[Objective] To clarify the effects of different straw retention regimes on soil fertility in double cropping paddy field. [Method] The effects of different straw reten- tion regimes on total organic carbon （CToc）, a...[Objective] To clarify the effects of different straw retention regimes on soil fertility in double cropping paddy field. [Method] The effects of different straw reten- tion regimes on total organic carbon （CToc）, active carbon （CA） and mineralized carbon （CM） were analyzed, and carbon pool active （A）, carbon pool active index （A/）, carbon pool index （CPI） and carbon pool management index （CPMi） for each treat- ment were calculated. [Result] Compared with the unfertilized treatment （CK）, CToc, CA, CM and the available ratio of soil carbon were increased in the treatment of re- turning early season and late season rice straws to field. With the same nutrient application, CToc, CA and the available ratio of soil carbon in the field with straw re- turned to field were higher than that of straw incineration and no straw returning, and the change in soil CA content was more significant. The difference in CPMI be- tween different treatments reached significant or very significant level, and the value was in the order of straw directly returned to field 〉 straw returned to field after in- cineration 〉 no straw returned to field. [Conclusion] This study provided theoretical bases for the increase of soil CA content and soil fertility in double rice fields.展开更多
Schizostachyum dullooa （Gamble） Majumder ＇dolu bamboo＇ is a thin walled sympodial moderate sized to large tufted bamboo, dominant in the successional fallows of northeast India. The impact of resource management o...Schizostachyum dullooa （Gamble） Majumder ＇dolu bamboo＇ is a thin walled sympodial moderate sized to large tufted bamboo, dominant in the successional fallows of northeast India. The impact of resource management on productivity and sustainability of the species was evaluated by investigating the population status and regeneration in Cachar tropical semi evergreen forest under private property resource management （PPRM） and common property resource management （CPRM） regimes. Population status revealed current-year, one-year, two-year and three-year-old culms contribute 54%, 24%, 16% and 6% of the total culms per clump, respectively, under PPRM. Three-year-old culms were absent in CPRM and population status was thus represented by current year （83%）, one-year （16%） and two-year （1%） old culms. Net change, rate of change and % gain in population for different age classes showed the prevalence of management practices under CPRM was unscientific. Efficiency of new culm production per clump used as an index of regeneration was 69.7% in PPRM and 59.88% in CPRM. New culms produced under CPRM were small and thin. We conclude that CPRM is inappropriate for a long term economic and ecological sustainability of the species and alternative management protocols are needed for conservation of the species.展开更多
Recently, the area located within the Unfinished Obelisk (UO) archeological site showed numerous seepages and accumulations of groundwater in a small pond located a few meters from the Unfinished Obelisk. The Supreme ...Recently, the area located within the Unfinished Obelisk (UO) archeological site showed numerous seepages and accumulations of groundwater in a small pond located a few meters from the Unfinished Obelisk. The Supreme Council of Antiques sponsored integrated geological, geophysical, and hydrogeological studies to identify the possible sources of groundwater and the optimum technique to manage the groundwater flow system that may jeopardize this invaluable sculpture. The geological units and the prevailing structure have been studied in detail using Landsat imagery and field work over two consecutive seasons. The field studies indicated the development of several fault/joint systems oriented mainly ENE-WSW with clear indications of mineralization and intensive weathering effects along these fabrics. Several resistivity (vertical seismic profile and resistivity imaging) measurements extending down to at least 20 m depth and Radar imaging down to 10 m depth are gathered to investigate the extension of outcrop units and the dominant structures prevailing the near subsurface. Geophysical data indicated the development of at least three hydrostratigraphic units arranged from top to bottom as valley fill, fractured/weathered granite, and slightly fractured to massive granitic unit. In addition, the major faults mapped by resistivity images helped to locate several observation wells and a production well to test the transmissivity across the groundwater system. The results of a pumping test indicated very low aquifer conductivity and the development of an aquitard with preferential vertical flow at the study area. This enforces a local interference through a shallow underground drainage system with sump and pump to maintain low groundwater level at the UO-archeological site.展开更多
Forests in Kenya are managed under different management regimes, including traditional community based forest management, command and control, participatory forest management, leasehold, concessions, and private. Asse...Forests in Kenya are managed under different management regimes, including traditional community based forest management, command and control, participatory forest management, leasehold, concessions, and private. Assessment of these regimes’ impact (positively or negatively) on forest conservation has not been done. The study was done to determine the impact on forest conservation of three management regimes traditional community based forest management, command and control, and participatory forest management. The survey was done through secondary data, focus group discussion, key informant interview, household survey, ecological survey, and land cover and land use analysis through GIS. The results indicate that the forest site under participatory forest management witnessed better forest management. In this site, the forest zone witnessing best management was the one near the forest station where the rangers are located and adjacent to the community that has been involved in forest management and benefited most from project intervention, an incentive for their participation in forest management. The forests under traditional community based forest management faced a high forest degradation rate. Forest under command and control regime witnessed the best forest condition improvement attributed to the management regime not allowing consumptive forest resource utilization. Each regime was best under its’ legislative framework and would facilitate better forest management and contribute to improved livelihoods without compromising forest quality. Participatory forest management was the most preferred management regime contributing to better forest management, improved community livelihoods, and formally involved communities and other stakeholders. Each regime’s appropriateness would be enhanced through stakeholder capacity building, institutional reform, adequate financial facilitation, and appropriate implementation. Therefore, adopting participatory forest management attributes to the other two management regimes would enhance their appropriateness, while appreciating that the management objective determines the regime being implemented in each forest.展开更多
基金Supported by the National Key Technology R&D Program during the Eleventh Five-year Plan Period,China(2006BAD02A04)the Key Technology R&D Program of Jiangxi Province,China(2009BNA03800)~~
文摘[Objective] To clarify the effects of different straw retention regimes on soil fertility in double cropping paddy field. [Method] The effects of different straw reten- tion regimes on total organic carbon （CToc）, active carbon （CA） and mineralized carbon （CM） were analyzed, and carbon pool active （A）, carbon pool active index （A/）, carbon pool index （CPI） and carbon pool management index （CPMi） for each treat- ment were calculated. [Result] Compared with the unfertilized treatment （CK）, CToc, CA, CM and the available ratio of soil carbon were increased in the treatment of re- turning early season and late season rice straws to field. With the same nutrient application, CToc, CA and the available ratio of soil carbon in the field with straw re- turned to field were higher than that of straw incineration and no straw returning, and the change in soil CA content was more significant. The difference in CPMI be- tween different treatments reached significant or very significant level, and the value was in the order of straw directly returned to field 〉 straw returned to field after in- cineration 〉 no straw returned to field. [Conclusion] This study provided theoretical bases for the increase of soil CA content and soil fertility in double rice fields.
基金supported by the research grant from G.B. Pant Institute of Himalayan Environment and Development sponsored project
文摘Schizostachyum dullooa （Gamble） Majumder ＇dolu bamboo＇ is a thin walled sympodial moderate sized to large tufted bamboo, dominant in the successional fallows of northeast India. The impact of resource management on productivity and sustainability of the species was evaluated by investigating the population status and regeneration in Cachar tropical semi evergreen forest under private property resource management （PPRM） and common property resource management （CPRM） regimes. Population status revealed current-year, one-year, two-year and three-year-old culms contribute 54%, 24%, 16% and 6% of the total culms per clump, respectively, under PPRM. Three-year-old culms were absent in CPRM and population status was thus represented by current year （83%）, one-year （16%） and two-year （1%） old culms. Net change, rate of change and % gain in population for different age classes showed the prevalence of management practices under CPRM was unscientific. Efficiency of new culm production per clump used as an index of regeneration was 69.7% in PPRM and 59.88% in CPRM. New culms produced under CPRM were small and thin. We conclude that CPRM is inappropriate for a long term economic and ecological sustainability of the species and alternative management protocols are needed for conservation of the species.
文摘Recently, the area located within the Unfinished Obelisk (UO) archeological site showed numerous seepages and accumulations of groundwater in a small pond located a few meters from the Unfinished Obelisk. The Supreme Council of Antiques sponsored integrated geological, geophysical, and hydrogeological studies to identify the possible sources of groundwater and the optimum technique to manage the groundwater flow system that may jeopardize this invaluable sculpture. The geological units and the prevailing structure have been studied in detail using Landsat imagery and field work over two consecutive seasons. The field studies indicated the development of several fault/joint systems oriented mainly ENE-WSW with clear indications of mineralization and intensive weathering effects along these fabrics. Several resistivity (vertical seismic profile and resistivity imaging) measurements extending down to at least 20 m depth and Radar imaging down to 10 m depth are gathered to investigate the extension of outcrop units and the dominant structures prevailing the near subsurface. Geophysical data indicated the development of at least three hydrostratigraphic units arranged from top to bottom as valley fill, fractured/weathered granite, and slightly fractured to massive granitic unit. In addition, the major faults mapped by resistivity images helped to locate several observation wells and a production well to test the transmissivity across the groundwater system. The results of a pumping test indicated very low aquifer conductivity and the development of an aquitard with preferential vertical flow at the study area. This enforces a local interference through a shallow underground drainage system with sump and pump to maintain low groundwater level at the UO-archeological site.
文摘Forests in Kenya are managed under different management regimes, including traditional community based forest management, command and control, participatory forest management, leasehold, concessions, and private. Assessment of these regimes’ impact (positively or negatively) on forest conservation has not been done. The study was done to determine the impact on forest conservation of three management regimes traditional community based forest management, command and control, and participatory forest management. The survey was done through secondary data, focus group discussion, key informant interview, household survey, ecological survey, and land cover and land use analysis through GIS. The results indicate that the forest site under participatory forest management witnessed better forest management. In this site, the forest zone witnessing best management was the one near the forest station where the rangers are located and adjacent to the community that has been involved in forest management and benefited most from project intervention, an incentive for their participation in forest management. The forests under traditional community based forest management faced a high forest degradation rate. Forest under command and control regime witnessed the best forest condition improvement attributed to the management regime not allowing consumptive forest resource utilization. Each regime was best under its’ legislative framework and would facilitate better forest management and contribute to improved livelihoods without compromising forest quality. Participatory forest management was the most preferred management regime contributing to better forest management, improved community livelihoods, and formally involved communities and other stakeholders. Each regime’s appropriateness would be enhanced through stakeholder capacity building, institutional reform, adequate financial facilitation, and appropriate implementation. Therefore, adopting participatory forest management attributes to the other two management regimes would enhance their appropriateness, while appreciating that the management objective determines the regime being implemented in each forest.
