首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2篇
  免费   0篇
经济学   1篇
农业经济   1篇
  2016年   2篇
排序方式: 共有2条查询结果,搜索用时 62 毫秒
1
1.
Noa Srebrnik 《Applied economics》2016,48(48):4622-4634
In their work, Vegh and Vuletin have shown that statutory tax rates are acyclical in developed economies and procyclical in developing ones. This article extends their analysis by checking the interaction of statutory tax rates with countries’ external public debt. In general, we found that the value added tax rates are changed procyclically in both developed and developing countries (i.e. taxes are raised in bad times and reduced in good times). However, when the external debt is high, in the developing countries the procyclicality increases, while the opposite result holds for developed economies. This pattern occurs mainly in times of recession, when the need for loans is the highest. Although we found that there was a reduction in procyclicality after the 2000s, these findings pose a challenge to policy-makers, who should think of ways of dealing with lack of foreign funds in difficult times.  相似文献   
2.
Nitrogen (N) is unique among essential elements required for life, in that it must be fixed from the vast atmospheric reservoir before most organisms can use it. Prior to industrial nitrogen fixation, many agricultural systems were limited in their productivity by N. What sustained N in the ancient Hawaiian dryland (rain-fed) agricultural systems that lacked legumes or other known significant N inputs? N-fixation during sugarcane (Saccharum officinarum) growth and litter decomposition was examined in settings representing pre-European Hawaiian agriculture. We did not detect associative N-fixation during the growth of five Hawaiian sugarcane cultivars. In contrast, N-fixation during the decomposition of leaf and stalk material was important. We found that the depth of the mulch layer significantly affected N-fixation levels during decomposition; values of N-fixation in different depths of senesced leaf litter ranged from 0.69 to 1.36?gN/kg of litter integrated over the lifetime of decomposition. Compared to senesced leaf litter, N-fixation during decomposition of non-senesced leaf litter was ~77% and stalk material ~140% per unit mass. Peak rates of N fixation occurred between 200 and 400 days of decomposition, and ranged from 1.37 to 3.27?gN/kg/yr. Our empirical results were extrapolated to represent the traditional Hawaiian cropping system; we calculated N-fixation inputs of 4.8–39.0 kgN/ha/yr, with fixed N adding 17–40% of the amount of N added through litter. Findings indicate that significant N may be introduced into natural cropping systems through mulching practices and that small changes in practices greatly alter the total inputs. The use of mulch was likely an important source of N in pre-industrial settings and may be used in contemporary systems to reduce nitrogen fertilizer requirements.  相似文献   
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号