To evaluate scientifically the change of photosynthetic and thermal potential productivity caused by climate variation,based on comparison with mean of previous 30 years(1971-2000),the change of total solar radiation,...To evaluate scientifically the change of photosynthetic and thermal potential productivity caused by climate variation,based on comparison with mean of previous 30 years(1971-2000),the change of total solar radiation,sunshine hours,photosynthetic active radiation,photosynthetic and thermal potential productivity since 2001 were analyzed through data of radiation,sunshine and temperature in Shandong Province from 1971 to 2007,and the change trend was also tested by Mann-Kendall non-parametric statistical met...展开更多
For some time, two major kinds of Total Factor Productivity (TFP) have existed independently of each other: the Solow residual and the Malmquist Productivity Index (MPI). The Solow residual was introduced in macr...For some time, two major kinds of Total Factor Productivity (TFP) have existed independently of each other: the Solow residual and the Malmquist Productivity Index (MPI). The Solow residual was introduced in macro economic growth models, and the MPI has been used in micro economics and management studies. As both indices were developed independently, few studies utilize both together and compare the results. This paper uses the same data to compare the two productivity indices by setting to determine the economic implications of combining the two indices. We discovered that we could decompose TFP with each aspect of the Soiow residual and MPI. We could then interpret their relationship in the business cycle. Our results indicated that the frontier shift in MPI of Japanese firms often occurred when the Solow residual increased, meaning that improving oroductivitv with the Solow residual could be generated by a firm that could shift new production frontiers.展开更多
Safflower represents an important oil crop internationally and may have a production potential under low input conditions, but its putatively high phosphorous use efficiency is not sustained. This study aims to direct...Safflower represents an important oil crop internationally and may have a production potential under low input conditions, but its putatively high phosphorous use efficiency is not sustained. This study aims to directly compare safflower with sunflower in terms of phosphorus use efficiency in nutrient solution under controlled conditions. Growth of both species responded strongly to increasing P supply. Safflower recovers less proportion of added P than sunflower. External P requirement ((g P supply (100 g dry matter (DM) produced)~) was higher in safflower than sunflower. The efficiency of the crops for DM production based on accumulated P (mg P potl, efficiency ratio), and P concentration in DM ((mg P (g DM)'I), utilization index) were interpreted using Michaelis-Menten kinetics as growth response curves. Accordingly, Km constant was lower in sunflower compared to safflower in terms of utilization index, but both were similar in terms of efficiency ratio. High Km constant in safflower in terms of utilization index indicates the high P concentration in tissues to produce 50% of potential maximum DM, consequently less efficient crop. Utilization efficiency contributed more than uptake efficiency in overall PUE in the efficient cultivar and could be the cause of its superiority in PUE. It can be concluded that safflower has a high requirement for P with respect to growth, sunflower is more efficient in terms of uptake and utilization of P at optimal and sub-optimal P supplies indicating that safflower can not be considered a low nutrient input crop compared to sunflower with respect to phosphorus.展开更多
Since 2003, the sites of the national environmental monitoring system (DNSE) of Niger, set up by the long term ecological monitoring observatories network (ROSELT) with the support of the Sahel and Sahara Observat...Since 2003, the sites of the national environmental monitoring system (DNSE) of Niger, set up by the long term ecological monitoring observatories network (ROSELT) with the support of the Sahel and Sahara Observatory (OSS), were used to collect ecological data with harmonized methods for spatio-temporal comparisons purpose. Floristic and phytoecological data were collected using the phytosociological methodology of Braun-Blanquet (1932). Ecosystem vital attributes used included the specific diversity, alpha diversity, equidistribution, biological types and herbaceous phytomass. At the whole system scale, the analysis revealed that the specific diversity, the alpha diversity and the phytomass values were higher in less disturbed biotopes of the north soudanian and south sahelian bioclimates where the rainfall rate is relatively high. Regarding the north sahelian and saharian bioclimates, the topography may play a critical role in the redistribution of this phytodiversity. Besides, the distribution of the biological types showed the prevalence of therophytes (56.8 ± 11%) regardless of the bioclimate and, to a lesser extent, the perennial species (26.5 ± 7.3%), the later group showing higher values for the north soudanian bioclimate.展开更多
Maize research at Institute for Agricultural Research, Samaru, Nigeria resulted in sustained growth in yields in the last two decades. Maize is grown throughout the country with guinea savanna as the most important ma...Maize research at Institute for Agricultural Research, Samaru, Nigeria resulted in sustained growth in yields in the last two decades. Maize is grown throughout the country with guinea savanna as the most important maize growing zone. In the last five years, four new open pollinating varieties developed in collaboration with the International Institute of Tropical Agriculture (IITA, Ibadan) had been released for production. Hybrid varieties are also marketed by seed companies. The research was focused on variety improvement, improved management practices, integrated pests and disease control, soil fertility management, on-farm testing of improved production packages and socio-economics of production as well as adoption studies. The recently released quality protein maize has improved the nutritional status of vulnerable groups. Drought tolerant maize for Africa research project has contributed to sustainable maize production, poverty reduction and food security in the continent.展开更多
Biological diversity involves genetic, species, and ecosystem diversity. Genetic diversity denotes the variation within species in the functional units of heredity present in any plant or animal, microbial or other or...Biological diversity involves genetic, species, and ecosystem diversity. Genetic diversity denotes the variation within species in the functional units of heredity present in any plant or animal, microbial or other origin of living things. Species diversity encompasses the variety of species--whether wild or domesticated, within a geographical area. This study assesses the economic value of crop productivity biodiversity in Ijebu Ode agricultural zone of Ogun State. The authors proposed a dynamic model of market equilibrium with vertical product differentiation that enabled us to take into account the economic consequences of respondents' monthly income and species crop of three different communities. The objectives of the study are to identify the personal and socio-economic characteristics of farmers and determine the importance of biodiversity in the study area using Simpson's Index. The result showed that 52.50% were male, majority (32.50%) were within the age range of 31 and 40 years old, 44.17% were married, 62.50% had household size of 6-10, and majority (45.83%) had secondary education while 46.67% had up to 20 years farming experience. In conclusion, the authors find that effective factors play an important role in explaining the support for biodiversity conservation, particularly when people do not have specific knowledge about species; while ecological-scientific considerations appear when people are well-informed.展开更多
The use of the power tillers (walking tractors) are increasingly popular in Nigeria among farmers adopting Sawah rice production technology. This study compares the effects of two types of power tillers on physical ...The use of the power tillers (walking tractors) are increasingly popular in Nigeria among farmers adopting Sawah rice production technology. This study compares the effects of two types of power tillers on physical properties of soil and rice yield. because soil properties determine to a large extents rice yield. Data on soil properties and rice yield were collected and subjected to t-test statistics. The results show that, significant differences exit for all the physical properties of soils rice yields from fields where the two power tiller were used with yields from rice field where SHAKTI was used was higher than KUBOTA. It is important that farmers using these models of power tillers for rice production should not only focus on the purchase cost of these power tillers but their overall efficiency in order to achieve the desired high level of yield.展开更多
Aims Variations in vegetation spring phenology are widely attributed to temperature in temperate and cold regions.However,temperature effect on phenology remains elusive in cold and arid/semiarid ecosystems because so...Aims Variations in vegetation spring phenology are widely attributed to temperature in temperate and cold regions.However,temperature effect on phenology remains elusive in cold and arid/semiarid ecosystems because soil water condition also plays an important role in mediating phenology.Methods We used growing degree day(GDD)model and growing season index(GSI)model,coupling minimum temperature(T_(min))with soil moisture(SM)to explore the influence of heat requirement and hydroclimatic interaction on the start of carbon uptake period(SCUP)and net ecosystem productivity(NEP)in two alpine meadows with different precipitation regimes on the Qinghai-Tibet Plateau(QTP).One is the water-limited alpine steppe-meadow,and the other is the temperature-limited alpine shrub-meadow.Important Findings We observed two clear patterns linking GDD and GSI to SCUP:SCUP was similarly sensitive to variations in preseason GDD and GSI in the humid alpine shrub-meadow,while SCUP was more sensitive to the variability in preseason GSI than GDD in the semiarid alpine steppe-meadow.The divergent patterns indicated a balance of the limiting climatic factors between temperature and water availability.In the humid meadow,higher temperature sensitivity of SCUP could maximize thermal benefit without drought stress,as evidenced by the stronger linear correlation coefficient(R2)and Akaike’s information criterion(AIC)between observed SCUPs and those of simulated by GDD model.However,greater water sensitivity of SCUP could maximize the benefit of water in semiarid steppe-meadow,which is indicated by the stronger R2 and AIC between observed SCUPs and those of simulated by GSI model.Additionally,although SCUPs were determined by GDD in the alpine shrub-meadow ecosystem,NEP was both controlled by accumulative GSI in two alpine meadows.Our study highlights the impacts of hydroclimatic interaction on spring carbon flux phenology and vegetation productivity in the humid and semiarid alpine ecosystems.The results also suggest that water,together with temperature should be included in the models of phenology and carbon budget for alpine ecosystems in semiarid regions.These fi ndings have important implications for improving vegetation phenology models,thus advancing our understanding of the interplay between vegetation phenology,productivity and climate change in future.展开更多
基金Supported by Special Project of China Meteorological Administrationon Effects of Climate Change on Solar Energy in East ChinaSpecial fund of Meteorological Science and Technology Services inShandong Province in 2006~~
文摘To evaluate scientifically the change of photosynthetic and thermal potential productivity caused by climate variation,based on comparison with mean of previous 30 years(1971-2000),the change of total solar radiation,sunshine hours,photosynthetic active radiation,photosynthetic and thermal potential productivity since 2001 were analyzed through data of radiation,sunshine and temperature in Shandong Province from 1971 to 2007,and the change trend was also tested by Mann-Kendall non-parametric statistical met...
文摘For some time, two major kinds of Total Factor Productivity (TFP) have existed independently of each other: the Solow residual and the Malmquist Productivity Index (MPI). The Solow residual was introduced in macro economic growth models, and the MPI has been used in micro economics and management studies. As both indices were developed independently, few studies utilize both together and compare the results. This paper uses the same data to compare the two productivity indices by setting to determine the economic implications of combining the two indices. We discovered that we could decompose TFP with each aspect of the Soiow residual and MPI. We could then interpret their relationship in the business cycle. Our results indicated that the frontier shift in MPI of Japanese firms often occurred when the Solow residual increased, meaning that improving oroductivitv with the Solow residual could be generated by a firm that could shift new production frontiers.
文摘Safflower represents an important oil crop internationally and may have a production potential under low input conditions, but its putatively high phosphorous use efficiency is not sustained. This study aims to directly compare safflower with sunflower in terms of phosphorus use efficiency in nutrient solution under controlled conditions. Growth of both species responded strongly to increasing P supply. Safflower recovers less proportion of added P than sunflower. External P requirement ((g P supply (100 g dry matter (DM) produced)~) was higher in safflower than sunflower. The efficiency of the crops for DM production based on accumulated P (mg P potl, efficiency ratio), and P concentration in DM ((mg P (g DM)'I), utilization index) were interpreted using Michaelis-Menten kinetics as growth response curves. Accordingly, Km constant was lower in sunflower compared to safflower in terms of utilization index, but both were similar in terms of efficiency ratio. High Km constant in safflower in terms of utilization index indicates the high P concentration in tissues to produce 50% of potential maximum DM, consequently less efficient crop. Utilization efficiency contributed more than uptake efficiency in overall PUE in the efficient cultivar and could be the cause of its superiority in PUE. It can be concluded that safflower has a high requirement for P with respect to growth, sunflower is more efficient in terms of uptake and utilization of P at optimal and sub-optimal P supplies indicating that safflower can not be considered a low nutrient input crop compared to sunflower with respect to phosphorus.
文摘Since 2003, the sites of the national environmental monitoring system (DNSE) of Niger, set up by the long term ecological monitoring observatories network (ROSELT) with the support of the Sahel and Sahara Observatory (OSS), were used to collect ecological data with harmonized methods for spatio-temporal comparisons purpose. Floristic and phytoecological data were collected using the phytosociological methodology of Braun-Blanquet (1932). Ecosystem vital attributes used included the specific diversity, alpha diversity, equidistribution, biological types and herbaceous phytomass. At the whole system scale, the analysis revealed that the specific diversity, the alpha diversity and the phytomass values were higher in less disturbed biotopes of the north soudanian and south sahelian bioclimates where the rainfall rate is relatively high. Regarding the north sahelian and saharian bioclimates, the topography may play a critical role in the redistribution of this phytodiversity. Besides, the distribution of the biological types showed the prevalence of therophytes (56.8 ± 11%) regardless of the bioclimate and, to a lesser extent, the perennial species (26.5 ± 7.3%), the later group showing higher values for the north soudanian bioclimate.
文摘Maize research at Institute for Agricultural Research, Samaru, Nigeria resulted in sustained growth in yields in the last two decades. Maize is grown throughout the country with guinea savanna as the most important maize growing zone. In the last five years, four new open pollinating varieties developed in collaboration with the International Institute of Tropical Agriculture (IITA, Ibadan) had been released for production. Hybrid varieties are also marketed by seed companies. The research was focused on variety improvement, improved management practices, integrated pests and disease control, soil fertility management, on-farm testing of improved production packages and socio-economics of production as well as adoption studies. The recently released quality protein maize has improved the nutritional status of vulnerable groups. Drought tolerant maize for Africa research project has contributed to sustainable maize production, poverty reduction and food security in the continent.
文摘Biological diversity involves genetic, species, and ecosystem diversity. Genetic diversity denotes the variation within species in the functional units of heredity present in any plant or animal, microbial or other origin of living things. Species diversity encompasses the variety of species--whether wild or domesticated, within a geographical area. This study assesses the economic value of crop productivity biodiversity in Ijebu Ode agricultural zone of Ogun State. The authors proposed a dynamic model of market equilibrium with vertical product differentiation that enabled us to take into account the economic consequences of respondents' monthly income and species crop of three different communities. The objectives of the study are to identify the personal and socio-economic characteristics of farmers and determine the importance of biodiversity in the study area using Simpson's Index. The result showed that 52.50% were male, majority (32.50%) were within the age range of 31 and 40 years old, 44.17% were married, 62.50% had household size of 6-10, and majority (45.83%) had secondary education while 46.67% had up to 20 years farming experience. In conclusion, the authors find that effective factors play an important role in explaining the support for biodiversity conservation, particularly when people do not have specific knowledge about species; while ecological-scientific considerations appear when people are well-informed.
文摘The use of the power tillers (walking tractors) are increasingly popular in Nigeria among farmers adopting Sawah rice production technology. This study compares the effects of two types of power tillers on physical properties of soil and rice yield. because soil properties determine to a large extents rice yield. Data on soil properties and rice yield were collected and subjected to t-test statistics. The results show that, significant differences exit for all the physical properties of soils rice yields from fields where the two power tiller were used with yields from rice field where SHAKTI was used was higher than KUBOTA. It is important that farmers using these models of power tillers for rice production should not only focus on the purchase cost of these power tillers but their overall efficiency in order to achieve the desired high level of yield.
基金supported by the National Natural Science Foundation of China(31870406,41661144045)the State Key Research and Development Program(2016YFC0502001,2017YFA0604801).
文摘Aims Variations in vegetation spring phenology are widely attributed to temperature in temperate and cold regions.However,temperature effect on phenology remains elusive in cold and arid/semiarid ecosystems because soil water condition also plays an important role in mediating phenology.Methods We used growing degree day(GDD)model and growing season index(GSI)model,coupling minimum temperature(T_(min))with soil moisture(SM)to explore the influence of heat requirement and hydroclimatic interaction on the start of carbon uptake period(SCUP)and net ecosystem productivity(NEP)in two alpine meadows with different precipitation regimes on the Qinghai-Tibet Plateau(QTP).One is the water-limited alpine steppe-meadow,and the other is the temperature-limited alpine shrub-meadow.Important Findings We observed two clear patterns linking GDD and GSI to SCUP:SCUP was similarly sensitive to variations in preseason GDD and GSI in the humid alpine shrub-meadow,while SCUP was more sensitive to the variability in preseason GSI than GDD in the semiarid alpine steppe-meadow.The divergent patterns indicated a balance of the limiting climatic factors between temperature and water availability.In the humid meadow,higher temperature sensitivity of SCUP could maximize thermal benefit without drought stress,as evidenced by the stronger linear correlation coefficient(R2)and Akaike’s information criterion(AIC)between observed SCUPs and those of simulated by GDD model.However,greater water sensitivity of SCUP could maximize the benefit of water in semiarid steppe-meadow,which is indicated by the stronger R2 and AIC between observed SCUPs and those of simulated by GSI model.Additionally,although SCUPs were determined by GDD in the alpine shrub-meadow ecosystem,NEP was both controlled by accumulative GSI in two alpine meadows.Our study highlights the impacts of hydroclimatic interaction on spring carbon flux phenology and vegetation productivity in the humid and semiarid alpine ecosystems.The results also suggest that water,together with temperature should be included in the models of phenology and carbon budget for alpine ecosystems in semiarid regions.These fi ndings have important implications for improving vegetation phenology models,thus advancing our understanding of the interplay between vegetation phenology,productivity and climate change in future.