江汉平原“一种两收”种植模式下多年生稻对土壤团聚体稳定性和有机碳的短期影响*

The short-term effects of perennial rice on soil aggregate stability and organic carbon under the "one crop, two harvests" cropping system in Jianghan Plain

    摘要
  • 摘要: 探讨短期不同种植模式下多年生稻对土壤团聚体稳定性和有机碳（SOC）的影响，为优化江汉平原地区农田耕作管理措施，实现土壤固碳减排提供理论依据。采用裂区试验设计，主区为2种“一种两收”种植模式（常规和刈割再生模式），裂区为4个水稻品种（多年生稻品种PR25和PR109，本地常规品种FLY和YXY）。利用干筛法分离测定表层（0-20 cm）和亚表层（20-40 cm）土壤大（2 mm）、较大（0.25-2 mm）、微（0.053-0.25 mm）和粉黏（0.053 mm）团聚体组分及其SOC，并分析团聚体稳定、年均地下碳投入量和SOC的关系。结果表明，与本地水稻品种相比，多年生稻PR109显著提升刈割模式下表层和亚表层土壤SOC含量、大团聚体组分及其SOC含量和团聚体稳定性，同时降低土壤可蚀性因子K值。而在常规模式下，PR109仅对亚表层土各指标有提升效果。进一步分析，PR25和PR109均显著提高地下碳的输入，且亚表层土SOC含量与地下碳输入之间存在显著的线性相关性（P<0.01），说明地下碳输入的增加有助于土壤SOC的积累。此外，土壤团聚体稳定性和可蚀性因子K值与团聚体粒径分布呈显著相关，表明大团聚体在提高土壤抗侵蚀能力方面起到关键作用。综上，适宜的多年生稻品种（PR109）能显著提升土壤团聚体稳定性和有机碳，同时结合刈割模式能进一步提升水土保持和固碳效益。

     

    Abstract: To investigate the effects of different short-term cropping systems on soil aggregate stability and soil organic carbon (SOC) in perennial rice, aiming to provide theoretical support for optimizing tillage management practices in farmland across the Jianghan Plain region and achieving soil carbon sequestration and emission reduction. A split-plot design was employed, with the main plots comprising two ‘one-crop-two-harvest’ cropping systems (conventional and mowing system) and the split plots consisting of four rice varieties (perennial rice varieties PR25 and PR109, and local conventional varieties FLY and YXY). Dry sieve analysis separated and measured macro (2 mm), meso (0.25–2 mm), micro (0.053–0.25 mm), and silt-clay (0.053 mm) aggregate fractions and their SOC in the topsoil (0–20 cm) and subsoil (20–40 cm). Relationships among aggregate stability, annual average subsurface carbon input, and organic carbon were analyzed. Compared with local rice varieties, perennial rice PR109 under significantly increased both topsoil and subsoil SOC content, large aggregate fraction, aggregate SOC content, and aggregate stability under mowing system, while reducing soil erodibility factor K. PR109 only enhanced indicators of subsoil under the mowing regime. Further analysis revealed that both PR25 and PR109 significantly increased belowground carbon inputs. Linear regression analysis demonstrated a significant linear correlation (P<0.01) between subsoil SOC content and belowground carbon inputs, indicating that increased belowground carbon inputs contribute to soil SOC accumulation. Moreover, soil aggregate stability and the erosion susceptibility factor K value showed significant correlations with aggregate size distribution, indicating that larger aggregates play a crucial role in enhancing soil erosion resistance. In summary, suitable perennial rice varieties (PR109) can significantly enhance soil aggregate stability and organic carbon content. When combined with a mowing management system, they further improve soil and water conservation and carbon sequestration benefits.

     

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