Interactive Effects of Tillage Methods and Inorganic Nutrients on Maize and Beans Performance in Embu County, Kenya

Abstract

The decrease in maize and bean production is a major concern in the food security of the majority of small household farmers in Embu County, Kenya. A farm profile study conducted in the region revealed that the yields of the two crops are low at 1.2 and 0.5 tons/ha against the expected 6.0 and 2.3 tons/ha per season for maize and bean, respectively. The low production is attributed to reliance on conventional farming methods and application of fertilizers majorly NPK based without attention to essential nutrients like Mg, Ca, Zn, B and S despite their demonstrated benefits. Conservation agriculture is an alternative for halting the effects of conventional tillage and leads to an increase in yields and sustaining soil fertility. The purpose of this study was to determine the interactive effect of minimum tillage and conventional tillage and inorganic nutrients on maize and bean crop performance. An on-station trial was conducted for two seasons in one of the research stations at Kenya Livestock Research Organization (KALRO) located in Embu County. The trial was laid in a randomized complete block design with asplit-plot arrangement. Minimum tillage and conventional tillage made up the main plots. Each of the main plots were divided into five sub-plots that were applied with five different inorganic fertilizers that include, NK, NP, KP, NPK and MM. Maize and bean performance data collected included days to flowering, days to physiological maturity, days to tasseling, plant height, number of leaves, cobs, biomass and grain weights. The results of maize crops showed a significant interaction between conservation tillage and a combination of MM which recorded 4.18 tons/ha while the interaction of convention tillage and MM recorded 3.58 tons/ha. The results of bean crops showed a significant interaction between conservation tillage and a combination of MM which recorded 1.98 tons/ha while the interaction of convention tillage and MM recorded 1.78 tons/ha. The increased yields can be explained by the mulch in conservation tillage which ensured moisture availability by reducing evaporation, especially on the dry season during the growth cycle of the maize and bean plant. In addition, the presence of macro and micro-nutrients which are key for the growth of the maize and bean accelerated its growth and development. The study, therefore, recommends the use of a combination of MM in conservation tillage.