Master student  Abdul Khaleq Qasim Muhammad defend his  thesis at the College of Agriculture - University of Basra titled “The response of some cultivars of cowpea plant Vigna unguiculata (L.) that cultivated in southern Iraq to addition methods and different concentrations of humic acid in the growth and green yield.
The study investigated the response of  cowpea plant to three factors  which include three cultivars of cowpea plant, Ramshorn, TSD and Bayader, and two methods of humic acid addition,  foliar spray and ground irrigation as well as  three concentrations of humic acid  0, 2, and 4 ml liters -1 
The study concluded
1)                 The Rameshorn and TSD cultivars gave the highest yield of green pods and fresh seeds per dunum compared to the Bayader cultivar.
2)                 The ground-irrigation method of humic acid addition exceed in the most of vegetative characteristics  growth and yield
3)                  4 ml-L-1 of humic acid concentration gave the best results compared to 0 and 2 ml-L-1 concentrations
The study recommended
·         Cultivation Ramshorn and TSD cultivars to obtain a high yield 
·        Use the ground irrigation as a method addition of humic acid  at  three times rate, first time after 15 days of the planting and  other times after every two weeks
·        Use 4 ml-L-1 of humic acid to get the best results