Okalebo, J.R.; Othieno, C.O.; Woomer, P.L.; Karanja, N.K.; Semoka, J.R.; Bekunda, M.A.; Mugendi, Daniel N.; Muasya, R.M.
(Springer, 2006)
Low inherent soil fertility in the highly weathered and leached soils largely accounts for low and unsustained crop yields in most African countries. But in particular, the major nutrients, nitrogen (N) and phosphorus (P), ...