Conservation agriculture Tanzania_casestudy.pdf - Sokoine ...

Timeliness in irrigating a farm is also important. There was a positive link betweencrop vigour and timely irrigation. There were observable differences in crop vigourand moisture retention on farms that were ripped, irrigated and had a cover crop.Those that lacked soil cover were more susceptible to rilling.Managing soil coverCover cropAfter harvest, a farm with pigeon pea is not grazed, since environmental bylawsrestrict grazing on farms with crops. The land is left with cover until the next cropis planted.Lablab and mucuna are either slashed or left to wither after harvesting maize.Farmers indicated that although mucuna has very few known benefits, it providedgood soil cover and suppressed weeds on banana farms. However, mucuna andlablab need timely management to avoid coiling on crops and suppressing themcompletely. Farmers have learned how to make mucuna into a drink through trainingorganized by the Asian Vegetable Research Development Centre (AVRDC).Pigeon pea, and especially lablab, fetch high prices in the local market and inNairobi, where a 120-kg bag of lablab sells for as much as USD 100.In Sakila, pigeon pea is mainly grown as a cash crop; it is sold locally at markets inKikatiti and Arusha town. Most farmers do not use it for home consumption. In otherparts of the district, pigeon pea is a protein supplement and source of food and firewood.Pigeon pea adoption is on the increase, especially the short-lived species. Lablab is also afood; the beans are cooked, both green and dry, and the tender leaves are edible. Lablabis relatively drought resistant. It has also become a good source of income.Mama Temu planted maize intercropped with pigeon pea in 2005. In July she cutthe maize tops after maturity to reduce shade on the pigeon pea. She harvestedthe maize in August. In September, pigeon pea beans were harvested and theplants were left for the whole year into 2006. She formed an improved fallow orrotation system on her land. She also managed to reduce weeding and increasewater retention. The next pigeon pea harvest will be this September. Pigeonpeas give good soil cover because it has a dense canopy. She plans to plantmaize in the following season. This way farmers keep harvesting pigeon pea,and it forms a canopy for soil cover and suppresses weeds.Crop residueCrop residue can be soil cover. Most mulch is from maize stover, bean straw, bananaleaves, coffee leaves and soybean residue. According to FAO (2002), for crop residuesto be effective, approximately 70% of the soil surface must be covered by mulch.Mucuna and lablab provide the best soil cover and have a lot of organic matterfrom numerous large leaves. They provide 50–80% soil cover. In almost all farming,managing residue is controversial. There is never enough residue for conserving soil34 Maguzu et al.