论文部分内容阅读
地表糙度是影响地表径流和侵蚀过程的重要属性.生物结皮在干旱半干旱区广泛分布,是地表糙度的影响因子之一.本文采用链条法测定了黄土丘陵区不同发育阶段生物结皮表面糙度特征,分析了不同发育阶段生物结皮表面糙度对坡向、土壤含水量和冻融作用的响应及其与各理化性质的相关性,初步探索了生物结皮对地表糙度的影响及其相关因素.结果表明:生物结皮显著改变地表糙度,随着生物结皮从藻结皮向藓结皮演替,其糙度先降低后增加,生物结皮发育形成10年以后,其表面糙度基本趋于稳定;研究区早期形成的藻结皮表面糙度较裸土降低47.0%,深色藻结皮(藓类盖度<20%)较裸土降低20.4%,混生结皮(藓类盖度为20%~60%)和苔藓结皮(藓类盖度>70%)表面糙度与深色藻结皮基本一致;坡向对发育10年以上的生物结皮表面糙度的影响不显著;土壤含水量影响地表糙度特征.研究区浅色藻结皮表面糙度随水分变化较为剧烈;随着生物结皮发育,深色藻结皮、混生结皮和苔藓结皮表面糙度随水分的变化趋于平缓.冻融增加了生物结皮表面糙度.浅色藻结皮经两次冻融后表面糙度增加29.7%;深色藻结皮、混生结皮和藓结皮表面糙度的影响需经过反复冻融才有所体现.生物结皮表面糙度与藓结皮盖度呈显著正相关(P<0.1).
Surface roughness is one of the most important attributes that affect surface runoff and erosion process.Cobalt crust is widely distributed in arid and semiarid regions and is one of the most important factors affecting the surface roughness.In this paper, Surface roughness, the response of the roughness of the biological crust surface to aspect, soil moisture content and freeze-thaw action at different developmental stages and its correlation with physicochemical properties were analyzed. The effects of biological crusts on the surface roughness The results showed that: the biological crust significantly changed the surface roughness, with the biological crusts from algal crust to moss crust succession, the roughness decreased first and then increased, the development of biological crust formation after 10 years , The roughness of the surface basically stabilized. The surface roughness of algal crusts formed earlier in the study area decreased by 47.0% than that of bare soil and that of dark color algae (<20%) decreased by 20.4% The surface roughness of crusts (20% -60% moss coverage) and moss crusts (moss coverage> 70%) are basically the same as those of dark-colored algal crusts. The effect of surface roughness is not significant, and the soil moisture affects the surface roughness With the development of biological crusts, the surface roughness of dark-skin algal crusts, mixed crusts and moss crusts tends to be gentle with the changes of water content. The roughness of the skin surface of the light color algae crust increased by 29.7% after two freeze-thaw cycles. The influence of the surface roughness of dark-skin algal crusts, mixed crusts and moss crusts had to be repeated There was a significant positive correlation between the surface roughness of the biological crust and the coverage of the moss crust (P <0.1).