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土林地貌是指在干旱-半干旱地区, 由半松散-半固结的碎屑沉积物经过流水剥蚀、堆积形成的林柱状、墙状及沟谷等一系列地貌的统称。以往对土林的研究不够系统和全面, 甚至将其归为黄土地貌。本文通过统计土林地貌在全世界范围内的分布, 分析研究了土林地貌的分布规律、物质组成和形成原因, 认为土林地貌具有自身独特的形成规律和形态特征。土林地貌从物质组成和形态上属于沉积岩地貌; 从成因上划分应属于剥蚀地貌中的流水剥蚀地貌, 并伴随有流水堆积地貌的特征, 其中剥蚀地貌进一步划分为沟谷地貌、林柱地貌和潜蚀地貌。  相似文献   
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南亚热带森林凋落物对土壤呼吸的贡献及其影响因素   总被引:9,自引:0,他引:9  
Three main types of Soil respirations(S+L and S) in southern subtropical forests in Dinghushan biosphere reserve were consecutively being monitored over 31 months by the approach of static chamber-gas chromatograph techniques. Research shows that: annual mean contribution rates of litter-fall to soil respiration in the monsoon evergreen broadleaf forest (BF), mixed broadleaf-coniferous forest (MF) and coniferous(pine) forest (PF) reached 27.82%、33.29%和36.35% respectively; Moreover, all three types of forests displayed the same seasonal dynamic features with the peaks contributions of them were from April to September, which accounts for 71.87%、61.89% and 70.39% of annual total contributions of litter fall to soil respiration respectively. Soil respiration(S+L) had an obviously positive relationship with the seasonal changes of litter-fall input(P<0.001; And soil water content had a significant impact on the contribution of litter-fall to soil respiration in the three types of forests (P<0.001); Soil temperature had positive correlativity with soil respiration flux, though it has no distinctive relationship with contribution of litter-fall to soil respiration; the contribution ratios of litter-fall to soil respiration on rainy days were 28.63%、38.20% and 40.12% respectively, which were significantly higher than those in the sunny days in the three types of forests.  相似文献   
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本文应用灰色系统理论,对白沙灌区流域降雨径流关系,白沙水量平衡站的潜水蒸发量与地下水位埋深关系作了关联度计算分析,对潜水蒸发量,各月之间的关系作了关联矩阵分析,均取得较满意成果.另对人民胜利渠灌溉作出最优决策,经过两年的实践检验,证明效果良好.  相似文献   
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