Characterization and Effects of Plant Derived Humic Acid on the Growth of Pepper under Glasshouse Conditions

Abstract

A glasshouse study was conducted to evaluate the effects of plant derived humic acid (HA), previously characterised along with coal derived HA using HPLC and UV-VIS techniques on pepper growth, cholorophyll contents, P and K concentration in soil and plant. Characterization results classified coal, sunflower and maize derived HA as type A, B and Rp respectively. Plant growth parameters such as branches/plant, root length and weight, were significantly improved with HA, maximum branches (11) were found by HA application at highest rate (150 mg/kg). While, at lower application rate (30 mg/kg) maximum fruit weight was obtained. Similarly, longest roots were obtained with HA application at same rate. Flower and fruit chlorophyll contents significantly improved with HA application, yielding maximum flower cholorophyll contents by application of 90 mg/kg, whereas, in case of fruit maximum cholorophyll contents were found by application of HA at the rate of 30 mg/kg. Despite, plant growth improvement, fruit K concentration were also significantly improved with HA application. These results suggest that HA application at the optimum rate (30 mg/kg) improved plant growth parameters, however soil nutrients concentration only responded to HA application at the higher rate side.