Moisture Retention Effectiveness of a Biochar and Coir Mixture on Soybean: Evaluation through Physiological and Yield Indicators

This study investigates the moisture retention effectiveness of a biochar and coir mixture on soybean (Glycine max L.) under drought stress by evaluating key physiological and yield indicators. Experimental assessments included chlorophyll fluorescence efficiency, SPAD index, ion leakage, and vapor saturation deficit before, during, and after controlled drought and rehydration periods. Yield performance was measured in terms of individual plant yield, theoretical yield, and actual yield under both drought-treated (B) and non-drought-treated (A) conditions. Results indicate that while physiological indicators declined during drought, the biochar and coir mixture reduced yield losses to a modest 6-9%. This limited reduction in yield under drought suggests that the biochar and coir mixture provided partial moisture retention, aiding in the recovery of physiological stability and yield following rehydration. Thus, this study affirms the role of biochar and coir as an effective moisture-retaining solution, supporting soybean productivity under water-limited conditions.