In the purple hilly region, erosions and landslides are all serious, and it is of great scientific value and practical significance to study their formation mechanism and distribution features there. In this paper, so...In the purple hilly region, erosions and landslides are all serious, and it is of great scientific value and practical significance to study their formation mechanism and distribution features there. In this paper, soil micromorphological methods and techniques were used to study the erosion zonal distribution in the region. The results indicated: (1) According to erosion process, the spacial distribution zones of the erosions and landslides in the purple hilly region with different solums were divided into scouring erosion zone, transport-diffusion zone, rocks and soil turbulence zone and sediment-bury zone; (2) The soil micromorphologic taxonomic feature identifying different erosion-landslide zone were found by studying the soil micromorphology of erosive zone in purple hilly region; (3) As for the erosion–landslide formation in the region, besides the external factors, the internal factors were found more important and favorable for landslide formation through the studies on the micormorphological features of slide soil.展开更多
The level-trench method is a traditional tillage operation to develop a drainage system on slope land in the Three Gorges region. Before crops are planted, farmers prepare the land with level trenches spaced 3-1o m ap...The level-trench method is a traditional tillage operation to develop a drainage system on slope land in the Three Gorges region. Before crops are planted, farmers prepare the land with level trenches spaced 3-1o m apart, depending on the slope gradient: steeper slopes require shorter distances. Little scientific analysis has been done on the use of traditional level trenches for soil conservation. We conducted a field investigation and simulation experiments, and present a comparison between the spacing of level trenches and the slope length required for rill initiation. The results indicate that the spacing of level trenches in farmland is close to the slope length required for rill initiation in the experimental plots, and regression models of trench spacing with the gradient and the slope length required for rill initiation with the gradient have similar formats; the coefficients of determination (R2) for the two equations are 0.99 and 0.88, respectively. There were some differences between the field survey and experiments, but we conclude that the traditional level-trench method has an important role in preventing rill initiation.展开更多
本文以典型的衡阳紫色土丘陵坡地不同植被恢复阶段为研究对象,采用空间代替时间序列方法,选用立地条件基本相似的草坡阶段(Grassplot,GT)、灌草阶段(Frutex and grassplot,FG)、灌丛阶段(Frutex,FX)和乔灌阶段(Arbor and frutex,AF),通...本文以典型的衡阳紫色土丘陵坡地不同植被恢复阶段为研究对象,采用空间代替时间序列方法,选用立地条件基本相似的草坡阶段(Grassplot,GT)、灌草阶段(Frutex and grassplot,FG)、灌丛阶段(Frutex,FX)和乔灌阶段(Arbor and frutex,AF),通过调查取样和实验分析,对不同植被恢复阶段的土壤酶、养分与微生物及其相关性进行了研究。结果表明,1)随着恢复阶段的演替,脲酶、多酚氧化酶、蔗糖酶与过氧化氢酶的活性显著增加,在每个恢复阶段,脲酶、多酚氧化酶、蔗糖酶与过氧化氢酶活性随着土层的加深而逐渐减弱,脲酶与多酚氧化酶、蔗糖酶与过氧化氢酶活性呈显著正相关关系,蔗糖酶与脲酶和多酚氧化酶呈极显著正相关。2)随着恢复阶段的演替,土壤养分的时空变化与土壤酶活性的变化趋势基本一致,土壤有机碳、全氮与碱解氮含量呈上升趋势,土壤pH随植被恢复和演替而降低,随土壤深度的增加而上升,与土壤酶活性的变化趋势相反;脲酶与有机碳、全氮、碱解氮呈极显著正相关,与pH呈显著负相关,多酚氧化酶与有机碳、碱解氮呈极显著正相关,与全氮、速效磷、速效钾呈显著正相关,与pH呈显著负相关,蔗糖酶活性与有机碳、全氮、碱解氮、速效磷、速效钾呈显著正相关。3)不同恢复阶段土壤细菌数量最多,真菌数量和放线菌数量与细菌数量的变化趋势各不相同;细菌平均数量为AF>FX>FG>GT,真菌数量为FG>GT>FX>AF,放线菌数量为GT>FX>FG>AF。4)主成分分析揭示脲酶与多酚氧化酶可作为衡阳紫色土丘陵坡地土壤质量评价的指标。研究结果将丰富该地区植物生态学与恢复生态学的内容,为衡阳紫色土丘陵坡地生态系统的恢复与重建提供了重要依据。展开更多
基金supported by the Knowledge Innovation Project of the Chinese Academy of Sciences(KZCX3-SW-330)the State Natural Science Foundation for Outstanding Personnel of China(40025103)
文摘In the purple hilly region, erosions and landslides are all serious, and it is of great scientific value and practical significance to study their formation mechanism and distribution features there. In this paper, soil micromorphological methods and techniques were used to study the erosion zonal distribution in the region. The results indicated: (1) According to erosion process, the spacial distribution zones of the erosions and landslides in the purple hilly region with different solums were divided into scouring erosion zone, transport-diffusion zone, rocks and soil turbulence zone and sediment-bury zone; (2) The soil micromorphologic taxonomic feature identifying different erosion-landslide zone were found by studying the soil micromorphology of erosive zone in purple hilly region; (3) As for the erosion–landslide formation in the region, besides the external factors, the internal factors were found more important and favorable for landslide formation through the studies on the micormorphological features of slide soil.
基金supported by the Ministry of Science and Technology of China (Grant No.2011BAD31B03)the Ministry of Environment of China (Grant No.2009ZX07104-002-06)
文摘The level-trench method is a traditional tillage operation to develop a drainage system on slope land in the Three Gorges region. Before crops are planted, farmers prepare the land with level trenches spaced 3-1o m apart, depending on the slope gradient: steeper slopes require shorter distances. Little scientific analysis has been done on the use of traditional level trenches for soil conservation. We conducted a field investigation and simulation experiments, and present a comparison between the spacing of level trenches and the slope length required for rill initiation. The results indicate that the spacing of level trenches in farmland is close to the slope length required for rill initiation in the experimental plots, and regression models of trench spacing with the gradient and the slope length required for rill initiation with the gradient have similar formats; the coefficients of determination (R2) for the two equations are 0.99 and 0.88, respectively. There were some differences between the field survey and experiments, but we conclude that the traditional level-trench method has an important role in preventing rill initiation.
文摘本文以典型的衡阳紫色土丘陵坡地不同植被恢复阶段为研究对象,采用空间代替时间序列方法,选用立地条件基本相似的草坡阶段(Grassplot,GT)、灌草阶段(Frutex and grassplot,FG)、灌丛阶段(Frutex,FX)和乔灌阶段(Arbor and frutex,AF),通过调查取样和实验分析,对不同植被恢复阶段的土壤酶、养分与微生物及其相关性进行了研究。结果表明,1)随着恢复阶段的演替,脲酶、多酚氧化酶、蔗糖酶与过氧化氢酶的活性显著增加,在每个恢复阶段,脲酶、多酚氧化酶、蔗糖酶与过氧化氢酶活性随着土层的加深而逐渐减弱,脲酶与多酚氧化酶、蔗糖酶与过氧化氢酶活性呈显著正相关关系,蔗糖酶与脲酶和多酚氧化酶呈极显著正相关。2)随着恢复阶段的演替,土壤养分的时空变化与土壤酶活性的变化趋势基本一致,土壤有机碳、全氮与碱解氮含量呈上升趋势,土壤pH随植被恢复和演替而降低,随土壤深度的增加而上升,与土壤酶活性的变化趋势相反;脲酶与有机碳、全氮、碱解氮呈极显著正相关,与pH呈显著负相关,多酚氧化酶与有机碳、碱解氮呈极显著正相关,与全氮、速效磷、速效钾呈显著正相关,与pH呈显著负相关,蔗糖酶活性与有机碳、全氮、碱解氮、速效磷、速效钾呈显著正相关。3)不同恢复阶段土壤细菌数量最多,真菌数量和放线菌数量与细菌数量的变化趋势各不相同;细菌平均数量为AF>FX>FG>GT,真菌数量为FG>GT>FX>AF,放线菌数量为GT>FX>FG>AF。4)主成分分析揭示脲酶与多酚氧化酶可作为衡阳紫色土丘陵坡地土壤质量评价的指标。研究结果将丰富该地区植物生态学与恢复生态学的内容,为衡阳紫色土丘陵坡地生态系统的恢复与重建提供了重要依据。