Evaluating the Effect of Organic Manure and Agricultural Lime on Chlorophyll and Oxidative Stress Enzymes of Dry Bean (Phaseolus vulgaris) and Moth Bean (Vigna aconitifolia)

Background: Chlorophyll content in green plant is an important pigment that supports food manufacturing during the process of photosynthesis and enzymes are antioxidant system in plants that fight against oxidative stress generated by reactive oxygen species (ROS).

Aim: This study was designed to evaluate the effect of organic manure and agricultural lime on the chlorophyll and oxidative stress enzymes of two bean varieties.

Methodology: The three locations were: Akamkpa with pH 4.0, Calabar Municipality with pH 7.0 and Odukpani with pH of 9.0. The treatments were; control (0 g), OM1 (100 g organic manure), OM2 (200 g organic manure), AL1 (100 g agricultural lime), AL2 (200 g agricultural lime), OM1 + AL1 (50 g organic manure + 50 g agricultural lime) and OM2 +AL2 (100 g organic manure and 100 g agricultural lime.

Results: Chlorophyll a was highest in AL2 (154.21 µg/gFW) of P. vulgaris. Chlorophyll b was highest in OM1 + AL1 (176.00 µg/gFW) grown in Akamkpa soil (P<0.05). In Akamkpa soil, OM1 + AL1 and OM2 of V. aconitifolia had higher chl. b and total chl. (a + b) content than the control with mean values of 152.33 µg/gFW for OM1 + AL1 and 298.67 µg/gFW for OM2. In Akamkpa soil, peroxidase activity was high in OM1 (888.62 µmol/product/L/min) of P. vulgaris which was statistically higher than the control with mean value of (535.36 µmol/product/L/min). POD activity in V. aconitifolia, grown on Akamkpa soil treated with OM1, OM1 + AL1 and OM2 had significantly (P<0.05) higher mean values of (717.64, 708.39 and 694.27 when compared with the untreated soil (566.14d±17.53 µmol/product/L/min). P. vulgaris grown on Odukpani treated with OM1 + AL1 and OM2 + AL2 had the highest PPO activity of 0.77 µmol/product/L/min. PPO activity of V. aconitifolia grown on Odukpani treated with of OM1 + AL1 revealed highest activity (0.78 µmol/product/L/min) compared to control (0.39 µmol/product/L/min).

Conclusion: From the findings of this study, organic manure and agricultural lime are two fertilizer sources recommended for incorporation into agronomic practices for enhanced plant performance.