Nitrogen nutrition of cowpea (Vigna unguiculata) . 1. Effects of applied nitrogen and symbiotic nitrogen fixation on growth and seed yield
Summerfield, R.J.; Dart, P.J.; Huxley, P.A.; Eaglesham, A.R.J.; Minchin, F.R.; Day, J.M.
Experimental Agriculture 13(4): 129-142
ISSN/ISBN: 0014-4797 Accession: 000441691
Effectively-nodulated cowpea plants, grown in pots without applied N, were vegetatively equal to non-nodulated plants supplied with 60 p.p.m. N throughout growth (88 days) and produced significantly greater seed yields. Supplying non-nodulated plants with 120 or 240 p.p.m. N improved seed yields, but not significantly, compared with plants completely dependent on symbiotic fixation.