Mitigating drought stress in fenugreek through synergistic effects of alanine and potassium-enriched biochar

Drought stress adversely affects plant growth, development, and yield. It can decrease seed germination, biomass accumulation, root proliferation, chlorophyll contents, and stomatal conductance. To overcome this critical issue, researchers suggest employing environmentally friendly approaches. The exogenous application of alanine (AL) acts as an osmolyte, which helps balance the cellular water under drought stress. It can also improve root architecture, biomass accumulation, and plant fertilizer use efficiency. Applying biochar can improve soil structure, water, and nutrient retention in soil, which are allied factors in enhancing plant growth under drought stress. Furthermore, the enrichment of potassium (K) in biochar also increases its availability to plants, directly regulating the stomatal conductance to alleviate drought stress. That's why the current study aims to explore the combined effect of AL and potassium-enriched biochar (KBC) on fenugreek cultivated under drought stress. Four levels of AL (control, 2mM, 4mM, and 6mM) were applied with 0%, 1%, and 2% KBC in three replicates. Results showed that 2mM AL + 2%KBC showed significant improvement in plant length (5.24%), plant fresh weight (25.36%), plant dry weight (16.23%), chlorophyll a (7.80%), chlorophyll b (15.83%), total chlorophyll (10.65%) over the control under drought stress. A significant increase in shoot N, P, and K concentration compared to control under drought stress also validated the effectiveness of 2mM AL + 2%KBC. In conclusion, 2mM AL + 2%KBC is an effective amendment for alleviating drought stress in fenugreeks. Under drought stress, growers are recommended to apply 2mM AL + 2%KBC to achieve better fenugreek growth.