可溶性有机物对红壤复合体形成的影响及其机制

Red soil is one of the soils with the most important and biggest productive potential in southern China, and it plays a very important role in increasing the production efficiency and sustainable agriculture development. It is difficult to improve the quality of red soil because its characteristics of acidity, higher clay content, compaction nature and low productivity. The objective of the project is to increase the content of organic-mineral complex, which is the key factor of the fertility, by applying dissolved organic matter (DOM). The latter is the important intermediate during organic matter mineralization and humification as well as the active part of organic matter. In this project, through the incubation experiments and field simulation tests, the effect of DOM from livestock manure, plant, or humus on the formation of the organic-mineral complexes in soils derived from different parent materials including quaternary red clay, purple sandy shale, limestone, plate shale, and granite will be studied. The relationship models will be set up. Near infrared spectroscopy and synchrotron radiation techniques will be employed to explore the interaction mechanisms between the complexes and DOM. Furthermore, soil moisture or temperature change influencing the formation of DOM-soil clay complexes will be elucidated. Observations will indicate the restrictive factors of organic-mineral complex formation in red soil, uncover the mechanism of complex formation and stability, and provide theoretical support for improving soil fertility and productivity of red soil.

红壤是南方地区最重要、也是面积和生产潜力很大的一类土壤，在区域农业增产增效和可持续发展中占有十分重要的位置。本项目基于红壤“酸粘板瘦”的特点和生产力低下、改良难度大的事实，从提升其肥力的关键因子——有机无机复合体的含量入手，以有机物矿化和腐殖化进程中的重要中间产物、也是有机质中最活跃组分的可溶性有机物为材料，通过室内培养、野外模拟培养等方法，研究畜禽粪便、植物源、腐殖质等来源可溶性有机物对第四纪红土、花岗岩、板页岩、石灰岩及紫色沙页岩等母质发育红壤复合体形成的影响，并试图建立相互间的关系模型；利用近红外光谱、同步辐射等检测手段，探讨其相互复合的机制；同时，研究土壤水分、温度等要素对可溶性有机物与红壤粘粒复合及对复合体形成等的影响，阐释其相互间的关联。通过项目研究，明确影响红壤有机无机复合体形成的制约因子，探讨复合体形成与稳定的机制，为提高红壤肥力和生产力提供理论支撑。

红壤是南方地区最重要、也是面积和生产潜力很大的土壤，在区域农业增产增效和可持续发展中占有十分重要的位置。本项目基于红壤旱地“酸粘板瘦”特点和生产力低下、改良难度大的事实，从剖析红壤肥力的关键因子——有机无机复合体的含量和性质入手，以有机物矿化和腐殖化进程中的重要中间产物、也是有机质中最活跃组分的可溶性有机物为材料，通过长期定位试验、室内培养及原位培养等方法，研究不同来源可溶性有机物对第四纪红土母质发育红壤有机无机复合特征及碳氮空间分布的影响；利用红外光谱、13C核磁共振、X射线衍射及X射线光电子能谱等检测手段，探讨了可溶性有机物与红壤黏土矿物相互复合的机制；同时，研究了土壤水、肥等要素对可溶性有机物与红壤粘粒复合及对复合体形成等的影响，揭示了其相互间的关联机理。通过项目研究，发表研究论文10篇，培养硕士和博士研究生7人，发现了腐殖质形态和铁铝矿物类型影响红壤有机无机复合的过程，阐明了外源有机物施入量及种类对腐殖质组分和铁铝矿物形态的影响，阐释了外源可溶性有机物对红壤有机无机复合特征的作用机理，并明确了影响红壤有机无机复合体形成的制约因子，揭示了复合体形成与稳定的机制，为提高红壤肥力和生产力提供了理论支撑。