Pongamia pinnata L. Leaves Biochar Increased Growth and Pigments Syntheses in Pisum sativum L. Exposed to Nutritional Stress

Pea (Pisum sativum L.) leaf chlorophyll and pigments syntheses are retarded under nutritional stress. Biochar has the potential to regulate soil nutrient supplies and optimize plant nutrient uptakes. We examine the role of Pongamia pinnata L. waste leaf biochar (PLB) in improving vegetative growth and leaf chlorophyll and accessory pigments of pea exposed to nutritional stress. Three PLB application rates (0, 1, and 2%) crossed with half (HF), and full NPK fertilizer (FF) recommended doses were applied to sandy soil field-pots (arranged in a completely randomized design). There were significant or maximum increases in plant vegetative or physiological traits, including the fresh or dry, above- and below-ground biomass weights, and photosynthetic pigments (chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, and anthocyanin) in response to a 2%PLB + FF application (p = 0.002). Trait values also responded to 2%PLB + HF, which signified the nutrient regulatory character of PLB (p = 0.038). The PLB-driven reduction in nutritional stress resulted in diminished lycopene (antioxidant) content (p = 0.041). Therefore, we suggest that the soil application of 2%PLB + FF has the greatest impact on pea vegetative growth and leaf chlorophyll, carotenoids, anthocyanin, and lycopene contents in Pisum sativum L. Further research is recommended to investigate the relationship of PLB with soil nutrient availabilities and plant nutrient concentrations.