Organic Material Based Seed Coating To Improve Rhizosphere Activity and Productivity of Blackgram (Vigna mungo (L))

The use of polymer-based inorganic seed coatings pollutes the soil by introducing microplastics, disrupting plant and microbial synergy, reducing soil organic carbon content, and affecting crop productivity over prolonged use. To mitigate this problem, this study aimed to develop an organic seed coating formulation (OSF) and evaluate its effects on rhizosphere microbial populations and blackgram seed performance under field conditions. The OSF, containing various nutrients derived from biodegradable waste materials such as groundnut shell (biochar), Crab shell (chitosan), bone meal (biochar and gelatin), fish scales (biochar and collagen), glycerol (a byproduct of the biodiesel industry), and gum acacia, was formulated. The prepared OSF was characterized and tested for its effects on blackgram seed germination, root development, plant-microbe synergy, and seed yield. Blackgram seeds coated with OSF (8 g/kg) exhibited enhanced germination under both in vitro (84.0%) and in vivo (94.0%) conditions. Treated seeds showed advanced xylem and phloem differentiation, development of strong root systems with larger surface areas (18.61 cm²) and diameters (0.624 mm), along with the highest root dehydrogenase activity. Seedlings from coated seeds formed well-defined nodules along the root length, enhancing nutrient absorption. Consequently, seeds coated with OSF at 8 g/kg of seeds resulted in higher seed yields under field conditions compared to untreated plants. Blackgram seeds coated with organic seed coating formulation at 8 g/kg of seed not only facilitates seed germination but also serves as a catalyst for enhancing soil microbial communities, thereby fostering sustainable agricultural practices, increasing root morphology, and ensuring higher yields in blackgram cultivation.