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Background and aims <p>The impact of straw incorporation on the transformation and stability of soil organic carbon (SOC) has not been fully understood with the changes in cropping systems. To address this issue, we investigated how return of straw from different preceding crops of rice-based double cropping affects retention and allocation of straw-C and intrinsic SOC across SOC fractions in paddy soil.</p> Methods <p>An 816-day field incubation of <sup>13</sup>C-enriched maize straw from maize-late rice cropping (MR-SM) and early rice straw from double rice cropping (RR-ER) were conducted in the respective rice-based cropping plots.</p> Results <p>Compared to RR-ER incubation, MR-SM treatment demonstrated a significantly lower retention percentage of straw-C and intrinsic SOC by the conclusion of 816&#xa0;days, had a lower sequestration rate of straw-derived C and a higher loss rate of the intrinsic SOC over this period, resulting in 5.49% reduction in TOC than that of RR-ER treatment. Meanwhile, MR-SM treatment showed significantly higher contributions of straw-C in the intra-microaggregate particulate fraction (iPOC) and the mineral-associated fraction (MAOC), but it contributed lower straw-C to the microbial biomass carbon (MBC). In contrast to RR-ER treatment, MR-SM treatment partitioned more SOC within iPOC but less SOC in MAOC, thus it had a higher index of the carbon quality, indicating a decline in SOC stability in the MR cropping despite a notable increase in TOC over the incubation period.</p> Conclusion <p>The maize-rice double cropping presents a lower potential for sequestration of newly added straw-C and the maintenance of SOC stability compared to RR cropping.</p>

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Incorporation of straw from maize and early rice differentiated sequestration and stability of soil organic carbon–A long-term field incubation of 13C-labelled straw under maize -rice and double rice cropping

  • 期刊论文

  • 发表日期：

    2025年6月5日

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  • Ming Zhan,
  • Mingguang Qin,
  • Xuedong Fang,
  • Moussa Traore,
  • Yingjian Cao,
  • Chengfang Li

摘要

Background and aims

The impact of straw incorporation on the transformation and stability of soil organic carbon (SOC) has not been fully understood with the changes in cropping systems. To address this issue, we investigated how return of straw from different preceding crops of rice-based double cropping affects retention and allocation of straw-C and intrinsic SOC across SOC fractions in paddy soil.

Methods

An 816-day field incubation of 13C-enriched maize straw from maize-late rice cropping (MR-SM) and early rice straw from double rice cropping (RR-ER) were conducted in the respective rice-based cropping plots.

Results

Compared to RR-ER incubation, MR-SM treatment demonstrated a significantly lower retention percentage of straw-C and intrinsic SOC by the conclusion of 816 days, had a lower sequestration rate of straw-derived C and a higher loss rate of the intrinsic SOC over this period, resulting in 5.49% reduction in TOC than that of RR-ER treatment. Meanwhile, MR-SM treatment showed significantly higher contributions of straw-C in the intra-microaggregate particulate fraction (iPOC) and the mineral-associated fraction (MAOC), but it contributed lower straw-C to the microbial biomass carbon (MBC). In contrast to RR-ER treatment, MR-SM treatment partitioned more SOC within iPOC but less SOC in MAOC, thus it had a higher index of the carbon quality, indicating a decline in SOC stability in the MR cropping despite a notable increase in TOC over the incubation period.

Conclusion

The maize-rice double cropping presents a lower potential for sequestration of newly added straw-C and the maintenance of SOC stability compared to RR cropping.