Morpho-physiological characteristics of Vigna unguiculata [L.] Walp grown in a controlled environment using effluents from a beverage bottling company

The use of industrial effluents for agricultural practices due to waste management properties, water scarcity, or cultural belief affects both the physiology and morphology of cultivated crops. This study reports the investigation of the agro-potentiality of the effluents from a beverage bottling company on cowpea (Vigna unguiculata) under a controlled environment. This greenhouse experiment was carried out within Obafemi Awolowo University. The effluents were applied at 0, 10, 20, 30, 40, and 50% concentrations using untreated (A) and treated (B) effluents separately in two groups. Physicochemical properties of the effluents were determined using standard methods. Exchangeable cations present in the effluents were investigated via the ammonium acetate exchange way. Morphological and yield parameters were measured in ten replicates. Transverse sections of the leaf, petiole, and stem were also investigated under a light microscopy. General linear model was used for statistical analysis with means compared using Tukey’s HSD test at p < 0.05. The effluents had pH, electrical conductivity, and total dissolved solids in the range of 7.4–7.5, 599.0–693.0 μS/cm, and 395.0–455.0 mg/l, respectively. The exchangeable calcium and potassium concentrations in the effluents range 1067.00–1937.50 and 190.0–343.50 mg/l. Application of effluent A had no significant effect on number of pods per group, seeds per pod, leaf length, leaf width, and leaf area of cowpea (p > 0.05). There was a significant effect of effluent A on the number of leaves and shoot height (p < 0.05). The application of effluent B had a significant effect on the mean number of leaves and seeds per pod at higher (40–50%) concentrations (p < 0.05). Amendment with effluent B showed no significant effect on the mean shoot height, leaf length, width and area, pods per group, pod length, and girth size (p > 0.05). The frequency of guard cells was observed to decrease with increasing effluents (A and B) concentration on the abaxial epidermis. Likewise, a “black deposit” was observed in the vessels in the stem taken from group amended with effluent A at high concentrations (30–50%). No anatomical differences were observed in the petiole and leaf transverse sections of the control and amended subgroups. The untreated and treated effluents showed agro-potentiality. However, crops grown need to be monitored for the health impacts on man and animal, as risk of crop cellular disruption exist.