Soil remediation modulates Cd content and CH4 emission in a karst rice paddy

Abstract

Abstract Rice (Oryza sativa L.) paddies are increasingly threatened by cadmium (Cd) pollution, and potentially serve as methane (CH4) emitters to the atmosphere. Remediation agents widely mitigate Cd pollution in paddy soil, however, we know little about their regulations on CH4 emission. Here, via adding biochar (B), sulfhydryl-modified palygorskite (SMP), and selenium foliar fertilizer (SFF), we conducted a pot experiment to investigate soil and rice Cd changes together with in-situ CH4 fluxes. We suggest that SMP, SFF, and mixed B-SMP significantly facilitate Cd remediation. CH4 outgassing increased gradually along the growing season, with the cumulative CH4 fluxes ranging between 338.82 and 619.13 kg∙hm− 2. Agents 7% B, 7% B-0.01% SMP and SFF reduced CH4 emissions by 8.46%, 5.30%, and 4.11%, respectively. Our results highlight that mixed 7% B-0.01% SMP and SFF showed collaborative effects on Cd remediation and CH4 emission. This study reveals the feasibility of reducing Cd pollution and CH4 evasion in a karst rice paddy, which hopes to supplement knowledge of collaborative controls on soil remediation and carbon emission.