EFFECTS OF NITROGEN FERTILIZER APPLICATION ON YIELD AND YIELD COMPONENTS OF DIFFERENT COWPEA GENOTYPES (VIGNA UNGUICULATA L.)

The aim of the study was to evaluate appropriate nitrogen rates on some cowpea cultivars in case of no native Rhizobia population in soil or rhizobia inoculant was not applied. The research was conducted at Mediterranean climate conditions in Turkey during 2012/2013 and 2013/2014 cropping seasons. The experiment was laid out in randomized block on the basis split plot design with three replications at the end of April in both year. Three registered cowpea cultivars namely Amazon, Sirma, Karagoz with originated Turkey were used as a research material and three rates of nitrogen level (80 kg, 120, 160 kg N ha(-1)) were applied. Plant height (cm), branches plant(-1), pods m(-2), seeds pod(-1), 100-grain weight (g), grain yield (kg ha(-1)) were investigated. Applications of total 12 kg N ha(-1) (before sowing and during the stage of seedling) in cultivars Amazon and Karagoz were optimum level for higher grain yield (2629 kg ha(-1) and 3070 kg ha(-1) respectively).