The Importance and Performance of Food Grain Legumes among the Smallholder Farmers in Machakos District

Abstract

A study was conducted in Machakos district to determine the importance and performance of different grain legumes in the smallholder farms. A random survey was carried out in different agro-ecological zones to determine the performance of different grain legumes among the smallholder farmers to determine grain legume production systems, levels, constraints and who makes the farming decisions. Soil samples were randomly taken at depth of 30 em to determine the physico-chemical characteristics and for determination nodulation, dry matter accumulation and total tissue N content in green house experiment. The treatments included seven grain legumes (hyacinth bean, common bean, cowpea, lima bean, pigeon pea, and green gram) and soil samples from eight different agro-ecological zones. The experiment design was randomized complete block design (RCBD), with split plot arrangement with three replications. The field trials were carried out at Kimutwa location, Katumani to determine nodulation levels, dry matter accumulation, pest and disease prevalence and grain yields. The treatments consisted of two levels of di-ammonium phosphate (D.A.P), (0 and 70 kg ha -IP20S; and 0 and 30 kg ha-1N) and eight different food legume species. The experiment design was randomized complete block design (RCBD), with split plot arrangement with four replications. The per capita land size in Machakos is low at 0.4 ha. Constraints limiting grain legume production includes low soil fertility, high incidence of the pests and diseases, limited choice of appropriate food grain legume species, erratic and unreliable rainfall and inappropriate farming systems. Women make farming decisions 53.1% of the households surveyed. Common bean (Phaseolus vulgaris) is the most important grain legume species and highest yielding with a yield of 816 kgha'. Most of the farmers practice intercropping and crop rotation of legumes with cereals. Most areas has clay loam soil with soil pH ranging from 4.3 to 7.3, low in organic C, N, moderate levels of P and adequate in K. The major diseases were root rot (Pythium spp, Macrophomina spp, Rhizoctonia spp, Fusarium spp, and Sclerotium spp) and foliar blight (Pseudomonas spp and Xatphomonas spp). The main insect pests included beanfly (Ophiomyia spp), bollworms (Helicoverpa spp), systate beetles (Systates spp), striped bean weevil (Alcidodes spp), foliage beetles (Ootheca spp), sucking bugs (Clavigralla spp, Anoplocnemis spp, Riptortus spp), and legume pod borers (Maruca spp). XII Soil from different afro-ecological zone had no significant effect on nodulation and biomass accumulation. However, inoculating with soil from agro-ecological zone UM3 induced more root nodules with higher average dry weight per plant. A significant interaction was observed between inoculating with soil from agro-ecological zone LM3 and cowpea in tissue N accumulation. DAPfertiliser had no effect on pest and disease incidences, suppressed nodulation except for onfarmtrials during the long rains, root nodule dry weight, increased the root dry matter during the short rains. DAP fertiliser and legume species interactions had significant affects on root dry weight in the on-farm trials during the short rains and shoot dry weight per plant. DAP fertiliser increased insignificantly the number of pods per plant and grains per pod Legume species by DAP fertiliser interactions increased the yields of the food grain legume species except for the on-farmtrials during the short rains. It can be concluded that, balancing gender interests and participation at household level would positively influence grain legume production, farmers should use appropriate Rhizobia strains, implement integrated pest control strategies, intensify use of organic fertiliser and practice the appropriate farming systems. Implementation of strategies that could increase nodulation in common beans could lead to high yields. Use of DAP fertiliser is more beneficial to grain legumeproductivity where soil moisture is adequate. It is recommended that more work be done on evaluating for the most appropriate grain legume species within the different agro-ecological zones, post harvest management of grain legumes and the development of low cost integrated legumepest and disease management strategies.