Optimizing the Application Timing of Liquid Organic Formulations and Their Effect on Sustainable Cowpea Production in Soils of Eastern Indian Plateau

Organic-based agricultural practices are gaining attention today in India because of their production and ecological sustainability emphasizing the use of different indigenous seed treatment (SDT) and soil treatment (SLT) formulations. However, the nutritional and microbiological characterization of the formulations, their temporal changes after different days of incubation, and their most effective day of application in crop production have been rarely addressed. The present study aims to investigate the decomposition rate of two SDT formulations (beejamrit, BJ; beej sanjeevani, BS) and six SLT formulations (enriched sanjeevani, ES; jeevamrit, J-Con; four low-cost J-Con alternatives, J-Alt1 to 4) for 12 consecutive days to note the optimal day of their application. Further, we assessed the effect of twelve SDT+SLT combinations on the performance of cowpea in a 13-year-old organic production system. On average, pH, organic carbon, and nutrient contents undergo a gradual depletion with incubation. The bacterial and fungal populations gradually increased with incubation, and reaching their maximum (5–7 and 2–3 days, respectively) got decreased. The most appropriate time for SDT and SLT application was 4th–5th and 6th–7th day, respectively, after fermentation. In the case of field experiment, BJ-(J-Con) was the most suitable SDT+SLT treatment combination for growing cowpea organically experiencing different growth, yield, agro-meteorological, and economical parameters. BS-(J-Con) showed similarities to BJ-(J-Con) where the principal component analysis identified the most crucial crop parameters. The investigation highlights the scientific insights of different SDT and SLT formulations for their effective use in organic crop production.