Results 71 to 80 of about 819 (92)

黄土丘陵区农业生态系统能效及其提高途径

open access: yesShuitu Baochi Xuebao, 1994
以安塞纸坊沟流域为例,分析了黄土丘陵区农业生态系统中农田、人工林草地、畜牧业子系统能量投入与产出,指出提高本地区农业生态系统能效的途径在于:1.加强水土流失综合,建立稳定的水土保持型生态农业。2.改变广种薄收习惯,建设稳产高产基本农田。3.合理增加投入,实现高产优质高效。
梁一民 刘国彬
doaj   +2 more sources

Duncan-Chang Constitutive Model of Vetiver Root and Soil Matrix at Different Growth Stages [PDF]

open access: yes
[Objective] To investigate the constitutive relationship governing the entire failure process of root-soil matrixs. [Methods] By employing the Duncan-Chang model and conducting triaxial tests, a stress-strain constitutive relationship model was developed
JI Jinnan, WU Ruibin, YANG Yuzhe
core   +1 more source

黄土高原浅沟发育主要影响因素及其防治措施研究

open access: yesShuitu Baochi Xuebao, 2008
浅沟侵蚀是黄土丘陵沟壑区重要的侵蚀类型。该文阐释了浅沟与浅沟侵蚀的概念,并对黄土高原浅沟侵蚀的形成与发展演化过程进行了综述,重点分析了影响浅沟发生发展的主要因素,并在此基础上提出了减小浅沟侵蚀的可行性防治措施。
许建民
doaj  

土壤干化的水文生态效应

open access: yesShuitu Baochi Xuebao, 2007
应用土壤-植被-大气传输模型(SVAT-model)——CoupModel,对黄土丘陵沟壑区农地(马铃薯)、林地(刺槐林)、采伐迹地(刺槐被砍伐)和荒草地(天然灌草)的土壤水分变化进行了模拟。分析了不同植被覆盖条件下土壤干化程度、气候干旱和植被耗水对土壤干化的贡献率以及土壤干化的水文生态效应。研究结果表明:农地不存在土壤干化现象,刺槐林地、采伐迹地和荒草地均存在明显的土壤干层,以刺槐林地最为严重;气候干旱和植被过度耗水对土壤干化的贡献率分别为70.74%和29.26%,气候干旱是导致土壤干化的主要原因 ...
卫三平, 王力, 吴发启
doaj   +2 more sources

黄土丘陵沟壑区(Ⅲ)山坡地林草植被配置模式研究

open access: yesShuitu Baochi Xuebao, 2001
根据对黄土丘陵第三副区的3个流域林草植被状况调查和山坡地水、肥、光、温等在坡面的层面分布规律,自坡上而下依次提出了不同层面的林草植被优化配置模式及植物种,对本区林草植被建设具有现实意义.
任杨俊 赵光耀 李建牢 赵俊侠 梁其春
doaj  

[Incidence of neonatal asphyxia and contributing factors for the develpment of severe asphyxia in Hubei Enshi Tujia and Miao Autonomous Prefecture: a multicenter study]. [PDF]

open access: yesZhongguo Dang Dai Er Ke Za Zhi, 2019
Wu SY   +21 more
europepmc   +1 more source

Correlation between soil-water characteristic curve and collapsibility in undisturbed loess [PDF]

open access: yes
This study investigates the correlation between the soil-water characteristic curve (SWCC) of undisturbed loess and its collapsibility. Undisturbed loess soil samples, obtained from depths up to 30 meters below the surface in Chang’an District, Xi’an ...
Haiman WANG   +3 more
core   +1 more source

黄土丘陵沟壑区县域耕地变化驱动要素研究——以安塞县为例

open access: yesShuitu Baochi Xuebao, 2003
土地利用变化的驱动要素研究是当前土地利用/土地覆盖变化(LUCC)研究的热点和关键问题之一。黄土丘陵沟壑区因其严重的水土流失问题,成为全国实施退耕还林还草措施的重点区域之一。运用典型相关分析,通过对典型区安塞县耕地数量、耕地质量变化驱动要素的定量分析,探讨了县域耕地变化的驱动要素,并运用典型相关系数和冗余度分析,对诊断结果进行了检验。为进一步研究整个黄土高原地区实施退耕还林还草政策提供借鉴,为该区土地利用的合理调整和水土保持的有效实施服务。
张秋菊 傅伯杰 陈利顶 赵文武
doaj  

[Geographic spatial pattern of digestive system cancers in Yiwu city]. [PDF]

open access: yesZhejiang Da Xue Xue Bao Yi Xue Ban, 2017
Lou Z   +5 more
europepmc   +1 more source

Effects of Vegetation Restoration on Soil Infiltration and Runoff in the Gully Regions on the Loess Plateau [PDF]

open access: yes
[Objective] To study the effects of vegetation restoration on rainfall infiltration and runoff is of great theoretical and practical value for rational utilization of watershed water resources and ecological construction.
BAI Yungang   +4 more
core   +1 more source

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