Nutrient Exports Under Different Harvesting Regimes in Two Types of Larch Plantation with Different Age in Northeastern China
Hongfeng Wang,
Xueyun Dong,
Yajuan Xing,
Zhengquan Wang,
Guoyong Yan,
Jianyu Wang,
Qinggui Wang
Issue:
Volume 5, Issue 6, December 2016
Pages:
67-77
Received:
29 October 2016
Accepted:
29 November 2016
Published:
29 December 2016
DOI:
10.11648/j.jenr.20160506.11
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Abstract: It has been confirmed in studies conducted in different regions and forest types that the harvesting regime has a significant impact on the export of nutrients from a plantation. Through establishing allometric growth equations and studying nutrient distribution patterns, the amounts of nutrients exported from larch (Larix spp.) plantations with different stand ages under different harvesting regimes (removal of stem wood, branches and bark (Rsbb), removal of stem wood and bark (Rsb), and removal of stem wood (Rs)) were determined in the present study. The results showed the following: 1) the organs of 20-year-old and 40-year-old larch trees exhibited basically the same nutrient distribution pattern. However, due to the difference in biomass partitioning in trees of these ages, they showed a significant difference in the cumulative amounts of nutrients in their organs. Specifically, the cumulative amounts of nutrient elements in the leaves and old branches of 20-year-old larch trees were significantly higher than in 40-year-old larch trees. However, the cumulative amounts of various nutrients in the xylem of the trunks of 20-year-old larch trees were significantly lower than in 40-year-old larch trees. 2) Compared with the Rsbb20, Rsbb40 or Rsb20 could result in significant decreases in the annual mean amounts of nutrients exported, the ratio of the annual mean total amount of nutrients exported to the annual net cumulative total amount of nutrients and the proportion of soil nutrients in the 0-30 cm soil layer. Changing the Rsbb20 to an Rsb40 or an Rs40 could further reduce the annual mean amounts of nutrients exported, the ratio of the annual mean total amount of nutrients exported to the annual net cumulative total amount of nutrients and the proportion of soil nutrients in the 0-30 cm soil layer. 3) Among the examined harvesting regimes, the Rs20 resulted in the lowest annual mean amounts of nutrients being exported. However, there was no significant difference in the annual mean amounts of nutrients exported between the Rs20 and the Rs40. The amounts of N, Ca and Mg exported under the Rs20 were slightly higher than under the Rs40, whereas the amounts of P and K exported under the Rs20 were slightly lower than under the Rs40. Hence, the harvesting regime is an important factor that results in the export of system nutrients and a decline in soil fertility. Therefore, prolonging the harvesting cycle and adopting Rs are two options for reducing the nutrients export.
Abstract: It has been confirmed in studies conducted in different regions and forest types that the harvesting regime has a significant impact on the export of nutrients from a plantation. Through establishing allometric growth equations and studying nutrient distribution patterns, the amounts of nutrients exported from larch (Larix spp.) plantations with di...
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Macro-economics Policies and Deforestation in Côte d’Ivoire
Issue:
Volume 5, Issue 6, December 2016
Pages:
78-91
Received:
17 November 2016
Accepted:
1 December 2016
Published:
6 January 2017
DOI:
10.11648/j.jenr.20160506.12
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Abstract: The development of Côte d’Ivoire is due to the agricultural sector at the expense of forest land. The objective of this study was, first, to describe the characteristics of agriculture and agricultural practices as well as their consequences on deforestation; secondly, to deal with macroeconomic policies, their impact on deforestation and on the environment, and their impacts assessment methodologies; but also to illustrate the opportunities available to the Ivorian agriculture. The results of our study indicated that the country had abundant natural resources (forest land) which have not been rationally managed. The majority of the population was rural, possessing many small farms. The agriculture sector was diverse regarding crops and production systems of which the most dominant was the traditional or extensive system. This sector is very important for the economy of the country, from the standpoint of revenue provided to the State and the significant number of jobs created. Agricultural practices have not been able to ensure a sustainable management of natural resources of the country, including the conservation of primary forests now fast disappearing. For the development of the agricultural sector induced by macroeconomic policies was made at the expense of forest land. Population growth impacts negatively also on the deforestation. This enables us to advance that introduced policies to revive the economy have only increased the extensive production system, which leads to deforestation and ecological imbalance. Despite all the investment in the agricultural sector, crops were only 38% of their potential. The environmental annual costs were estimated at 2.72% of 2015 GDP, or 545 billion CFA francs. This is a significant financial loss for an economy of an undeveloped country. However there is hope due to the opportunities offered by the intensification of the agriculture sector. Identifying determinants or causes of deforestation and presentation of opportunities would help the government adjust its resources for future forest recovery projects in order to significantly revitalize the agriculture and forest sector which is the main pillar of the country’s economy and the principal provider of employment. One advantage of this strategy will be to considerably decrease the rural exodus, and improve the government incomes.
Abstract: The development of Côte d’Ivoire is due to the agricultural sector at the expense of forest land. The objective of this study was, first, to describe the characteristics of agriculture and agricultural practices as well as their consequences on deforestation; secondly, to deal with macroeconomic policies, their impact on deforestation and on the en...
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Current Overview of Renewable Energy Resources in Rwanda
Jean de Dieu Uwisengeyimana,
Ahmet Teke,
Turgay Ibrikci
Issue:
Volume 5, Issue 6, December 2016
Pages:
92-97
Received:
22 June 2016
Accepted:
4 July 2016
Published:
21 January 2017
DOI:
10.11648/j.jenr.20160506.13
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Abstract: This paper reviews the energy sector in Rwanda with an accent on Renewable Energy. In Rwanda, energy sector plays a vital role in supporting socio-economic evolution and has a close connection to the growth of other economic sectors. The country has both renewable and non-renewable energy sources. Energy policies of the country give special attention to the use of modern, clean and energy efficient technologies. Most of Electricity in Rwanda comes from renewable sources: The total currently installed electricity capacity is 160 MW (March 2015), of which approximately more than 60% comes from hydrological resources along with other indigenous sources and less than 40% comes from diesel-powered generators. The current on-grid access to electricity is estimated at 23% of households and off-grid is 1.5%. Rwanda has envisaged increasing electric power supply by maximizing use of various indigenous energy resources and reach its ambitious target of 563 MW (domestic generation + imports) with electricity access of 70% (on-grid and off-grid) by the end of 2018. However, several challenges laying behind the development in the electric energy sector and utilization of renewable energy resources should be addressed. Challenges to be tackled and measures to be taken to achieve this goal have been presented in this study.
Abstract: This paper reviews the energy sector in Rwanda with an accent on Renewable Energy. In Rwanda, energy sector plays a vital role in supporting socio-economic evolution and has a close connection to the growth of other economic sectors. The country has both renewable and non-renewable energy sources. Energy policies of the country give special attenti...
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