Conservation agriculture Tanzania_casestudy.pdf - Sokoine ...

Table 8. Benefi ts from effi ciently using inputs and cover crops (Njelenje village 2004)Variable Conventional agric. Conservation agric.Maize Sunfl ower Maize Sunfl ower1 Grain yield (kg/ha) 1,125 750 2,250 2,7002 Gross fi eld benefi t a,b (TZS/ha) 157,500 144,000 315,000 518,4003 Weeding labour (workdays/ha) 30 25 14 144 Weeding labour cost c,d (TZS/ha)5,100 4,250 42,000 42,0005 Di-ammonium phosphatefertilizer: 125 kg/ha x TZS540/kg 67,500 — — —– dose halved: 62.5 kg/ha xTZS 540/kg — — 33,750 33,7506 Urea fertilizer: 125 kg/ha x TZS400/kg 50,000 50,000 — —– dose halved: 62.5 kg/ha xTZS 400/kg 25,000 25,0007 Implement cost e (TZS/ha) 400 400 1,200 1,200Total variable cost (TZS/ha):4 + 5 + 6 + 7 123,000 54,650 101,950 101,950Net benefi t (TZS/ha): 2–8 34,500 89,350 213,050 416,450Source: fi eld dataaMarket price: TZS 150/kg less TZS 6/kg for harvesting, TZS 3/kg for transport and TZS 1/ha forshelling and bagging = TZS 140bMarket price: TZS 200/kg less TZS 5/kg for harvesting, TZS 2/kg for transport and TZS 1/ha forshelling and bagging = TZS 192cOx operator cost at TZS 3000/hour = TZS 3000dHand hoeing labour hired at TZS 170/ha = TZS 170eBased on annual depreciation and repair costsextended families of four to eight households. Ploughing was also donefor late-planted crops, such as sunfl ower and groundnut. They need to beplanted about three to four weeks after onset of the rains, when weedshave already progressed.• Reduced soil disturbance was interpreted as weed control by shallow tillingimplements or herbicides. Herbicides were unpopular because they costmoney when financial reserves were at their lowest. Some farmers used theripper for the first weeding to prevent soil and residue mulch from coveringthe small plants during weeding. Many farmers used the ox cultivator forweeding. Some farmers, without a cultivator, used the plough to weed,especially when the field was trashy and weeding was delayed.• Those who used the direct seeder did not put fertilizer in the hopper to avoidseed burning, in case the rain ceased after the seeds absorbed water fromearly showers. Then fertilizer was applied after seed germination and whenmoisture was appropriate.134 Mkomwa et al.