搜索结果: 151-165 共查到“知识库 土壤地理学”相关记录184条 . 查询时间(1.062 秒)
The copper (Cu) content in 205 soil samples (0-20 cm) of Tibet, covering 5 soil classes, were analyzed. The results showed as follows: (1) the average content of Cu was 19.6 mg kg-1 (CV=49...
Abstract: Soil degradation, defined as lowering and losing of soil functions, is becoming more and more serious worldwide in recent decades, and poses a threat to agricultural production a...
Abstract: The accelerated urbanization has resulted in new soil erosion in the Loess Plateau region since the 1980s. A concept of urban erosion and its impacts on environment are discussed...
WANG Shao-qiang1, ZHOU Cheng-hu1, LI Ke-rang1, ZHU Song-li2, HUANG Fang-hong1
(1.The State Key Laboratory of Resources and Environment Information System, Institute of Geographic Scien...
The seasonal frozen soil on the Qinghai-Tibet Plateau has strong response to climate change, and its freezing-thawing process also affects East Asia climate. In this paper, the freezing so...
Total N, total P and organic matters content in floodplain soils of Xianghai Nature Reserve
2007/8/24
Soil sediment samples of 10 layers with a spacing of 10 cm each were collected in different floodplain zones adjacent to Huolin River in the Xianghai Nature Reserve, and contents of total ...
Soil quality and sustainable land use in urban-rural marginal area: a case study of Kaifeng
2007/8/24
Abstract: By using the basic theories of physical geography, land resources and ecology, this article analyzes the soil quality of the rural-urban marginal area in Kaifeng. Computer techni...
Abstract: Taking west Jilin Province as an example, this paper put forward the assessment index of salinization, and based on it, the authors present the distribution characteristics of sa...
Abstract: Based on the analyses of water interactions and water balance, this paper discusses the issues on the assessment and regulation of soil water resources, which lays the scientific basis for l...
Abstract: The Loess Plateau is well known to the world for its intense soil erosion. The root cause for river sedimentation of Yellow River (Huanghe) and its resultant "hanging river" in c...
我国科学家为稀土农用提供重要依据
2007/8/15
曾被业界炒得沸沸扬扬的农用稀土对农田生态系统的影响,最近终于有了答案。记者日前从国家自然科学基金委获悉,由基金委资助、中科院倪嘉赞院士主持的一项自然科学基金重大项目,“稀土农用的环境化学行为及生态、毒理效应”,对农用稀土的环境化学行为、农用稀土化合物低剂量长时间作用的毒理效应以及稀土生物效应的化学基础等问题,给出了科学的解释,为我国制定稀土农用的有关政策提供了科学依据。
该课题研究了农用稀土在...
管理措施是影响土壤质量演变的重要因素.分析和讨论了5、10、15年苹果园耕层(0―20 cm)和0―200 cm土壤有机碳、全氮、全磷、有效磷和硝态氮含量及其影响因素。结果表明,5年、10年和15年的塬面苹果园表层土壤有机碳依次为7.5、6.7和6.7 g/kg;全氮依次为0.94、0.85和0.83 g/kg;但土壤全磷和速效磷含量随着种植年限而增加,与5年苹果园相比,塬面10年苹果园土壤全磷、...
黄土高原复杂的地形条件因改变了土壤的基本性质而成为影响土壤锰素有效性的主要原因,本文研究了黄土沟壑区不同地形条件对锰的形态分布及其有效性的影响。结果表明,研究区土壤有效锰的含量因地形条件不同差异很大,有效锰在土壤剖面呈下降趋势,在塬面土壤含量最高,沟道土壤含量最低。交换态锰在塬面、梯田土壤含量较低,在坡地和沟道土壤含量较高;塬面、梯田和坡地土壤碳酸盐结合态和有机结合态锰的含量高于沟道土壤,氧化物结...
MOISTURE IN DIFFERENT SOIL LAYERS DEPENDING ON WEED DENSITY IN COTTON
moisture in different soil layers weeds cotton
2010/12/3
The main competitors of cotton during the crop production are annual late-spring weeds with some perennial species representing the second most important group. During the 1999-2001 period the effect ...