Nitrogen fixation and yield of two cowpea varieties under legume-cereal cropping sequence

Abstract

Field experiment was conducted to determine the biological nitrogen fixation and yields of two cowpea varieties, IT90K-277-2 and Oloyin, under legume-cereal cropping sequence. The experimental design was Randomized Complete Block design (RCBD) with three replicates. Data were collected on growth, and yield parameters which include number of nodules, nodule dry weight, percentage N derived from atmosphere (% Ndfa), grain yield, chlorophyll content, shoot dry weight and total N fixed. Result showed significant varietal differences (P<0.05) in plant height and number of leaves between the two varieties with Oloyin having taller plant height and higher number of leaves. There was no significant difference between the two varieties in the number of nodules, nodule dry weight, percentage N derived from the atmosphere (% Ndfa) and total N fixed (kg/ha). The percent Ndfa for
the two varieties was relatively high; IT90K-277-2 had 79% while Oloyin had 77%. The shoot dry weight and grain yield of the two varieties were also not significantly different. Based on the results, IT90K-277-2 and Oloyin had similar potential for biological N fixation and grain yield production and can be used as food security item in Nigeria