterize the soil properties and their hydrological pathways. Our aim was also to classify the soils of cultivated steeplands (35% of landscape), under tropical climate (1,330 mm and 23.3°C) at the “El Pital” watershed, Nicaragua, C.A. Chemical, physical, morphological, and mineralogical properties of volcanic ash derived soils were determined from 18 pedons, which were classified using Soil Taxonomy. Runoff and soil loss were measured in microwatersheds and compared with USLE-plots and estimated value generated by USLE model. Most of the soils were classified as Durustands, Haplustands, and Argiustolls. They had dark brown surface horizons (7.5YR 3/3, moist), high infiltration rates (11–18 cm hr−1 ), were moderately acid to slightly alkaline (pH(water) 5.5–7.4), had base saturations between 40% and 95%, and exhibited CEC values from 3.6 to 65.6-cmol kg−1. Halloysite and smectite were the main crystalline clay mineral components, but amorphous material of short-range order was predominant. Glassy amorphous materials were identified in thin section and grain mounts. The soil losses were 40-, 10-, and 4-Mg ha−1 yr−1 for the model, small plot, and field scale plot, respectively. Soil losses in microwatershed were observed only when restrictive clay and silica pans were close to the soil surface (<50 cm) and there were high intensity storm events (>25 mm h−1 ). Soil and water conservation strategies should consider the nature subsurface restrictive layers in volcanic ash derived soils to determine their susceptibility to soil and water erosion. However, the soil losses in general for these soils were below the tolerance level (10 Mg ha−1 y−1). Tillage erosion rate increased with increase in the slope gradient and was 57 Mg ha−1 y−1 under oxen-pulled plow on contour with 50% slope. |
