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<p>Although some evidence has revealed the effects of nitrogen (N) management strategies on conventional soil organic carbon (SOC) fractions, knowledge gaps persist regarding other important SOC forms, particularly those derived from microbial sources. To elucidate the mechanisms through which N input levels influence the accumulation of SOC and it sub-pools as well as their association with crop yield, a field experiment was initiated in 2013 in a typical double-cropping rice system in China. To systematically assess their effects on both biological and non-biological SOC components, five N fertilizer input gradients (0/0, 105/126, 120/144, 135/162, and 150/180 kg N ha<sup>-1</sup> year<sup>-1</sup>) were established for both early and late rice seasons. Soil samples were collected and grain yield and plant biomass were measured during the maturity stages of both the rice seasons in 2023 and 2024. Soil microbial-derived C forms was quantified using amino sugar markers, and the abundances of 23 biomarker genes related to soil C fixation and degradation were measured via high-throughput quantitative PCR. The data from 2023 to 2024 indicated that, compared to the control, N inputs significantly increased soil total N and SOC contents by 5.6%-79.2% and 7.1%-42.8%, respectively. With increasing N inputs, soil total N and available N content exhibited a gradual upward trend, whereas the content of SOC and its major components first increased and then declined or tended to stabilize. Soil fungal and bacterial necromass C contributions to SOC decreased by 6.8%-21.0% and 3.8%-20.9% with increasing N inputs, respectively. Nitrogen input significantly enhanced the abundances of most C-fixation genes while reducing those of C-degradation genes in both rice seasons. Among all predictors, soil total amino sugar content exhibited the strongest prediction for SOC, followed by microbial biomass N and the contribution of microbial necromass C to SOC. Increases in N inputs significantly improved rice straw and grain yields, with yields showing a gradual increase followed by stabilization at higher N levels. The soil microbial biomass C and N, dissolved organic C content, the contribution of fungal necromass C to SOC, and the <i>acsE</i>, <i>aclB</i> and <i>rbcL</i> abundances were the main prediction of the grain yields.</p>

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Nitrogen fertilization simultaneously strengthens soil carbon and nitrogen pools, with implications for productivity gain of double-cropping rice system

  • 期刊论文

  • 发表日期：

    2026年1月2日

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  • Junru Li,
  • Yao Liu,
  • Hao Huang,
  • Ning Su,
  • Qiulong Hu,
  • Xiangmin Rong,
  • Yuping Zhang,
  • Jianwei Peng,
  • Gongwen Luo

摘要

Although some evidence has revealed the effects of nitrogen (N) management strategies on conventional soil organic carbon (SOC) fractions, knowledge gaps persist regarding other important SOC forms, particularly those derived from microbial sources. To elucidate the mechanisms through which N input levels influence the accumulation of SOC and it sub-pools as well as their association with crop yield, a field experiment was initiated in 2013 in a typical double-cropping rice system in China. To systematically assess their effects on both biological and non-biological SOC components, five N fertilizer input gradients (0/0, 105/126, 120/144, 135/162, and 150/180 kg N ha-1 year-1) were established for both early and late rice seasons. Soil samples were collected and grain yield and plant biomass were measured during the maturity stages of both the rice seasons in 2023 and 2024. Soil microbial-derived C forms was quantified using amino sugar markers, and the abundances of 23 biomarker genes related to soil C fixation and degradation were measured via high-throughput quantitative PCR. The data from 2023 to 2024 indicated that, compared to the control, N inputs significantly increased soil total N and SOC contents by 5.6%-79.2% and 7.1%-42.8%, respectively. With increasing N inputs, soil total N and available N content exhibited a gradual upward trend, whereas the content of SOC and its major components first increased and then declined or tended to stabilize. Soil fungal and bacterial necromass C contributions to SOC decreased by 6.8%-21.0% and 3.8%-20.9% with increasing N inputs, respectively. Nitrogen input significantly enhanced the abundances of most C-fixation genes while reducing those of C-degradation genes in both rice seasons. Among all predictors, soil total amino sugar content exhibited the strongest prediction for SOC, followed by microbial biomass N and the contribution of microbial necromass C to SOC. Increases in N inputs significantly improved rice straw and grain yields, with yields showing a gradual increase followed by stabilization at higher N levels. The soil microbial biomass C and N, dissolved organic C content, the contribution of fungal necromass C to SOC, and the acsE, aclB and rbcL abundances were the main prediction of the grain yields.