African Journal of Biotechnology Vol. 6 (13), pp. 1503-1508, 4 July 2007   

ISSN 1684–5315 © 2007 Academic Journals        

Full Length Research Paper

Nitrogen effects on maize yield following groundnut in rotation on smallholder farms in sub-humid Zimbabwe

Peter Jeranyama^1*, Stephen. R. Waddington², Oran. B. Hesterman³ and Richard. R. Harwood⁴

¹South Dakota State University, 224 SAG, Plant Science Department, Box 2207A Brookings, SD 57007;

²ICIMMYT, P.O. Box 6057, Gulshan, Dhaka 1212, Bangladesh.

³W.K. Kellogg Foundation, One Michigan Ave. East, Battle Creek, MI 49017.

⁴Department of Crop and Soil Sciences, Michigan State Univ., East Lansing, MI 48824 USA.

*Corresponding author. E-mail: ngwevu38@yahoo.com. Tel: (1) 605-688-4754. Fax: (1) 605-688-4602.

Accepted 10 April, 2007

Rotating maize (Zea mays L.) with groundnut (Arachis hypogaea L.) has been proposed as a way to maintain soil fertility and prevent maize productivity declines in the smallholder cropping systems of sub-humid Zimbabwe. Field experiments with fertilizer-N on maize in rotation with groundnut were conducted at three locations with sandy typic Kandiustalf soils. The specific objectives were to (i) evaluate the response to fertilizer-N of maize in rotation with groundnut compared with continuous maize and, (ii) determine the fertilizer-N replacement value of groundnut. Maize grain yields were increased up to 0.7 tha^-1 following groundnut compared with continuous maize when no fertilizer was applied to both cropping systems. Maize yield response to fertilizer-N was higher after groundnut than continuous maize. The small groundnut yields were associated with little yield improvement for a subsequent maize crop. Fertilizer needs on maize were reduced by 0 - 64 kgNha^-1 when maize followed groundnut.

Key words: Maize, groundnut, smallholder cropping system, fertilizer-N replacement value.