Synergistic Application of Biochar, Arbuscular Mycorrhizal Fungi, and Optimized Fertilization for Sustainable Sunflower Production in Semi-Arid Environments

Author(s)
Safahani, Alireza
Mohseni, Behrooz
Date Issued
2026
Type
article
DOI
Journal
Abstract
Sustainable intensification of sunflower (Helianthus annuus L.) cultivation is essential for maintaining productivity under increasing environmental constraints and for reducing the carbon footprint of agriculture. This study evaluated the combined effects of biochar, arbuscular mycorrhizal fungi (AMF), and fertilization strategies on sunflower yield and greenhouse gas (GHG) emissions in a semi-arid Mediterranean environment. Field experiments were conducted during the 2020 and 2021 growing seasons in Golestan Province, Iran, using a randomized complete block design with three replications. Treatments included three biochar rates [0 (B0), 3 (B3), and 6 (B6) t ha⁻¹], AMF inoculation (AM⁺ vs. AM⁻), and three fertilization levels, expressed as a percentage of the Recommended Fertilization (RF) rate [100% (RF100), 75% (RF75), and 50% (RF50)]. Crop performance, nutrient use efficiency, and soil emissions of CO₂, N₂O, and CH₄ were measured throughout the growing cycle. Biochar increased sunflower yield by up to 44% (B6 relative to the B0 control), while AMF inoculation improved yield by 9% (relative to the AM⁻ control). N₂O emissions decreased by 29% and 54% under RF75 and RF50, respectively, compared with RF100. The combination RF75–B6–AM⁺ produced the highest yield and the lowest greenhouse gas emission intensity (GHGI), reducing it by 40% relative to RF100. CO₂ fluxes were temperature-dependent and enhanced by biochar and AMF through increased microbial and root respiration, whereas CH₄ fluxes remained low across treatments. Integrating biochar, AMF, and moderate fertilization (RF75–B6–AM⁺) sustains sunflower productivity while mitigating GHG emissions, offering a viable low-input, climate-smart strategy for semi-arid cropping systems. © The Author(s) under exclusive licence to Sociedad Chilena de la Ciencia del Suelo 2026.
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