Biostimulant-mediated enhancement of productivity and quality of Indian mustard under contrasting agro-climatic environments in India

Achieving food and nutritional security under the growing pressures of climate change is a critical challenge for oilseed-based farming systems in India, where Indian mustard ( Brassica juncea L.) is a major source of edible oil and dietary protein. Mustard productivity across diverse agro-climatic regions is frequently constrained by nutrient-use inefficiency, erratic rainfall, and temperature extremes, while sole dependence on conventional fertilizers has shown limited effectiveness in sustaining yield and quality. To address these challenges, a multi-location field experiment was conducted under contrasting agro-ecological conditions in semi-arid Jhansi (Uttar Pradesh) and humid subtropical Ranchi (Jharkhand) to evaluate the efficacy of biostimulants on crop productivity, nutrient dynamics, and stress resilience. Five biostimulant formulations botanical extract, humic acid + fulvic acid (powder, liquid, and granules), and protein hydrolysate + amino acid applied at four recommended doses in a factorial randomized block design with four replications. Biostimulant application significantly improved crop growth, biomass accumulation, and productivity across both locations, with seed yield increases ranging from 9.6 to 30.6% and stover yield improvements of 6.6 to 28% over the control. Quality parameters also improved substantially, with protein content increasing by 7–17% and oil yield by 7.5–27.7%. The botanical extract applied at the higher dose consistently recorded the highest seed yield (up to 2.31 t ha -1 ) and oil yield (up to 0.86 t ha -1 ), particularly under humid subtropical conditions at Ranchi. Multivariate analysis revealed strong positive associations among seed yield, oil yield, and biomass-related traits, with clear location-specific clustering of responses, indicating pronounced environment-dependent effectiveness of biostimulants. Overall, the findings demonstrate that targeted biostimulant application, especially botanical extracts, can enhance productivity, quality, and climate resilience of mustard across contrasting environments, offering a sustainable and resource-efficient strategy to strengthen food and nutritional security while reducing reliance on chemical fertilizers under changing climatic conditions. • Biostimulants increased mustard seed yield by 9.6–30.6% across locations • Oil yield improved by 7.5–27.7%, driven mainly by higher seed productivity • Botanical extract produced the highest seed yield (up to 2.31 t ha -1 ) • Seed protein content increased by 7–17% with biostimulant application • Strong location × biostimulant × dose interactions revealed climate sensitivity