Triple cropping in the inland valleys of southwestern Nigeria is technically possible but the third crop between the main crop and vegetables has poor establishment due to soil saturation. Identification of appropriat...Triple cropping in the inland valleys of southwestern Nigeria is technically possible but the third crop between the main crop and vegetables has poor establishment due to soil saturation. Identification of appropriate sowing methods is required in this niche. A field experiment was conducted at the University of Agriculture, Abeokuta, Nigeria in 2007/2008 and 2008/2009 cropping seasons to evaluate the effect of sowing methods on the performance of upland rice （Oryza spp.） in a lowland rice-vegetable sequence. The first, second, and third crops in the sequence were planted in May, September and December, respectively. Two upland rice varieties, namely New Rice for Africa 1 （NERICA 1） and ITA 150 constituted the main plot treatments while the subplot treatments were sowing methods. The mean grain yield of lowland rice for two years was 7.74 t ha^-1. The fluted pumpkin had a fresh leaf weight of 14.78 t ha^-1. The grain yields of the two upland rice varieties （1.81 and 1.85 t ha^-1） and sowing methods which ranged between 1.63 and 2.05 t ha^-1 were similar in both cropping seasons. However, the interaction of variety by sowing methods had a significant effect on grain yield. Transplanting and pre-germinated broadcast had the highest grain yield for NERICA 1 while dry broad cast and pre-germinated dibbled had the highest in ITA 150. Hence, the productivity of triple cropping in the inland valley was enhanced by sowing methods.展开更多
In Ghana, inland valleys have been found to be suitable for rice cultivation and could potentially increase lowland paddy rice production, This study estimated the temporal variations of surface water resources and th...In Ghana, inland valleys have been found to be suitable for rice cultivation and could potentially increase lowland paddy rice production, This study estimated the temporal variations of surface water resources and their spatial distribution in the Mankran watershed of Ghana through the collection of recorded hydrological data in the bench mark watershedfrom2008 to 2010. Since most inland valley rice cultivation highly depends on rainfall, the watershed precipitation data over a decadal period showed sufficient wet years with a potential to sustain a high cultivation of paddy rice. Peak wetness occurred in June and October over a bi-modal precipitation pattern. Rating curve data for the Mankran-kesse river-upstream depicted low discharge values despite having a higher stream order. Thus stream order alone was not sufficient to estimate water resources potential. It was presumed that the geomorphology and lithology of the highly porous river bed and the presence of high sub-surface water resources stored in this zone may be implicated for this observation. Provision of water storage options for zones like Kesse-upstream seems a feasible option in order to cater for supplementary irrigation while indirectly tapping on subsurface water resources stored in the porous aquifers through basin interflows. Base flow data also showed that the discharge from upstream locations to the downstream exit of the watershed was high through direct surface river discharge and subsurface interflow. The temporal patterns of the hydrology indicate that annual paddy rice cultivation is ideal between May and October.展开更多
Global warming as a result of rapid increase in atmospheric COa emission is significantly influencing world＇s economy and human activities. Carbon sequestra- tion in phytoliths is regarded as a highly stable carbon s...Global warming as a result of rapid increase in atmospheric COa emission is significantly influencing world＇s economy and human activities. Carbon sequestra- tion in phytoliths is regarded as a highly stable carbon sink mechanism in terrestrial ecosystems to mitigate climate change. However, the response of plant phytolith-occluded carbon （PhytOC） to external silicon amendments remains unclear. In this study, we investigated the effects of basalt powder （BP） amendment on phytolith carbon sequestration in rice （Oryza sativa）, a high-PhytOC accumulator. The results showed that the contents of phytolith and PhytOC in rice increased with BP amendment. The PhytOC produc- tion flux in different rice plant parts varied considerably （0.005-0.041 Mg CO_2 ha^-1 a^-1）, with the highest flux in the sheath. BP amendment can significantly enhance flux of phytolith carbon sequestration in croplands by 150 %. If the global rice cultivation of 1.55 × 10^8 ha had a similar flux of PhytOC production in this study, 0.61× 10^7 to 1.54 × 10^7 Mg CO_2 would be occluded annually within global rice phytoliths. These findings highlight that exter- nal silicon amendment such as BP amendment represents an effective potential management tool to increase long- term biogeochemical carbon sequestration in crops such as rice and may also be an efficient way to mitigate the global warming indirectly.展开更多
文摘Triple cropping in the inland valleys of southwestern Nigeria is technically possible but the third crop between the main crop and vegetables has poor establishment due to soil saturation. Identification of appropriate sowing methods is required in this niche. A field experiment was conducted at the University of Agriculture, Abeokuta, Nigeria in 2007/2008 and 2008/2009 cropping seasons to evaluate the effect of sowing methods on the performance of upland rice （Oryza spp.） in a lowland rice-vegetable sequence. The first, second, and third crops in the sequence were planted in May, September and December, respectively. Two upland rice varieties, namely New Rice for Africa 1 （NERICA 1） and ITA 150 constituted the main plot treatments while the subplot treatments were sowing methods. The mean grain yield of lowland rice for two years was 7.74 t ha^-1. The fluted pumpkin had a fresh leaf weight of 14.78 t ha^-1. The grain yields of the two upland rice varieties （1.81 and 1.85 t ha^-1） and sowing methods which ranged between 1.63 and 2.05 t ha^-1 were similar in both cropping seasons. However, the interaction of variety by sowing methods had a significant effect on grain yield. Transplanting and pre-germinated broadcast had the highest grain yield for NERICA 1 while dry broad cast and pre-germinated dibbled had the highest in ITA 150. Hence, the productivity of triple cropping in the inland valley was enhanced by sowing methods.
文摘In Ghana, inland valleys have been found to be suitable for rice cultivation and could potentially increase lowland paddy rice production, This study estimated the temporal variations of surface water resources and their spatial distribution in the Mankran watershed of Ghana through the collection of recorded hydrological data in the bench mark watershedfrom2008 to 2010. Since most inland valley rice cultivation highly depends on rainfall, the watershed precipitation data over a decadal period showed sufficient wet years with a potential to sustain a high cultivation of paddy rice. Peak wetness occurred in June and October over a bi-modal precipitation pattern. Rating curve data for the Mankran-kesse river-upstream depicted low discharge values despite having a higher stream order. Thus stream order alone was not sufficient to estimate water resources potential. It was presumed that the geomorphology and lithology of the highly porous river bed and the presence of high sub-surface water resources stored in this zone may be implicated for this observation. Provision of water storage options for zones like Kesse-upstream seems a feasible option in order to cater for supplementary irrigation while indirectly tapping on subsurface water resources stored in the porous aquifers through basin interflows. Base flow data also showed that the discharge from upstream locations to the downstream exit of the watershed was high through direct surface river discharge and subsurface interflow. The temporal patterns of the hydrology indicate that annual paddy rice cultivation is ideal between May and October.
基金We thank Yanbin Cai for helping with the rice treatments. The work was supported by the National Natural Science Foundation of China （41103042）, the Field Frontier Project of Insti- tute of Geochemistry. Chinese Academy of Sciences （2045200295）. the Training Program for the Top Young Talents of Zhejiang Agri- cultural and Forestry University （2034070001）. and the Program for the Distinguished Young and middle-aged Academic Leaders of Higher Education Institutions of Zhejiang Province （PD2013240）.
文摘Global warming as a result of rapid increase in atmospheric COa emission is significantly influencing world＇s economy and human activities. Carbon sequestra- tion in phytoliths is regarded as a highly stable carbon sink mechanism in terrestrial ecosystems to mitigate climate change. However, the response of plant phytolith-occluded carbon （PhytOC） to external silicon amendments remains unclear. In this study, we investigated the effects of basalt powder （BP） amendment on phytolith carbon sequestration in rice （Oryza sativa）, a high-PhytOC accumulator. The results showed that the contents of phytolith and PhytOC in rice increased with BP amendment. The PhytOC produc- tion flux in different rice plant parts varied considerably （0.005-0.041 Mg CO_2 ha^-1 a^-1）, with the highest flux in the sheath. BP amendment can significantly enhance flux of phytolith carbon sequestration in croplands by 150 %. If the global rice cultivation of 1.55 × 10^8 ha had a similar flux of PhytOC production in this study, 0.61× 10^7 to 1.54 × 10^7 Mg CO_2 would be occluded annually within global rice phytoliths. These findings highlight that exter- nal silicon amendment such as BP amendment represents an effective potential management tool to increase long- term biogeochemical carbon sequestration in crops such as rice and may also be an efficient way to mitigate the global warming indirectly.
