<UnorderedList Mark="Bullet"> <ItemContent> Using 12-year water-nitrogen management soils, the MNC accumulation was investigated. </ItemContent> <ItemContent> Contributions of FNC and BNC to SOC show divergent responses to water-nitrogen practices. </ItemContent> <ItemContent> Reduced water-nitrogen input enhances MNC/SOC, primarily driven by FNC. </ItemContent> <ItemContent> Reduced water-nitrogen practices benefit SOC persistence and the GVP’s sustainability. </ItemContent> </UnorderedList>Soil microbial necromass carbon (MNC) plays a crucial role in the persistent soil organic carbon (SOC) pool. However, the impact of long-term different water-nitrogen managements on the soil MNC in the greenhouse vegetable production (GVP) remains unclear. Using a 12-year field experiment, coupled with soil physicochemical properties, C- and nitrogen (N)-related enzymatic kinetics and microbial communities’ measurements, the impact of six different water-nitrogen managements on MNC accumulation was examined. Our study showed that MNC constituted 47.7%–71.3% of SOC, with fungal necromass carbon (FNC) contributing 4.2-fold more than bacterial necromass carbon (BNC) on average. Compared to the high irrigation and chemical nitrogen fertilizer practices, water-saving practices under the high fertilization scenario increased BNC/SOC by 18.6% after the 12-year field manipulation. The reduced water-N treatments had the highest MNC/SOC proportions with an average of >60%, which was mainly attributed to the increased FNC/SOC. The relative importance partitioning results showed that root biomass, N-acetylglucosaminidase and C-cellobiohydrolase enzyme kinetics were the most important regulators of FNC/SOC, BNC/SOC and MNC/SOC, respectively. The partial least squares path modeling further revealed that soil substrates (e.g., root biomass and dissolved organic carbon) directly promoted FNC/SOC while suppressing BNC/SOC, whereas microbial communities enhanced both fractions. Hence, our study highlights the divergent response of FNC and BNC to the long-term water-nitrogen management in GVP. Therefore, optimized water-nitrogen management sustains crop productivity while enhancing MNC accumulation, thereby promoting SOC persistence and advancing green sustainable development of GVP.

Reduced water and nitrogen inputs boost microbial necromass carbon contributions to greenhouse soil organic carbon

期刊论文
发表日期：

2026年2月18日

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Zhou Jia,
Jianshuo Shi,
Chengzhang Wang,
Longgang Jiang,
Meng Li,
Ruonan Li,
Li Guo,
Yihong Li,
Liying Wang,
Erxiong Zhu

摘要

Using 12-year water-nitrogen management soils, the MNC accumulation was investigated.

Contributions of FNC and BNC to SOC show divergent responses to water-nitrogen practices.

Reduced water-nitrogen input enhances MNC/SOC, primarily driven by FNC.

Reduced water-nitrogen practices benefit SOC persistence and the GVP’s sustainability.

Soil microbial necromass carbon (MNC) plays a crucial role in the persistent soil organic carbon (SOC) pool. However, the impact of long-term different water-nitrogen managements on the soil MNC in the greenhouse vegetable production (GVP) remains unclear. Using a 12-year field experiment, coupled with soil physicochemical properties, C- and nitrogen (N)-related enzymatic kinetics and microbial communities’ measurements, the impact of six different water-nitrogen managements on MNC accumulation was examined. Our study showed that MNC constituted 47.7%–71.3% of SOC, with fungal necromass carbon (FNC) contributing 4.2-fold more than bacterial necromass carbon (BNC) on average. Compared to the high irrigation and chemical nitrogen fertilizer practices, water-saving practices under the high fertilization scenario increased BNC/SOC by 18.6% after the 12-year field manipulation. The reduced water-N treatments had the highest MNC/SOC proportions with an average of >60%, which was mainly attributed to the increased FNC/SOC. The relative importance partitioning results showed that root biomass, N-acetylglucosaminidase and C-cellobiohydrolase enzyme kinetics were the most important regulators of FNC/SOC, BNC/SOC and MNC/SOC, respectively. The partial least squares path modeling further revealed that soil substrates (e.g., root biomass and dissolved organic carbon) directly promoted FNC/SOC while suppressing BNC/SOC, whereas microbial communities enhanced both fractions. Hence, our study highlights the divergent response of FNC and BNC to the long-term water-nitrogen management in GVP. Therefore, optimized water-nitrogen management sustains crop productivity while enhancing MNC accumulation, thereby promoting SOC persistence and advancing green sustainable development of GVP.