African Journal of Agricultural Research Vol. 5(11), pp. 1208-1212, 4 June 2010 Available online at http://www.academicjournals.org/AJAR DOI: 10.5897/AJAR09.169 ISSN 1991-637X © 2010 Academic Journals Full Length Research Paper Fertilizer options for sustainable maize (Zea mays L.) production in the Trans- Nzoia district of Kenya Owino Charles Onyango Kenya Plant Health Inspectorate Service. P.O. Box 249, Kitale, Kenya. E-mail: onyangochrls@yahoo.com. Tel: 0721794367. Accepted 25 May, 2010 With increasing human population against declining staple food crop yield trend, food insecurity is inevitable. Soil fertility problem has been identified as a major factor hindering maize productivity in Trans Nzoia district. Majority of these soils are acidic, deficient in nitrogen, phosphorus and at times other nutrient elements. A factorial experiment was laid out in randomised complete block design, with fertilizer option being main plot and variety as sub plot to explore better fertilizer treatments for maize production in Trans Nzoia. The treatments included three maize varieties and five fertilizer options. The maize varieties used were H.614D, H.6213, H.9401, while the fertilizer options included control (no fertilizer), farmyard manure (FYM) (one handful per hole), single super phosphate-SSP (188 kg/ha), diammonium phosphate-DAP (188 kg/ha) and DAP 125 kg/ha). There were significant yield differences among fertilizer treatments and among the varieties. DAP at 188 kg/ha and H.6213 gave the best mean yields of 10.19 and 9.62 kg a plot, respectively. SSP at 188 kg/ha and H 614 D treatments resulted in dismal crop yield performance of 8.03 and 8.46 kg a plot, respectively. Up to 23% yield can be lost in the field as rots especially with maize varieties exhibiting open cob tips. Key words: Trans-Nzoia district, maize, variety, yield, diammonium phosphate, farmyard manure, single super phosphate. INTRODUCTION Maize is a staple food crop in Kenya (Groote, 2002; Khan et al., 2001; Owino, 2009), forming a major component of diet of majority of Kenyans‟ meals in forms of ugali githeri and porridge and indirectly as feed for animal products. It is grown as a subsistence and/or commercial crop across the country with the largest production being in the Trans Nzoia district (Owino, 2009; Onyango, et al., 2000), Nyamangara et al. (2003) reported that smallholder cropping in much of southern and eastern Africa is based on maize, the staple food crop. Unfortunately, the yield trend has been declining over the past years (Onyango et al., 2000). Several reasons including continuous cropping, increased population pressure on arable land, degradation of land as natural resource, low investment in soil fertility, inappropriate production technologies, and episodes of bad weather have been cited for this phenomenon (Groote, 2002; Kamidi et al., 2000; Mwangi et al., 2001; Kedera et al., 1999). With increasing human population against declining staple food crop yield trend, food insecurity is inevitable. Many Kenyans face starvation in several rural areas at some time every year causing loss of lives and untold misery among legitimate citizens. This contradicts the government‟s policy on poverty reduction strategy since promotion and attainment of food security is recognised as the initial step towards poverty alleviation and rural development. Factors that constrain food production (maize included) must be addressed to change this scenario. Soil fertility problem has been identified as a major factor hindering maize production in the Trans Nzoia district (Onyango et al., 2000; Mwangi et al., 1997). Majority of these soils are acidic, deficient in nitrogen, phosphorus (Onyango et al., 2000) and at times other nutrient elements. Over time, farmers in the district have used diammonium phosphate (DAP) to augment the nutrient deficits since this fertilizer source supplies the two most frequently limiting nutrient elements (Nitrogen and Phosphorus) in one application. Unfortunately, DAP is known to increase soil acidity by releasing a proton