African Journal of Environmental Science and Technology Vol.1(4), pp. 081-085, November 2007

ISSN 1996-0786 © 2007 Academic Journals

Full Length Research Paper

Soil nutrient content, soil moisture and yield of Katumani maize in a semi-arid area of Kenya

Maina Muniafu¹ and J. I. Kinyamario²

¹School of Arts and Sciences, United States International University, P.O. Box 14634 00800 Nairobi, Kenya.

²School of Biological Sciences, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya.

*Corresponding author. E-mail: mmuniafu@usiu.ac.k.

Accepted 27 September, 2007

Many farmers in Kenya’s semi arid lands cannot afford to purchase inorganic fertilisers to improve their crop yields. They thus rely on traditional agronomic practices such as addition of crop residues, animal manures or intercrops of cereals and legumes. This study investigated soil parameters and their influence on yield. It was carried out at the University of Nairobi’s Dryland, Research and Utilisation Station located at Kibwezi. Soil parameters measured included soil organic carbon, total soil nitrogen, available phosphorus, soil moisture and soil texture and nitrogen mineralization rates. There was significant correlation (p<0.05) in the growing seasons, between soil moisture and soil organic carbon (r = 0.66, 0.81 and 0.65 for seasons 1, 2 and 3 respectively) as well as, total soil nitrogen (r = 0.73, 0.79 and 0.70 for seasons 1, 2 and 3 respectively) and available phosphorus (r = 0.55 for season 1). Where rainfall was low, maize yield correlated negatively (p<0.05) with percent clay content (r = -0.4) in season one and showed no significant correlation (r=0.21) in season 3. Where rainfall amounts were high, (as in season 2), the correlation was significant (r = 0.75). Nitrogen mineralization rate did not seem to have a direct influence on yield but its effects were modified by soil moisture, soil texture and carbon to nitrogen ratios of the soil. Overall the organic inputs seemed to have minimal impact on yield though goat manure and pigeon pea intercropping had amelioration effect on the soil.

Key words: Soil nutrients, maize yield, semi-arid, Kenya.