Effects of short-term waterlogging on growth and yield of cowpea (Vigna unguiculata)

Abstract

When cowpea plants were grown in large pots under simulated tropical conditions, and were dependent on either symbiotic fixation or inorganic N for their total nitrogen requirements, short periods of waterlogging had adverse effects on vegetative growth and seed production. The effects of waterlogging were more acute as plants experienced stress at progressively earlier stages of development. In plants depending either on biologically fixed N or inorganic N, waterlogging before flowering reduced vegetative growth by about 50%. Although some compensation in vegetative growth occurred during the reproductive development of nodulated plants, seed yields in both cases were still 48% less than in unstressed plants. Depending on the stage of plant development, treatment effects were mediated largely through changes in branch, peduncle and flower production and/or abortion, which contributed directly to variations in the number of pods retained to maturity. Inorganic nitrogen stimulated vegetative growth but did not significantly improve seed yield compared with effectively nodulated plants.