喀斯特灌木林枯落物持水特性分析

灌木是喀斯特地区的主要植被类型之一,研究其枯落物的持水特性对喀斯特地区水源涵养和生态修复具有重要意义。为了解不同灌木群落和坡位的枯落物持水能力,采用室内浸泡法和烘干法,分析了3种灌木群落和处于3种不同坡位的混合灌木林枯落物的持水能力。结果表明:3种灌木群落枯落物的总蓄积量表现为球核荚蒾圆果化香月月青,3种坡位群落枯落物的总蓄积量表现为坡下坡中坡上;无论群落或是坡位,枯落物蓄积量均表现为半分解层大于未分解层;群落最大持水量为圆果化香月月青球核荚蒾,不同坡位最大持水量为坡中坡下坡上;圆果化香的持水能力较强,坡中的持水能力较好;不同群落和不同坡位的枯落物持水量与浸泡时间都存在对数关系,吸水速率与浸泡时间存在幂函数关系。     

砒砂岩区区位特征分析及植被建设探讨

晋陕蒙接壤地区的砒砂岩区,面积约1.5万km~2,广泛出露或浅伏二迭纪至白垩纪碎屑沉积岩,土层厚度大部分为3～20cm,且质地粗疏,植被资源匮乏,覆盖度仅30％左右,加之干旱少雨、风沙严重,年侵蚀模数为5000～15000t/km~2。植被建设应从提高植被整体功能出发,由单纯的生态型向生态经济型植被发展,以全面建设经营性草灌(木)植被、集约经营轮作作物植被、合理配置防御性乔木植被为重点。主要技术途径是合理开发现有植物资源,积极引进区外植物种类,大力试验、推广植物篱技术。     

湿润喀斯特地区冬季灌丛土壤水分对降雨的响应

为分析湿润喀斯特地区冬季灌丛土壤水分对降雨响应的规律,基于实地逐日监测记录的灌丛土壤水分和降雨数据,对冬季灌丛土壤水分与降雨的响应关系进行分析.结果 表明:小于5.80 mm的12场小降雨事件对土壤水分无法进行有效补给,大于20 mm的2场降雨事件能够有效补给土壤水分,土壤水分的响应时间随着降雨量的增加而加快.根据土壤...     

Spatial distribution and drivers of throughfall beneath shrub canopies in a semi-arid desert steppe

The spatial distribution of water is mainly controlled by the vegetation canopy, which determines the partitioning of rainfall into interception, throughfall (TF) and stemflow. TF is known to be a critical component of hydrological and biogeochemical cycles. Spatiotemporal patterns of TF have been studied in different ecosystems, although the majority of studies focused on forests. Few reports on small-scale TF variability and drivers in semi-arid desert steppes have been published. Herein, we investigated the variability of TF of two morphologically distinct artificial revegetation shrubs (Caragana liouana and Salix psammophila) within a semi-arid desert steppe, synthesized the data and analysed the characteristics of TF distribution and drivers at the rainfall event scales. We found that (1) morphological differences were sufficient to generate significant (p < 0.05) differences in TF between the two shrub species under the same rainfall and meteorological conditions, with a TF percentage of 70.22% for C. liouana and 79.87% for S. psammophila; (2) a linear outward radical increase in TF was identified with increasing distance from the base of the isolated shrubs. Wind speed had a greater effect on the distribution of TF beneath the shrub structure for C. liouana, whereas the distribution of TF beneath the shrub structure for S. psammophila was more affected by wind direction; and (3) canopy architecture, in particular the stem angle and canopy base area, which affected the openness of the canopy and played an important role in the distribution of TF in the two shrubs. The results reveal the key factors driving water use under rainfall during revegetation and the TF utilization mechanism in semi-arid areas and highlight the complementary effect of different species on ecosystem hydrological functions.