Biochar effects on greenhouse gas emissions from a furrow‐irrigated cotton–corn rotation on silt‐loam soil in southeast Arkansas

Abstract

As a conservation agricultural practice, biochar application may have a role in potentially reducing agroecosystem climate impacts. The objective of this field study was to quantify the impacts of biochar rate (i.e., 0, 2000, and 4000 kg ha ⁻¹ ), applied for three consecutive years, on carbon dioxide (CO ₂ ), methane (CH ₄ ), and nitrous oxide (N ₂ O) emissions and global warming potential (GWP) from a 2‐year, furrow‐irrigated cotton ( Gossypium hirsutum ) and corn ( Zea mays ) rotation on a silt‐loam soil (Aeric Epiaqualfs) in southeast Arkansas. Among biochar rates, no differences in season‐long greenhouse gas (GHG) emissions were reported in either growing season, but, averaged over time, 2024 CO ₂ fluxes were 649 and 637 mg m ⁻² h ⁻¹ from the 2000 and 4000 kg ha ⁻¹ biochar rates, which did not differ, and were greater ( p  < 0.01) than the 0 kg ha ⁻¹ biochar rate (558 mg m ⁻² h ⁻¹ ). Nitrous oxide fluxes in 2025 were greatest ( p  < 0.05) from the 4000 kg ha ⁻¹ treatment (0.12 mg m ⁻² h ⁻¹ ), lowest from the 2000 kg ha ⁻¹ treatment (0.07 mg m ⁻² h ⁻¹ ), while the control (0.09 mg m ⁻² h ⁻¹ ) did not differ from both biochar rates. Season‐long GHG emissions did not significantly differ by biochar rate in either growing season. Annual and 2‐year cumulative gas emissions and GWP from the cotton–corn rotation did not differ ( p  > 0.05) among biochar rates. Results of this study highlight biochar's potential to reduce N ₂ O fluxes from silt‐loam‐textured, upland, row‐crop agroecosystems over 2 years.