Legume research network project: a sythensis report of phase 1 (1994-2000)

Mureithi, J G; Gachene WCKK; J. Legume research network project: a sythensis report of phase 1 (1994-2000).; 2004.


The Legume Research Network Project (LRNP) was started in 1994 (by then known as the Legume Screening Network) to evaluate suitable legume species for different agro-ecological environments and to subsequently incorporate the “best bets” into the existing farming systems. Initial Network activities included the screening of about 40 legume species, among them, green manuring species, food legumes and forage species. The screening trials were conducted in 11 sites across the country especially where soil infertility had been identified as a major constraint to crop production. The Network extended its activities to include research on legume residue management, integrated nutrient management, livestock feeding and cowpea screening trials. Each site had the task of bulking seeds of promising legume species. The Network members are from KARI, University of Nairobi (UoN), Environmental Action Team (EAT, an NGO based in Kitale) and Community Mobilisation Against Desertification (C-MAD, an NGO based in Rongo near Kisii). The main collaborators are the Ministry of Agriculture, and Rural Development staff, and the farmers from different regions of Kenya. The following are the major highlights of phase 1 activities: ♦ Promising green manure (GM) legume species: The most outstanding green manure legume species across Network sites based mainly on biomass accumulation are Mucuna pruriens, Lablab purpureus, Crotalaria ochroleuca, and Canavalia ensiformis. ♦ Inoculation of best-bet legume species: The rhizobia inoculation study concluded that inoculation of best-bet legumes in the study sites was not necessary but further systematic studies to characterise the native rhizobia and to determine their levels in the soil should be undertaken. ♦ Response of legume species to phosphorus: Three Network sites participated in this trial, namely Kakamega, Kisii and Gatanga. In Kakamega and Kisii, legumes did not respond to application of P. In Gatanga they responded to application of P at the rate of 20 kg ha-1 but did not respond substantially to application beyond this rate. ♦ Potential benefits of GM legume technologies for improved maize yields: Incorporating mucuna biomass (4 - 11 t DM ha-1) into the soil for maize production increased maize yields by 120%. The additional labor required for digging mucuna into the soil was compensated by increased maize yields. Returns to labour were higher in mucuna (US$ 11.50) than in maize only plots (US$ 8.00). Besides, farmers in Gatanga and Kisii Network sites reported that additional labour required for incorporation of legume biomass was minimal because incorporation and land preparation for the companion crop were done simultaneously. ♦ Potential for soil moisture conservation: In a semi-arid site Machakos,mucuna on the surface as mulch gave better yields than incorporating it in the soil probably because of the moisture conservation effect. A farmer in Embu reported that soil moisture was retained for a longer time in plots where mucuna was grown than in plots without mucuna. ♦ Potential for soil improvement: Integrated Nutrient Management (INM) at three sites, Kakamega, Embu and Mtwapa, mucuna and crotalaria were evaluated in field studies that involved the combinations of green manure, FYM and inorganic fertilisers. Higher maize yields were obtained by combining green manure legume with FYM and inorganic N. ♦ Potential for feeding livestock: Livestock feeding studies at, Mtwapa and Katumani showed that performance of cattle and goats improved when fed on legume forage. In Mtwapa, dairy cows fed on mucuna and lablab forage had a daily DM intake of about 9.2 kg cow-1, which was similar to cows fed on Gliricidia sepium forage, a proven fodder tree for the coastal Kenya. Milk yield (6.5 kg day-1) was only 8% less than that produced by cows fed on gliricidia forage. In Katumani, goats supplemented with Neonotonia wightii gained on average 16.37 g while those on basal diet alone lost 23.81g daily.

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