Fertility Gradients in Naturally Formed Terraces on Honduran Hillside Farms
1999
Walle, Robert J. | Sims, B. G.
Deposition of eroded sediment within soil conservation barriers may create a gradient of soil properties. Our objective was to determine the presence of soil fertility gradients in the naturally formed terraces of two representative conservation practices; contour grass barriers and stone walls. Soil samples were taken at five slope positions to depth of 20 cm, divided into 5-cm sections, with three replicates (60 samples per location). Samples were analyzed for texture, total Kjeldahl N, organic matter, and extractable P, K, Ca, and Mg. For both sites, the upper slope positions were lower in soil organic matter, nutrients, and silt than the lower positions. Within stone barriers, the silt fraction and extractable P contents showed gradients, with three of five positions different. Within grass barriers, a gradient was present for clay, with three of five positions different. Organic matter and Ca showed distinct gradients, with all positions different, increasing downslope. A position × depth interaction for organic matter was detected, showing surface removal and deposition along the lower slope positions. Identification of fertility gradients may lead to improved cropping systems and fertilizer management and to refinement of agronomic research on hillside farms.
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