Optimizing soil health through activated acacia biochar under varying irrigation regimes and cultivars for sustainable wheat cultivation.

Wheat, a staple food crop globally, faces the challenges of limited water resources and sustainable soil management practices. The pivotal elements of the current study include the integration of activated acacia biochar (AAB) in wheat cultivation under varying irrigation regimes (IR). A field trial was conducted in the Botanical Garden, University of the Punjab, Lahore during 2023-2024, designed as a split-split-plot arrangement with RCBD comprising three AAB levels (0T, 5T, and 10T, T = tons per hectare) three wheat cultivars (Dilkash-2020, Akbar-2019, and FSD-08) receiving five IR levels (100%, 80%, 70%, 60%, and 50% field capacity). Biochar amended soil showed improved BET surface area, pore size, and volume. Carbon recovery (45%) and carbon sequestration capacity (49%) of 10T-AAB amended soil were better than non-amended soil (0.43% and 0.13%, respectively). The 10T-AAB amendment significantly improved the soil's microporosity and water retention capacity, increasing it by 1.1 and 2.2 times, respectively. Statistical analysis showed that a reduction in IR negatively affected plant growth and yield. The 10T-AAB levels significantly increased sugar contents (14%), relative water content (10-28%), membrane stability index (27-55%), and photosynthetic pigments (18-26%) of wheat leaves under deficit irrigation among all the cultivars. Maximum stress markers (catalase, proline, peroxidase, and superoxide dismutase) were observed from Akbar under 50% irrigation with 0T-AAB, and the least were observed from 50% irrigated Dilkash-2020 with 10T-AAB amended soil. Among cultivars, Dilkash-2020 was observed to be the best for maximum yield, followed by FSD-08 and Akbar-2019, respectively. When compared to other IR levels, 10T-AAB amended soil had the highest yield enhancement (12, 11, and 9.2 times for Dilkash-2020, FSD-08, and Akbar-2019, respectively). Hence, AAB enhanced wheat production by improving soil properties, drought resilience, and yield attributes.