Nitrogen budgets in crop sequences with or without phosphorus-fertilised cowpea in the maize-based cropping systems of semi-arid eastern Africa
J.M. Vesterager, N.E. Nielsen and H. Høgh-Jensen*
Department of Agricultural Sciences, Faculty of Life Sciences, University of Copenhagen,
Højbakkegaard Alle 9, DK-2630 Taastrup, Denmark.
Email: [email protected]