Evaluation of contour barriers for soil and water conservation in Western Pare low land, Tanzania
Rwehumbiza, F.B.R;|Hatibu, N;|Kishebuka, S.R / 1999

A study was undertaken in Mwanga District in the Western Pare Low Lands (WPLL) for seven seasons (1993-19990 to investigate the performance of three soil and water conservation techniques with regard to the production of maize, on land with 8% slope. Conservation treatments were, stone binding (SB), contour ridging (CR), and live barriers (LB). Control treatments were flat cultivation (FC) and zero tillage (ZT). The treatment had no significant effect on profile moisture content. However, average over entire study period and during long rains. SB,CR, and LB performed equally well with grain yield of between 2.5 to 2.7 tons per hectare. Flat Cultivation had 2.2 tons hectare while ZT had only 1.7 tons ha. Between treatment and during short rains, grain yield varies with in a very narrow range of 0.8 to 0.9 tons ha. If the 1997/98 seasons which was abnormal (El Nino rains) is excluded, overall mean grain yield would be very low at 0.3 tons ha. Stone bunding and live barrier treatments has an additional advantage in that the barriers (5m apart) had over the year’s been transformed into bench terraces. Given the small increment in yield, which was realized, the techniques cannot be recommended for moisture conservation in this agro-ecological zone. However, since the barriers were effective in controlling soil crip down slope, they could be recommended as a long-term strategy for soil erosion control where this is considered a threat.