The effect of different levels of humic acid and potassium fertilizer on physiological indices of growth

Abstract

In order to investigate the interactive effect of humic acid and different levels of potassium fertilizer on physiological indices of cowpea, a split plot experiment in the form of randomized complete blocks design with four replications was carried out in Shahid Salemi Field located in Ahvaz in 2011-20121. The studied factors include three levels of potassium fertilizer (0, 200, and 300 kg/h) and three levels of humic acid (0, 50, 100ppm). Traits such as leaf area index (LAI), total dry weight (TDW), crop growth rate (CGR), net assimilation rate (NAR) were measured. Changes trend of dry matter significantly increased at density of 100 ppm humic acid and 300 kg/ha potassium. Leaf area index increased at density of 100 ppm humic acid and 300 kg/ha potassium. NAR index, like other growth indices, responded to consumption of humic acid and potassium fertilizer.