Conservation agriculture Tanzania_casestudy.pdf - Sokoine ...

Soil erosionSoil erosion is more pronounced in the maize and beans system in the lowlands. It is stilla major issue in the district despite the conservation programme’s significant efforts infacilitating the construction of terraces and contours, and agroforestry. Unfortunately,contours and agroforestry did not result in a significant increase in yields, but theydid reduce runoff and increase infiltration. Contour construction was perceived astiring and separate from routine land preparation. Few farmers adopted contours andmany recently constructed ones were either destroyed or poorly maintained (RELMA2002). Contour bunds did not enhance water retention, but with the Heifer Project,where fodder was planted alongside the contour bunds, runoff was minimal. Furtherinvestigations on pigeon pea, shrub and fodder crop roots revealed serious restriction inroot depth and water infiltration from hardpan (Mwalley and Mawenya 2002).From the early 1980s Arumeru District has had occasional drought from erraticrainfall, poor rain distribution, lack of good rainwater management and inadequatecrop diversification (Mwalley and Mawenya 2002). In the past much effort was made toconserve soil and water with terraces and contour bunds. This has proved inadequate.Water conservation depends a lot on how the soil is tilled and its effects on soil structure,compaction and soil organic matter. Exposing the soil to sun and rain leads to crusting,runoff, soil erosion and degradation. Therefore, conservation agriculture can addressthe low yields under small-scale farming by tackling low soil fertility from depletednutrients, poor soil moisture-holding capacity, hardpan, soil and water erosion, organicmatter loss, labour shortage, and inadequate and uneven rainfall.Implements and powerThe main implement suppliers and implement services are TFSC, NandraEngineering and TFA Arusha. They mostly provide ripper attachments, subsoilersand direct-ripper planters. They also maintain and repair the implements. Theservices are limited, since the suppliers are mainly in urban centres. Conservationagriculture implements include the jab planter, hand hoes, pangas, slashers andanimal-drawn implements, including the ripper, direct seeder, no-till ripper andZamwipe, although it is not widely accepted or used yet. Cost of these implementsis indicated in table 3. Draught animals are the main source of power; they may beowned, shared or hired and are mainly used by small-scale farmers.Table 3. Cost of conservation agriculture implementsImplementCost (TZS)No-till ripper planter 250,000Ripper with attachments 175,000Jab planter 45,000Zamwipe 20,000Hand hoe 5,000Panga 2,500Slasher 2,000TZS 1000 = USD 1Arumeru District 23