滨海地区盐渍土改良对土壤有机碳固持的影响机理

Salt-affected soils as a main constraint factor have been effecting land sources development in china’s coastal areas. Salt-affected soils improvements have been an important primary work for land sources development, promoting soil quality, and conducting agro-forest cultivation. Soil improvement measures can significantly alter soil physico-chemical properties, influence on soil organic carbon fractions and its turnover, and further affect the capacity of soil organic carbon sequestration in coastal areas which are an important carbon pool. In this study, the research of effect of organic fertilizer, biomass carbon, humic acid and gypsum addition on the main influencing factors of soil organic carbon sequestration including soil physico-chemical properties, microbial community structure and soil organic carbon fractions and its turnover under three levels (low, medium, high) with a reference of conventional tillage by using experimental plot in Rudong coastal reclamation zone, Jiangsu Province. Finally, reveal the influencing mechanism of salt-affected soil improvements on soil organic carbon sequestration. This study has important significance to study on soil organic carbon evolution mechanism with human involvement, improve coastal soil organic sequestration strategy, make soil quality improvement plan, and guide future reserve land sources development.

盐渍土一直是影响我国滨海地区土地资源开发与利用的主要障碍。盐渍土的改良已经成为滨海地区进行土地资源开发、提升土壤质量、开展农林生产的重要前提。滨海盐渍土作为重要的碳汇，改良措施的实施会显著改变其土壤理化环境，影响土壤有机碳的组分与更新，进而影响滨海地区有机碳的固持。本研究拟借助野外试验田控制性试验，以江苏省如东县滩涂垦区为例，将传统耕作作为参照，研究有机肥、生物质炭、腐殖酸和石膏添加四种改良措施，在低、中、高三种水平下，分析土壤有机碳演变的关键影响因素的变化规律、阐明有机碳组分及其周转变化的影响机制，揭示不同盐渍土改良措施下土壤有机碳固持的主导机制及其影响机理。该项目对于研究人类活动参与下的滨海盐渍土有机碳库演化机理、优化土壤固碳策略、制定合理的盐渍土土壤质量提升方案、指导未来障碍性后备土地资源开发具有重要意义。

盐渍土一直是影响我国滨海地区土地资源开发与利用的主要障碍。同时滨海盐渍土也是滨海地区重要的碳库，滨海盐渍土的改良既可以提升区域的土壤质量，也能提升区域粮食安全的保障能力。本研究通过野外试验田控制性实验，以江苏省如东县豫东垦区作为试验区，通过定量添加石膏、有机肥、腐殖酸和生物质炭外源改良物质，并以玉米种植为主要作为作物类型，研究不同改良措施下土壤有机碳库主要影响因素的变化趋势，分析不同有机碳租库、微生物、碳同位素等有机碳库变化重要分量的演化规律，进而借助统计模型分析三大机制（物理、化学和生物）在盐渍土改良过程中对土壤有机碳库固持能力的影响机理。研究结果表明：滨海盐渍土添加腐殖酸和生物质炭对于土壤质量的提升具有非常明显的作用。而从长期改良的角度来看，添加500 kg/hm2腐殖酸或者生物质炭已经能够达到稳定改善土壤质量的效果。本研究可以为未来滨海盐渍土改良提供科学的指导方案。