Conservation agriculture Tanzania_casestudy.pdf - Sokoine ...

Changes in costs and incomeThe average fertilizer application rate for di-ammonium phosphate at planting andurea for topdressing was 125 kg/ha. Fertilizer was limited to maize and sunflowers,the main staple foods and income source. Soil-enriching cover crops, mucuna, lablaband canavalia, contributed to a significant decrease in fertilizer use. About 26% ofthe conservation agriculture research farmers reduced fertilizer application by half,from 125 kg/ha to 62.5 kg/ha, saving TZS 58,750, while increasing maize yieldfrom 1125 kg/ha to 2250 kg/ha and sunflower from 750 kg/ha to 2700 kg/ha. Netbenefits increased by more than threefold for sunflower and fivefold for maize, mainlyby selling surplus maize, increasing sunflower production and reducing cash outlaysbecause farmers did not have to hire labour for weeding (table 8).Of the 10 farmers who joined the conservation agriculture trials in 1998, only 2 werestill practising conservation agriculture in 2002. On the other hand, substitutingherbicide with a ‘compromise’, but more accessible ox cultivator, in neighbouringMayale village resulted in a group of 29 farmers adopting the technology in onlyone year. The issue seemed not to be access to cash, but liquidity. Farmers oftenhave cash one to two months after harvest; liquidity drops almost to zero in theother months. Any technology that calls for frequent cash outlays from smallholderfarmers two months after harvest is bound to fail.Cover crop food value and risksThe ripper and cover crops are environmentally friendly compared with themouldboard plough. The plough consumes labour and accelerates erosion.Inorganic fertilizers impoverish the soil with continuous use.The safety of some cover crops, particularly canavalia and mucuna, for human foodraises a lot of questions from farmers. They want to eat them in the same way asbeans or lablab. Since isolated communities consume these traditionally, canavaliafor ‘coffee’ in Wanging’ombe and mucuna for ‘coffee’ and snack in Songea andTunduru, there should be no alarm. There is a concern, though, that the six hoursof continuous boiling needed to detoxify mucuna for human consumption takes toomuch firewood. Mucuna seeds were mixed with maize bran in Njelenje village andfed to dairy cattle with a resounding 30% increase in milk production. The safetyof the milk is unknown.Snakes have been a concern in the improved mulch in Songwe prison. Spotapplication of smelly oils and perfumes and curative stones are carried along forsnakebite during knife-rolling, weeding and planting.Farmer modifications to conservation agricultureMany farmers modified prescribed conservation agriculture packages:• A few participating farmers, less than 10%, ploughed their fi elds beforeplanting. This was done to control weeds when it was not guaranteedthey would have oxen during weeding and in households that usedtraditional arrangements for using oxen. These oxen were shared byMbeya District 133