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土层厚度对紫色土坡地生产力的影响 被引量:42
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作者 朱波 况福虹 +3 位作者 高美荣 汪涛 王小国 唐家良 《山地学报》 CSCD 北大核心 2009年第6期735-739,共5页
通过紫色土坡地土层厚度的调查与不同土层厚度的小区对比试验,研究紫色土薄层坡地的生产力特性。结果表明,约73%的紫色土坡耕地土层厚度为20~60cm。土层厚度是紫色土生产力的基本限制条件。土层越薄,作物株高、生物量和产量愈低,生产... 通过紫色土坡地土层厚度的调查与不同土层厚度的小区对比试验,研究紫色土薄层坡地的生产力特性。结果表明,约73%的紫色土坡耕地土层厚度为20~60cm。土层厚度是紫色土生产力的基本限制条件。土层越薄,作物株高、生物量和产量愈低,生产力愈低;土层越厚,生物量、产量愈高,生产力愈高,土层厚度的影响在玉米季尤为突出,20cm、40cm小区夏玉米产量仅为60cm小区的50%、74%,为80cm小区的28%、40%,100cm小区的23%、34%。当土壤厚度超过60cm,小麦、玉米的株高、生物量及根重差异不显著,而土壤蓄水可抵御紫色丘陵区连续20d的夏旱,因此,可初步判定60cm土层为紫色土生产力临界土层。60cm以上厚度的紫色土可维持基本稳定的生产力水平。 展开更多
关键词 紫色土 土层厚度 生产力 临界土层
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Research on the Critical Conditions for Clay Particle Release During Saline Aquifer Freshening Process 被引量:2
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作者 ZHENG Xilai CHEN Ran 《Journal of Ocean University of China》 SCIE CAS 2014年第4期628-636,共9页
Water sensitivity phenomenon occurs during saline aquifer freshening process in seawater intrusion area, and clay particles released in the phenomenon can damage the infiltration capacity of the aquifer. In order to f... Water sensitivity phenomenon occurs during saline aquifer freshening process in seawater intrusion area, and clay particles released in the phenomenon can damage the infiltration capacity of the aquifer. In order to find out the factors and mechanisms for clay particle release, laboratory column infiltration experiments simulating saline aquifer freshening process were designed to measure the critical conditions(critical flow velocity, critical salt concentration and critical ionic strength) and force analysis for clay particle according to DLVO electric double layer theory was employed to illustrate the mechanisms for particle release. The research results showed that critical flow velocity for clay particle release is influenced by salt concentration of injecting solution. When salt concentration of injecting solution is very high, clay particles are not released, indicating that there does not exist a critical flow velocity in this situation. As salt concentration of injecting solution decreases, particles start to be released. The critical salt concentration for clay particle release is 0.052 mol L-1 in our work, which was determined by a constant-flux experiment for stepwise displacement of high concentration Na Cl solution. The critical ionic strength for clay particle release decreases as Ca2+ molar content percentage of the mixed solution of Na Cl and Ca Cl2 increases following the first-order exponential decay equation y = 0.0391e-0.266 x + 0.0015. 展开更多
关键词 seawater intrusion area clay particle release critical flow velocity critical salt concentration critical ionic strength
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