What question did this study set out to answer?

To evaluate the impact of biochar on crop yield, greenhouse gas emissions, and soil organic carbon in saline-alkali soils.

March 29, 2026Open Access

Synergistic effects of biochar on soil organic carbon, greenhouse gas mitigation, and maize productivity in saline-alkali environments

QQQian QiInner Mongolia Agricultural University HSHaibin ShiInner Mongolia Agricultural University JYJianwen YanInner Mongolia Agricultural University

Key Points

To evaluate the impact of biochar on crop yield, greenhouse gas emissions, and soil organic carbon in saline-alkali soils.
Conducted a two-season experiment on mildly and moderately saline soils.
Applied four rates of biochar (0, 10, 20, 40 t·ha -1).
Measured crop yield, greenhouse gas emissions, and soil organic carbon levels.
Performed Pearson’s correlation analysis and regression optimization modeling.
Total CO2 emissions in moderate salinity were 14.70%-26.99% lower than in mild salinity.
Biochar increased crop yield by 14.51%-30.65% and soil organic carbon storage by 218.51%-404.52%.
Biochar reduced greenhouse gas intensity by 20.75%-41.84% and net emissions by 205.83%-437.14%.
Optimal biochar rates identified as 26.67 t·ha -1 for mild and 30.82 t·ha -1 for moderate salinity.

Abstract

Background and aims Biochar is a widely recognized amendment for augmenting crop productivity and mitigating greenhouse gas (GHG) emissions, particularly in degraded soil. However, optimal biochar rate and their mechanisms remain uncertain across different salinity severities. Methods To address this knowledge gap, a two crop seasons experiment was conducted from 2022 to 2023 on mildly (S1) and moderately (S2) saline soils, employing four biochar application rates: 0, 10, 20, and 40 t·ha -1 . This study systematically evaluated the effects of biochar on crop yield, GHG emissions, and soil organic carbon. Results The results revealed significant disparities in GHG emissions and carbon sequestration capacity between the two soil salinity levels. Under identical treatments, total soil CO 2 emissions in S2 were 14.70%–26.99% lower than those in S1, whereas total soil N 2 O, CH 4 emissions were elevated by 37.94%–61.04% and 34.41%–94.74%, respectively. For every 0.5 g·kg -1 increase in soil salinity, the soil organic carbon storage (SOCS) declined by 6.09%. Biochar application substantially increased crop yield (↑14.51%-30.65%) and SOCS (↑218.51%-404.52%) while concurrently mitigating global warming potential (GWP, ↓10.08%-24.12%), greenhouse gas intensity (GHGI, ↓20.75%-41.84%), and net greenhouse gas emissions (NGHGE, ↓205.83%-437.14%) (P 0.01). Pearson’s correlation analysis demonstrated significant negative correlations between SOC/SOCS and GHG emission indicators as well as a strong relationship between crop yield and GHGI. Conclusion Regression optimization modeling identified the optimal biochar application rates as 26.67 t·ha -1 for S1 and 30.82 t·ha -1 for S2, which achieved the most favorable balance between agricultural productivity and environmental benefits. This study demonstrates that appropriate biochar application can significantly enhance the carbon sink function of saline-alkali farmlands, reduce climate risks, and provide a promising strategy for sustainable agriculture in marginal lands.

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