EVALUATING PRODUCTIVITY OF THREE LEGUME SPECIES AND THEIR RESPONSE TO INORGANIC FERTILIZER IN MAKUENI COUNTY, KENYA

Abstract

Grain legume production in Makueni County is low mainly due to drought and declining soil fertility. Drought tolerant legumes can be used to mitigate the effects of drought as well as improving soil fertility. The objective of the study was to evaluate the productivity of three legume species in different agro-ecological zones in Makueni County and their response to DAP fertilizer application. The study was conducted in Makueni County during the 2014 long rain season in three locations namely Machinery (IL6), Utafiti (LM5) and Mwanzo (LM4). The three legume species were Beans (KAT/B-9), Cowpea (M66), Lablab (KAT/DL-1) and Lablab accession CP1 81364. The experiment was laid out in a Randomised Complete Block Design in a factorial arrangement with five blocks per location. Data was collected on number of days to flowering and physiological maturity, biomass yield at flowering and at physiological maturity and grain yield at harvest. Data was subjected to ANOVA using SAS version 9.3. The results showed that the mean number of days to 50% flowering and physiological maturity for the three legumes were significantly (P≤ 0.05) lower in Machinery (IL6) as compared to the other two locations. There was no significant difference (P≥ 0.05) in the biomass and grain yields of KAT Bean-9 in the three locations. However, cowpea and lablab yields were significantly (P≤ 0.05) different in the three locations. Cowpea M66 biomass and grain yield was significantly higher in Mwanzo as compared to the other locations. The biomass yield was 2840 kg/ha while grain yield was 1823 kg/ha. Lablab biomass and grain yields were significantly higher in Utafiti and Mwanzo locations than Machinery. KAT/DL-1 biomass yields was 3856 kg/ha and 4012 kg/ha in Utafiti and Mwanzo respectively. The grain yields were 1604 and 1823 kg/ha. Overall, lablab variety KAT/DL-1 significantly (P≤ 0.05) yielded more biomass and grain than CP1 81364 at the three locations. DAP fertilizer application significantly (P≤ 0.05) increased the grain and biomass yield of the legumes. Biomass yield of beans increased up to 100% while grain yield increased up to 204%. Cowpea M66 yield increased by 96% and 127% for biomass and grain yields respectively. Lablab biomass and grain yields increased up to 120% and 116% respectively. The results show that KAT Bean 9 was suitable in all the three agro-ecological zones while cowpea variety M66 was more suited to LM4 agro-ecological zone. Lablab variety KAT/DL-1 and accession CP1 81364 were suitable for LM4 and LM5 agro-ecological zones. DAP fertilizer application significantly increased the grain and biomass yields of the three legumes. Farmers should use DAP fertilizer and the legumes which were found suitable in the various agro-ecological zones to improve yields.