凋落物源有机酸及其地下生态效应

本项目是在国家自然科学基金（30170768）和国家博士后科学基金（20070420153）资助下完成的，属于林学、土壤学和生态学交叉领域。 建立了森林凋落物中低分子有机酸的毛细管气相色谱分析法。揭示了落叶松、红松、白桦、水曲柳及杂木林凋落物的有机酸和凋落物溶出的低分子有机酸种类和数量动态，以及溶出有机酸与土壤温度、湿度、pH 值等指标的关系。凋落物溶出的低分子有机酸主要有草酸、丁二酸、柠檬酸等。这些低分子有机酸可显著增加土壤磷素养分及金属元素的释放，释放的主要机理在于有机阴离子的金属络合作用，而非简单的酸溶解作用。根据凋落物溶出的有机酸数量和有机酸对土壤磷的释放效应，估算出有机酸对土壤磷的释放量是相当可观的，因而对林木磷营养有重要现实意义。 有机酸的不利方面是：其一，在促进磷等养分释放的同时，也能显著促进污染土壤中Pb、Cd 等重金属的释放 其二，较高浓度的低分子有机酸对林木根系发育有抑制作用。提出了以凋落物调控为基础的森林生态系统土壤养分活化途径。研究结果填补了我国森林土壤研究中的知识空白。 项目成果在用材林土壤养分活化和林木生理生态过程的外源调控、“有机酸缓释型土壤养分活化剂”的开发研制、荒山荒地造林中的树种选择和森林凋落物管理、矿区污染土壤造林树种选择和生态风险规避等领域均有良好应用前景。

This project was supported by the National Natural Science Foundation of China (30170768) and the China Postdoctoral Science Foundation (20070420153), and falls within the interdisciplinary field of forestry, pedology and ecology. A capillary gas chromatography analysis method for low-molecular-weight organic acids in forest litters was established. The dynamics of types and contents of organic acids in litters of larch, Korean pine, birch, Manchurian ash and mixed broad-leaved forest, as well as the low-molecular-weight organic acids leached from these litters, were clarified, along with the correlations between the leached organic acids and indicators such as soil temperature, moisture and pH value. The main low-molecular-weight organic acids leached from litters include oxalic acid, succinic acid, citric acid and others. These low-molecular-weight organic acids can significantly promote the release of soil phosphorus nutrients and metal elements, and the primary mechanism behind this release is the metal complexation of organic anions rather than simple acid dissolution. Based on the quantity of organic acids leached from litters and their effect on soil phosphorus release, it was estimated that the amount of soil phosphorus released by organic acids is considerable, thus holding important practical significance for the phosphorus nutrition of forest trees.

The adverse effects of organic acids are as follows: firstly, while promoting the release of nutrients such as phosphorus, they can also significantly enhance the release of heavy metals like Pb and Cd in contaminated soils; secondly, low-molecular-weight organic acids at high concentrations can inhibit the root development of forest trees. Pathways for soil nutrient activation in forest ecosystems based on litter manipulation were proposed. The findings of this study fill the knowledge gap in domestic forest soil research.

The project achievements have promising application prospects in multiple fields, including exogenous regulation of soil nutrient activation and physiological-ecological processes in timber forests, development and preparation of "slow-release organic acid soil nutrient activators", tree species selection and forest litter management during afforestation on barren hills and wastelands, as well as tree species selection for afforestation in mining-contaminated soils and ecological risk avoidance.

搜集汇总

背景与挑战

背景概述

该数据集研究了森林凋落物中低分子有机酸（如草酸、丁二酸、柠檬酸）的种类和数量动态，及其对土壤磷素养分和重金属释放的影响。研究揭示了有机酸通过金属络合作用促进养分释放的机理，并探讨了其在森林生态系统土壤养分活化和污染土壤治理中的应用前景。