蚯蚓活动对赤红壤水分运动影响与机制研究

The heavy texture, as well as the "harden in dry season, but muddy in moist season" water characteristics of the lateritic red soils has become the main obstacle for agricultural production in the south subtropical region. Due to the functions of soil pore, texture, and moisture improvements, earthworms have attracted much attention. However, due to the limitation of traditional and black box experimental methods, mechanisms and effects of earthworm activities on soil structure and soil moisture have not been fully quantified. This study combines situ field experiments, laboratory measurements, dye tracing and computed tomography (CT) scanning technique. We aim (1) to investigate the impact of earthworm activities on temporal and spatial variation of soil water and physical properties; (2) to analyze the infiltration and evaporation processes under different intensities of earthworm activities; and (3) to quantify the three dimensional structure of soil pores by using computed tomography (CT) scanning, and to elucidate the quantitative relationship between the evolution of soil structure and soil water movement. This research will contribute to a deeper understanding of the mechanisms about the effects of soil animal activities on water movement in lateritic red soils, and also provide scientific references for reasonable utilization of regional water and soil resources and the restoration of soil ecosystem.

南亚热带赤红壤的普遍粘重，以及“旱时一把刀，湿时一团糟”的水分特性成为农业生产的主要障碍。蚯蚓因具有改良土壤孔隙、质地、水分等功能而备受关注。局限于传统的、黑箱式的实验手段，以及土壤水分运动的复杂过程，蚯蚓活动及其对土壤结构、土壤水分的作用机制，还未完全实现定量化。为此，项目选择华南典型赤红壤为研究对象，通过田间小区和室内模拟试验，结合染色示踪、CT扫描与三维图像分析技术，研究蚯蚓活动下赤红壤土壤水分时空动态及物理性质变化特征，分析不同蚯蚓活动强度下土壤水分入渗、蒸发过程的变化规律，量化蚯蚓活动下土壤孔隙三维结构特征及差异，结合土壤基本物理性质，探究蚯蚓活动对土壤水分运动过程的影响机制。研究结果一方面有助于深化认识土壤动物活动下土壤水分演变机制，另一方面可为区域水土资源的合理利用和土壤生态系统恢复提供科学依据。

蚯蚓活动对土壤结构及土壤水分运动过程有着重要影响，本项目按照项目计划书开展相关研究工作，以华南典型赤红壤为研究对象，选择华南地区优势蚓参状远盲蚓（Amynthas aspergillum）和赤子爱胜蚓（Eisenia foetida）作为供试蚯蚓，通过田间小区和室内模拟试验，获得了接种蚯蚓后大量土壤结构、水分变化相关数据和资料。明确了不同类型蚯蚓活动下赤红壤土壤水分时空动态及物理性质变化特征，分析了不同蚯蚓活动强度下土壤水分入渗、蒸发过程的变化规律。利用CT扫描技术，结合三维图像处理软件，定量描述了不同蚯蚓活动强度下孔隙分布动态特征及差异，阐明了蚯蚓活动对土壤孔隙结构的影响程度。分析了蚯蚓大孔隙与土壤水分运动的定量关系，结合土壤基本物理性质变化，揭示了蚯蚓活动对赤红壤水分运动过程的作用机制。研究结果对深入认识蚯蚓活动与土壤水文过程关系具有重要意义，为区域水土资源的合理利用及土壤生态系统恢复提供科学依据。在该项目的支持下，目前发表科研论文5篇，其中SCI收录4篇（第一标注SCI论文3篇），中文核心期刊1篇。