AbstractVarious cropping systems for yam production were tested in the runoff plots at the Olive River Watershed where soil losses were measured. Yellow yam yields ranged between 42 and 63 t/ha, but differences were not significant for either of the two experimental years. Marketable yields were 47% to 57% of the gross yields. When yam was intercropped with Irish potato, gross yields of potato ranged from 12 to 14 t/ha. Marketable yields were 80 to 85% of the gross yields. The lower yam yields in treatments with more than one intercrop were offset by the extra cash flow produced by the intercrops. When the 2-year data were pooled, significant yield differences between treatments were obtained, indicating that intercrops affect yam yields adversely. The Napier grass buffer strip produced 42 to 48 t/ha/yr (green weight). Alternative soil conservation measures, other than bench terracing, such as hillside ditches and grass buffer strips, and intercropping with yam, increased production and crop diversification in hillsides; are relatively cheaper, simpler, easier to construct, and very effective in terms of soil conservation in the hillsides.
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