Investigation of the potential of conservation tillage practices on soil erosion control on the slopes of the Uluguru mountain ranges
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Date
2015
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Publisher
Sokoine University of Agriculture.
Abstract
This study was conducted in Kolero village in the Uluguru Mountain ranges to investigate the potential of conservation tillage on soil erosion control on steep slopes. Randomized complete block design was employed, zero and strip tillage conservation methods were practised versus the conventional shallow tillage in controlling soil erosion. The effect of using cover crops namely; lablab and cowpea were also investigated. The main crop was maize. The study area has an average slope of 56% and the soil is sand clay loam for the top arable soil which has erodibility ranging from 0.012 to 0.019 t-ha-h/ha-MJ-mm. The area has annual rainfall of 1936.5 mm and rainfall erosivity of 8676.5 MJ mm/ha-h-yr. For every rainstorm, runoff and soil loss generated were measured. The multidivisor system was set to collect one eighth of the runoff into the drum. The crop management factor (C), was determined throughout the season. Conservation tillage treatments had small C values as compared to conventional tillage treatments hence reduction in soil losses. Soil loss for shallow tillage treatments without cover crops on contrast registered the least soil loss of 91.8t/ha as compared to zero and strip tillage which registered 159.3 and 118.3t/ha, respectively. Soil loss for strip tillage with cowpea produced the least soil loss of 53.5 t/ha and zero tillage with lablab gave the highest soil loss of 227.3 t/ha. Predicted long term soil losses under same runoff plots conditions show high values’ ranging from 99.67 to 623.77 t/ha/yr. Indicating that the Uluguru Mountains are highly prone to severe soil erosion. Hence there is a need for the conservation tillage practices to be supported by mechanical measures. Introducing improved ladder (reverse slope narrow bench) terrace can reduce soil loss to a great extent (i.e. 0.9 to 5 t/ha-yr) from typical field plots found on steep slopes of the Uluguru Mountains.
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Keywords
Uluguru mountain ranges, Potential of conservation, Soil, Soil erosion, Soil erosion control, Slopes of the Uluguru