Nutrient Discharges from a Typical Watershed in the Hilly Area of Subtropical China

来源 :土壤圈 | 被引量 : 0次 | 上传用户:sc13859315118
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
Agriculture is still the biggest contributor of non-point source (NPS) pollution to water bodies andrunoff discharges of nutrients and other chemicals are one of the most important pathways. This studywas conducted during 1998~1999 in a typical watershed with complex agriculture and forestry systems aswell as dotted farmer villages, in a transitional region between the mid- and northern subtropical zones ofChina. Continuous sampling of stream water was performed regularly at a weekly frequency, with additionalsampling after all major rainfall events. The discharges of N and P nutrients and suspended materials weremeasured and the total and area-averaged annual discharges of all components were calculated. The resultsshowed an uneven seasonal distribution of nutrient discharges with summer storms contributing most tothe total fluxes. This study demonstrated a high dependence of runoff volume on rainfall but the overallrunoff coefficients were dependent on land use type and watershed size. The area-averaged annual dischargesvaried greatly among the sub-watersheds with different sizes and land use structures. This is the first studyestimating the area-averaged annual discharges of N and P in the hilly areas of subtropical China, which were1.5 g m-2 a-1 and 0.1 g m-2 a-1, respectively, providing important reference values for the assessment ofregional agricultural non-point source pollution.
其他文献
随着市场经济的不断深化,市场对于中小企业的要求越来越高。中小企业在激烈的市场竞争中如何依靠适合自身发展的市场营销策略立足,成为越来越多研究者的研究议题。本文首先对市
建筑施工过程建设周期长,资金投入多,是控制工程造价、节约施工成本的关键阶段。工程招投标、合同的签订及管理、施工组织设计的审查以及材料管理等几个环节是此阶段造价控制的
工程经济的利润,是每个建筑企业追求的目标,能最大限度的获取利润,是每个施工企业扩大再生产的动力。建筑工程是我国近一段时期内国家大力扶持的行业,但同样,竞争也十分激烈。企业
雷帕霉素靶蛋白(mammalian target of rapamycin,mTOR)信号通路在胰腺癌中过度激活,可作为胰腺癌的靶向治疗的靶点。近年来研究显示,雷帕霉素及衍生物无论是单药使用还是和其他细
Objective To investigate apoptosis in vivo in patients with leukemia at different stages of the first cycle of chemotherapy.Methods We detected apoptosis of H
Bayesian approach is an important method in statistics. The Bayesian belief network is a powerful knowledge representation and reasoning tool under the conditio
The development of gastric cancer is a multi-factor process. In addition to genetic factors, environmental factors including smoking, low gastric acidity, exces
Discussed in the article are the factors for the imperfect quality of piecing based on the principles and the key technologies of semiautomatic piecing. Further
Soil and land degradation in the tropics can be identified and described in terms of physical, chemical,and biological changes from its pristine state brought a