In agricultural catchments where groundwater (GW) base flow discharge contributes substantially towards stream flow, the information linking GW inflow/outflow with contaminant import/export is scarce. However, this in...In agricultural catchments where groundwater (GW) base flow discharge contributes substantially towards stream flow, the information linking GW inflow/outflow with contaminant import/export is scarce. However, this information is essential to address aquatic ecosystem health hazard/risk associated with nitrate export and subsequent loading in sensitive surface water bodies (SWB). The objectives of this study were to assess the temporal dynamics of (i) rain water inflow/outflow behaviour in three agricultural catchments in the humid tropics of far-northeast Queensland of Australia, (ii) solute import via inflow and subsequent export in outflow, and (iii) the association between GW inflow/outflow and solute import/export. Approximately 71% of the average seasonal rainfall percolated (inflow) into the porous basaltic regolith of the Johnstone River Catchment (JRC) compared with 44% into the alluvial regolith in the Mulgrave River Catchment (MRC) and 29% into the metamorphic regolith in the Tully River Catchment (TRC), respectively. The outflows from the basaltic, alluvial, and metamorphic regoliths were 56%, 36%, and 55% of the inflows, respectively. The cumulative nitrate import per season was 25 k/ha in the JRC compared with 11 kg/ha in MRC and 34 kg/ha in TRC. The corresponding exports were 24 kg/ha, 8 kg/ha 26 kg/ha in JRC, MRC, and TRC, respectively. The total dissolved solute (TDS) exports were 82%, 77%, 75%, of the corresponding imports in JRC, MRC, and TRC, respectively. Simple correlations indicated that nitrate export was positively correlated with the outflow in each one of the regolith and similar trends were observed between inflow and import. The import/export mass balance for nitrate shows that 73% to 96% of the imports were exported during the same rainy season, suggesting the potential for nitrate associated ecosystem health hazard/risk in sensitive SWB receiving the outflows.展开更多
我国对加工贸易进口豁免关税而不豁免非关税壁垒。在国际产业分工深度调整和变革的背景下,全球价值链贸易发展促使中间品进出口往来大量增加,中间品进口遭遇的非关税壁垒对加工贸易企业的影响增大。统计结果显示,我国技术性贸易壁垒(Tec...我国对加工贸易进口豁免关税而不豁免非关税壁垒。在国际产业分工深度调整和变革的背景下,全球价值链贸易发展促使中间品进出口往来大量增加,中间品进口遭遇的非关税壁垒对加工贸易企业的影响增大。统计结果显示,我国技术性贸易壁垒(Technical Barriers to Trade,TBT)主要分布于纺织服装、化纤制造、机械、机电与通信设备制造等重要的劳动密集型加工制造行业,并且不同产品间遭遇的TBT差异程度较大。通过交互匹配我国TBT数据、工业企业数据和海关产品进口数据,本文实证检验了我国加工贸易企业中间品进口遭遇的TBT对企业全要素生产率的影响。结果表明,我国设置的TBT通过提高进口中间品质量、扩大进口规模和来源地结构效应显著促进本土加工贸易企业生产率提升,并且对大型企业、外资企业、资本密集型、低污染以及东部地区加工贸易企业生产率提升的促进效应更大,此外该促进效应随着企业从事来料加工贸易份额减少而逐渐增强。本文补充了进口贸易政策影响加工贸易企业绩效的经验证据。展开更多
文摘In agricultural catchments where groundwater (GW) base flow discharge contributes substantially towards stream flow, the information linking GW inflow/outflow with contaminant import/export is scarce. However, this information is essential to address aquatic ecosystem health hazard/risk associated with nitrate export and subsequent loading in sensitive surface water bodies (SWB). The objectives of this study were to assess the temporal dynamics of (i) rain water inflow/outflow behaviour in three agricultural catchments in the humid tropics of far-northeast Queensland of Australia, (ii) solute import via inflow and subsequent export in outflow, and (iii) the association between GW inflow/outflow and solute import/export. Approximately 71% of the average seasonal rainfall percolated (inflow) into the porous basaltic regolith of the Johnstone River Catchment (JRC) compared with 44% into the alluvial regolith in the Mulgrave River Catchment (MRC) and 29% into the metamorphic regolith in the Tully River Catchment (TRC), respectively. The outflows from the basaltic, alluvial, and metamorphic regoliths were 56%, 36%, and 55% of the inflows, respectively. The cumulative nitrate import per season was 25 k/ha in the JRC compared with 11 kg/ha in MRC and 34 kg/ha in TRC. The corresponding exports were 24 kg/ha, 8 kg/ha 26 kg/ha in JRC, MRC, and TRC, respectively. The total dissolved solute (TDS) exports were 82%, 77%, 75%, of the corresponding imports in JRC, MRC, and TRC, respectively. Simple correlations indicated that nitrate export was positively correlated with the outflow in each one of the regolith and similar trends were observed between inflow and import. The import/export mass balance for nitrate shows that 73% to 96% of the imports were exported during the same rainy season, suggesting the potential for nitrate associated ecosystem health hazard/risk in sensitive SWB receiving the outflows.
文摘我国对加工贸易进口豁免关税而不豁免非关税壁垒。在国际产业分工深度调整和变革的背景下,全球价值链贸易发展促使中间品进出口往来大量增加,中间品进口遭遇的非关税壁垒对加工贸易企业的影响增大。统计结果显示,我国技术性贸易壁垒(Technical Barriers to Trade,TBT)主要分布于纺织服装、化纤制造、机械、机电与通信设备制造等重要的劳动密集型加工制造行业,并且不同产品间遭遇的TBT差异程度较大。通过交互匹配我国TBT数据、工业企业数据和海关产品进口数据,本文实证检验了我国加工贸易企业中间品进口遭遇的TBT对企业全要素生产率的影响。结果表明,我国设置的TBT通过提高进口中间品质量、扩大进口规模和来源地结构效应显著促进本土加工贸易企业生产率提升,并且对大型企业、外资企业、资本密集型、低污染以及东部地区加工贸易企业生产率提升的促进效应更大,此外该促进效应随着企业从事来料加工贸易份额减少而逐渐增强。本文补充了进口贸易政策影响加工贸易企业绩效的经验证据。
