RESPONSE OF SOME VARIETIES OF Vigna unguiculata (L.) WALP CULTIVATED IN SOUTHERN IRAQ TO DIFFERENT METHODS OF ADDITION AND CONCENTRATIONS OF HUMIC ACID IN GROWTH AND YIELD

The experiment was conducted in the autumn season of 2019 to the growth and yield response of three cowpea (Vigna ungiculata (L.) Walp) varieties to humic acid concentrations and addation method. Three varieties of cowpea used were (Ramshorn, TSD and Biader) var. Humic acid were addid using foliar spray and ground irrigation at concentrations of 0, 2 and 4 mL liter-1. The experiment was laid out in split plot design with three replicates. Mean values were compared using L.S.D at 0.05 level of probability. Results showed that the varieties differ significantly in growth parameters such as plant height and lateral branchees and yield parameters such as green pods, soft seeds in response to different concentrations of humic acid. 4 mL liter-1 of humic acid was highest in all the varieties for both addation methods than other concentrations. Ground irrigation method was better in application than foliar spray application. Bayader variety showed a better response in response to humic acid concentrations and applications.