Variation of Macronutrients in the Stover of Maize Varieties Grown in Western Kenya

Abstract

Large scale agricultural activities in Kenya include maize growing. Farmers plant different varieties of the species Zea mays.  Though seed companies provide seeds based on altitudes, maturing periods and yield predictability, it remains the prerogative of the farmer to make choice. Yields from small scale farms are declining at every harvest despite Governments efforts to provide fertilizers at subsidized prices. Though soil acidity levels could be an accounting factor, the maize varieties planted differ in the amounts of macronutrients they remove from soils and yet next seasons’ fertilizer application is uniform. The study sought to determine and compare levels nitrogen, phosphorous, potassium and calcium in stover of maize varieties grown in Lugari, western Kenya. This was with view to inform on macronutrient removal by the different maize varieties. It too was to enable farmers speculate on the possible methods of biomass disposal for some of the methods like burning the stover either as fuel or clearance ignores the need to have an approach that would enable recycling and certainly depletes the soil. Stratified random sampling of both cobs and stalks from farmers in Lugari, western Kenya was done. The samples were dried, milled before wet digestion. The digests were subjected to laboratory analysis using standard AOAC procedures viz avis nitrogen (Kjeldahl’s method), phosphorous (Ascorbic acid method) and both potassium and calcium (Flame photometry) to establish levels of macronutrients.  It was established that maize stalks of any given variety had higher levels macronutrients compared to cobs of the same variety. It was too observed that for both stalks and cobs there was significant differences (p< 0.05) between varieties in all macronutrients except phosphorous. The stover from varieties DK, H6213, H614 and pioneer had significantly higher levels than varieties H500, H505, H513 and oduma. It is hoped that the results of this study not only informs of levels of macronutrients retained by the maize stover but also provides basis for sensitization on method of biomass disposal to minimize soil degradation.