基于根系解剖结构的金沙江干热河谷土壤侵蚀速率估算

doi:10.13249/j.cnki.sgs.2012.04.492

摘要/Abstract

摘要：

基于侵蚀过程会导致树木生长环境变化,进而改变根系生长生理特征的基本研究思想,以金沙江干热河谷龙川江流域为典型区,从树根细胞解剖结构和组合特征的变异中提取土壤侵蚀信息,探索和发展了基于树木生理生态的土壤侵蚀研究新方法与技术。结果表明,不同侵蚀强度下根系的年轮分布特征不一致,其中偏心率大小顺序为：局部暴露根系>浅埋根系>完全暴露根系,且偏心率与根系以上土层厚度、暴露程度存在显著性相关;根系导管面积是反演侵蚀过程的敏感指标,早材导管面积的变异是确定根系暴露时间的重要依据之一;龙川江流域土壤流失厚度为1.47~4.47 mm/a,平均侵蚀模数约为3 692 t/（km²·a）。

关键词: 干热河谷, 土壤侵蚀, 赤桉(Eucalyptus camaldulensis), 根系, 解剖结构

Abstract:

Based on physiological responses of tree growth to environmental changes, the paper developed a new method to extract information of soil erosion from tree-root anatomical structures and cell features. A case study has been carried out in the Longchuanjiang Watershed, Dry-hot Valley of Jinsha River. The study results showed: ① Soil erosion led to eccentric growth of Eucalyptus roots. The samples are divided into roots exposed partially, roots buried shallowly, roots exposed absolutely, based on the erosion degrees. The eccentricity ratio of tree ring is 0.461±0.133、0.218±0.096、0.158±0.121 and the order is roots exposed partially>roots buried shallowly>roots exposed absolutely. There is significant correlation bewteen soil depth and the eccentricity of tree tring. ② Vessel area was a sensitive indicator for reconstructing soil erosion process, and abrupt variations of earlywood vessels size was one of the important evidences to date the first year of exposure. The area of vessel decreases in latewood, whereas there is no significant change in earlywood, fiber wall thickness increases (decrease of fiber volume). ③ The soil loss thickness is 1.47~4.47 mm/a, and the average erosion modulus is about (3692±1710) t/(km²·a), in Longchuanjiang Watershed. It is serious erosion based on the standards for classification and gradtion of soil erosion.

Key words: Dry-hot Valley, soil erosion, Eucalyptus camaldulensis, tree-root, anatomical structure

中图分类号:

S157

孙丽萍, 王小丹. 基于根系解剖结构的金沙江干热河谷土壤侵蚀速率估算[J]. 地理科学, 2012, 32(4): 492-498.

Li-ping SUN, Xiao-dan WANG. Evaluation of Soil Erosion Rate Based on Anatomical Structure of Treeroots — A Case Study in the Dry-hot Valley of Jinsha River[J]. SCIENTIA GEOGRAPHICA SINICA, 2012, 32(4): 492-498.

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	侵蚀类型	距树干距离	根系以上土层厚度	暴露厚度
浅埋根系	面蚀	0.234	-0. 506	-
局部暴露根系	面蚀	-0.355^*	-	0.405^**
完全暴露根系	沟蚀	0.141	-	-