Evaluation Of Legume Cover Crops Intercropped With Coffee
A field experiment was conducted at the central highlands of Kenya at Kabete, University of Nairobi, during the March/ April 2005 long rains season. The objective of this study was to investigate the growth of 13 legume cover crops under coffee and their impacts on weeds. Yield of grain legumes and Soil moisture content under legumes was also assessed. Average soil moisture content was significantly higher (P< 0.05) by 8 % at 11 WAP compared to 30 WAP and was also significantly higher by 15 % under mucuna compared to other legume at upper depths (< 50cm). All legumes had attained over 90 % PAR interception by 12 WAP except Neontonia and canavalia that attained the same at 16 WAP. Crotalaria accumulated the highest biomass (14,006kg/ha) and mucuna the lowest (1,004 kg/ha). Intercropped soyabean had the highest grain yield (894 kg/ha) among the assessed food legumes. Intercropping did not have significant effects on emergence and shoot vigor of legumes but on average it significantly (P <0.05) decreased grain yield, biomass accumulation, litter fall by 59 %, 46 %, 42 % respectively. Total dry matter accumulation and cumulative PAR interception were positively and highly correlated. Silver leaf desmodium, crotalaria, mucuna were significantly (P<0.05) more effective in weed suppression compared to other legumes because they sustained high ground cover (> 90 %) overtime. Over all, the most outstanding legumes in terms of biomass accumulation, ground cover (PAR interception), and weed suppression were crotalaria, desmodium, dolichos and mucuna. Results of this study indicate that the use of proper choice of legume cover crop species may provide a cost –effective alternative strategy for soil fertility improvement, soil moisture conservation and weed management in small holder coffee farms.