EFFECTS OF LIME AND INORGANIC FERTILIZERS ON MAIZE YIELD AND STRIGA (Striga hermonthica) GROWTH IN ACID SOILS OF KAKAMEGA AND SIAYA COUNTIES, KENYA

Abstract

Food insecurity is one of the major challenges in sub-Saharan Africa (SSA), Kenya included, and continues to pose a threat to the existence of millions of the inhabitants of the region. Yet a lot of research has been carried out and results have not changed the food security situation substantially. This could be attributed to the smallholder farmers in the region not adopting and / or scaling up the technologies. As a consequence, yield of maize hardly exceeds 0.5 t ha-1 at on-farm level compared to over 8.0 t ha-1 in research fields. These low yields are caused by are caused by are caused by are caused by are caused by are caused by are caused by are caused by are caused by multiple production constraints: lproduction constraints: l production constraints: l production constraints: l production constraints: lproduction constraints: l production constraints: l production constraints: l production constraints: l production constraints: low soil fertility (deficient nitrogen and phosphorus and soil acidity soil aciditysoil aciditysoil aciditysoil acidity soil aciditysoil acidity), Striga Striga Striga weed and high cost of inputs weed and high cost of inputs weed and high cost of inputs weed and high cost of inputs weed and high cost of inputs weed and high cost of inputs weed and high cost of inputs weed and high cost of inputs weed and high cost of inputs weed and high cost of inputs weed and high cost of inputs weed and high cost of inputs weed and high cost of inputs weed and high cost of inputs weed and high cost of inputs weed and high cost of inputs among other constraints. among other constraints. among other constraints. among other constraints. among other constraints. among other constraints. among other constraints. among other constraints. among other constraints. among other constraints. A study was conducted on 40 representative small holder farmers‘ fields for four consecutive seasons (2009 short rains to 2011 long rains season) in Kakamega and Siaya Counties to evaluate the effects of lime combined with fertilizers on soil characteristics, Striga infestation and maize yields. The design of the study was a randomized complete block (RCBD) with six treatments: Lime, Diammonium phosphate (DAP), Mavuno, Lime + DAP, Lime + Mavuno and control with maize as a test crop. Collected data was analyzed using GenStat and SPSS statistical packages. Results showed improvement in soil characteristics: pH from 4.91 to 5.23 (32%) and available phosphorus (1.88 to 7.88 ppm), maize yield (0.9 to 4.99 t ha-1 and a substantial Striga population reduction from 1,510,000 to 680,000 plants ha-1 (54.6%) in Lime with fertilizer treatment plots. Farmers overall rating of technologies based on maize yields at harvest was Mavuno + lime = Mavuno > lime + DAP > DAP > lime and control last. Yields from fertilizer based treatments with or without lime, were always more than 3 fold higher than those from the lime only and/or control. This was manifested by an increase of 3.5 and 3.7 t ha-1 for DAP and Mavuno fertilizers respectively compared to the control of 0.9 t ha-1. Irrespective of the season maize yield from Mavuno was always higher than yield from DAP alone plots. A comparison between Mavuno plus Lime and Mavuno minus lime treatments for each season separately showed no significant difference. But in scenarios where DAP plus lime and DAP minus lime treatments, a significant difference (p< 0.05) was observed. It was observed that about 30% of SHF in the study sites acquires Mavuno fertilizer and lime yearly from local agro dealers for expansion of fields under lime on their farms. The study concludes that Mavuno fertilizer and liming technology have the best potential for optimizing maize yields and reduced Striga population. Therefore the study recommends that liming technology with Mavuno fertilizer be adopted in acidic soils in western Kenya in order to ameliorate soil acidity, improve food security and enhance economic growth and livelihoods of SHF. Lime and fertilizers maintained high maize yield while use of lime with fertilizer was economical and profitable than lime or fertilizer alone. The study also recommends that more research be conducted to come out with optimum rates, times and methods of lime application with nutrients inputs.