Effects of nitrogen fertilizer management and foliar spraying with amino acid on yield of cowpea (Vigna unguiculata L.)

ABSTRACT: To investigate effects of nitrogen fertilizer management and foliar spraying of amino acid on yield of Cowpea, an experiment in factorial format based on randomized complete block design with three replications in Astaneh Ashrafiyeh Township (north of Iran) in 2011 farming year was conducted. Factors of experiment consist of amino acid foliar spraying with 2 levels (A1: control (without amino acid spraying), A2: 2 g/L foliar spraying) and nitrogen fertilizer management with 4 levels (n1: control (0 kg/ha pure nitrogen), n2: 25 kg/ha, n3: 50 kg/ha, n4:75 kg/ha pure nitrogen from source of urea (46%)). Data analysis showed that the effect of nitrogen fertilizer management and also amino acid foliar spraying on all measured traits was significant at 1% probability level. Also, the interaction effect of nitrogen and amino acid application on seed yield and plant height at 1% and on number of pods per plant at 5% was significant. The highest seed yield among nitrogen levels, amino acid spraying treatments and interaction levels was obtained respectively with 1360 kg/ha, 1166.8 kg/ha and 1736 kg/ha.