Effects of the extracts of muhly grass （Muhlenbergia capillaries Lam.）, chenopodium （Chenopodium ambrosioides L.） and black walnut （Juglans nigra L.） on the growth of cogongrass （Imperata cylindrica L.） were s...Effects of the extracts of muhly grass （Muhlenbergia capillaries Lam.）, chenopodium （Chenopodium ambrosioides L.） and black walnut （Juglans nigra L.） on the growth of cogongrass （Imperata cylindrica L.） were studied. None purified extracts from these plant species were used to evaluate survival, shoot and root growth of cogongrass. Results of plant species extracts on the production of roots, shoot and rhizomes of cogongrass genets and ramets were determined on a weekly basis. The extracts significantly reduced the growth and survival of cogongrass when compared to the control. Results indicated that for the in vivo studies, chenopodium extracts, black walnut and muhly grass extracts reduced growth, root and shoot biomass of cogongrass by 50 %, 30 % and 41% respectively, compared to control at 8 weeks after planting. These studies indicated plant species with potential for the biological control of cogongrass, an invasive species in the Gulf Coast States.展开更多
Soil erosion is among the critical environmental constraint for crop production in southern Mali. Contour ridge tillage (CRT), a water conservation technique had been locally applied since 1990. The objective of this ...Soil erosion is among the critical environmental constraint for crop production in southern Mali. Contour ridge tillage (CRT), a water conservation technique had been locally applied since 1990. The objective of this study was to determine the effects of CRT compared with farmer conventional agriculture practice (NoCRT) on runoff, soil loss, nutrient loss, moisture conservation and cereals yields under rainfed conditions in two Southern Mali sites, in 2016 and 2017 in farmer fields. Measurements were performed on erosion plots composed of CRT and NoCRT plots from which water samples were collected to determine sedimentation levels, concentration and nutrients losses using pairwise comparison. Average runoff coefficient in NoCRT plots was 35.62% compared to 19.25% for the CRT plots explaining a runoff reduction of 46%. Mean soil losses of 12,095 t·ha-1 and 4970 t·ha-1 were respectively measured in NoCRT and CRT plots. Losses in calcium, magnesium and potassium nutrients in the NoCRT plots were 80%, 66%, 75% higher compared to CRT ones, respectively. Sorghum grain yield was at least two folds higher in CRT plots compared to the NoCRT plots. Maize average grain yield was 87% higher in CRT plots than in the NoCRT. For sustained soil productivity, CRT is advocated as a better soil and water management technique than the NoCRT one.展开更多
Agricultural production is highly dependent on the climatic variability of the specific regions. Differential climatic and soil conditions bring about changes in yield, quality of crops thus affecting the economy. Thi...Agricultural production is highly dependent on the climatic variability of the specific regions. Differential climatic and soil conditions bring about changes in yield, quality of crops thus affecting the economy. This study evaluated the impact of variability in different climatic factors keeping the other factors constant on spring wheat production in North Dakota from 2007 to 2011. The spring wheat yield mainly depends on the climatic changes during growing periods April to September. Average maximum air temperature was significantly different from April to September except June from 2007 to 2011. High average minimum and maximum air temperatures during planting time increase yield and planting area for 2010. In 2011, low mean soil temperature, excess rainfall in April caused low yield of spring wheat. The unmitigated climate variability will result in declines in yields. So, adoption of sustainable agriculture practices helps the farmers to develop the different practices for their farms.展开更多
Background:Many fire-dependent forests have experienced significant declines in species,structural,and functional diversity.These changes are attributed in part to traditional management approaches that were dominated...Background:Many fire-dependent forests have experienced significant declines in species,structural,and functional diversity.These changes are attributed in part to traditional management approaches that were dominated by even-aged regeneration methods such as clearcutting.Variable retention harvesting(VRH)is an ecologically based forestry practice that involves retention of some mature overstory trees and other biological structures in the postharvest stand to emulate the effects of natural disturbance events.In this study,we examined the effect of a VRH treatment on recruitment of historically dominant pine species and understory vegetation twoand six years after its implementation in a naturally regenerated mixed pine forest in the Upper Peninsula of Michigan,USA.Results:We found greater regeneration of red pine(Pinus resinosa L.)and eastern white pine(Pinus strobus L.)in VRH stands compared to the unharvested controls.Although red pine recruitment was very low during the first 2 years,both species increased significantly from year two to year six.Recruitment responses for the two species did not differ significantly between the aggregated and dispersed retention treatments.We also found high recruitment of deciduous tree species,consisting primarily of sprouts,and red pine exhibited a negative correlation with these sprouts.Treatment,time,and the interaction of treatment and time were significant factors in red pine recruitment.Time had a strong effect on the understory vegetation,with significant decreases in shrubs and ferns over time.Conclusions:The results suggest that VRH enhanced recruitment of red pine and eastern white pine and that this recruitment increased with time.We identify competition from sprouts and unfavorable seedbed conditions as the main factors that limited recruitment of red pine during the first 2 years.To reduce competing vegetation and improve seedbed conditions,we suggest following the VRH with a prescribed fire,mechanically removing sprouts,and implementing herbicide treatments.At a time when changes in global climate exacerbates the effects of traditional drivers of forest degradation,and with the need to maintain biodiversity,new ecologically based forest practices such VRH have the potential to facilitate regeneration of native trees and enhance the resilience of many fire-dependent forests.展开更多
The Pan-Eurasian Experiment Modelling Platform(PEEX-MP)is one of the key blocks of the PEEX Research Programme.The PEEX MP has more than 30 models and is directed towards seamless envir-onmental prediction.The main fo...The Pan-Eurasian Experiment Modelling Platform(PEEX-MP)is one of the key blocks of the PEEX Research Programme.The PEEX MP has more than 30 models and is directed towards seamless envir-onmental prediction.The main focus area is the Arctic-boreal regions and China.The models used in PEEX-MP cover several main components of the Earth’s system,such as the atmosphere,hydrosphere,pedosphere and biosphere,and resolve the physicalchemicalbiological processes at different spatial and temporal scales and resolutions.This paper introduces and discusses PEEX MP multi-scale modelling concept for the Earth system,online integrated,forward/inverse,and socioeconomical modelling,and other approaches with a particular focus on applications in the PEEX geographical domain.The employed high-performance com-puting facilities,capabilities,and PEEX dataflow for modelling results are described.Several virtual research platforms(PEEXView,Virtual Research Environment,Web-based Atlas)for handling PEEX modelling and observational results are introduced.The over-all approach allows us to understand better physical-chemicalbiological processes,Earth’s system interactions and feedbacks and to provide valuable information for assessment studies on evaluating risks,impact,consequences,etc.for population,envir-onment and climate in the PEEX domain.This work was also one of the last projects of Prof.Sergej Zilitinkevich,who passed away on 15 February 2021.Since the finalization took time,the paper was actually submitted in 2023 and we could not argue that the final paper text was agreed with him.展开更多
Mammals can show conspicuous behavioral responses to thermal variation,including changes in movement patterns.We used an integrative approach to understand how environmental temperature can drive the movement behavior...Mammals can show conspicuous behavioral responses to thermal variation,including changes in movement patterns.We used an integrative approach to understand how environmental temperature can drive the movement behavior of a mammal with low capacity for physiological thermoregulation,the giant anteater(Myrmecophaga tridactyla).We tracked 52 giant anteaters in 7 areas throughout the Brazilian savannah.We estimated the distance moved,area used,use of forest areas,and mean environmental temperature for each monitoring day of each individual.We modeled these data with Mixed Structural Equations—considering the possible interactions between our variables and controlling for sex and body mass.Giant anteaters reduced displacement and increased forest use with decreasing environmental temperature,probably because of their low body heat production.It is possible that they reduce distance moved and area used by reducing the duration of activity.With decreasing temperature,forest habitats become warmer than open ones,besides buffer rain and chilly winds.Reducing displacement and using forests are important strategies to reduce body heat loss and the energetic costs of thermoregulation.However,decreasing movement can limit food access and,consequently,fitness.Therefore,we highlight the importance of forests as thermal shelters.With increasing frequency and intensity of extreme weather events,we showed the need to preserve forest patches to offer suitable conditions for tropical mammals’behavioral thermoregulation.In this context,policies favoring deforestation on Brazilian territory are especially worrisome.Finally,we emphasize the need of integrative approaches to understand the complex interactions between organisms and the environment.展开更多
文摘Effects of the extracts of muhly grass （Muhlenbergia capillaries Lam.）, chenopodium （Chenopodium ambrosioides L.） and black walnut （Juglans nigra L.） on the growth of cogongrass （Imperata cylindrica L.） were studied. None purified extracts from these plant species were used to evaluate survival, shoot and root growth of cogongrass. Results of plant species extracts on the production of roots, shoot and rhizomes of cogongrass genets and ramets were determined on a weekly basis. The extracts significantly reduced the growth and survival of cogongrass when compared to the control. Results indicated that for the in vivo studies, chenopodium extracts, black walnut and muhly grass extracts reduced growth, root and shoot biomass of cogongrass by 50 %, 30 % and 41% respectively, compared to control at 8 weeks after planting. These studies indicated plant species with potential for the biological control of cogongrass, an invasive species in the Gulf Coast States.
文摘Soil erosion is among the critical environmental constraint for crop production in southern Mali. Contour ridge tillage (CRT), a water conservation technique had been locally applied since 1990. The objective of this study was to determine the effects of CRT compared with farmer conventional agriculture practice (NoCRT) on runoff, soil loss, nutrient loss, moisture conservation and cereals yields under rainfed conditions in two Southern Mali sites, in 2016 and 2017 in farmer fields. Measurements were performed on erosion plots composed of CRT and NoCRT plots from which water samples were collected to determine sedimentation levels, concentration and nutrients losses using pairwise comparison. Average runoff coefficient in NoCRT plots was 35.62% compared to 19.25% for the CRT plots explaining a runoff reduction of 46%. Mean soil losses of 12,095 t·ha-1 and 4970 t·ha-1 were respectively measured in NoCRT and CRT plots. Losses in calcium, magnesium and potassium nutrients in the NoCRT plots were 80%, 66%, 75% higher compared to CRT ones, respectively. Sorghum grain yield was at least two folds higher in CRT plots compared to the NoCRT plots. Maize average grain yield was 87% higher in CRT plots than in the NoCRT. For sustained soil productivity, CRT is advocated as a better soil and water management technique than the NoCRT one.
文摘Agricultural production is highly dependent on the climatic variability of the specific regions. Differential climatic and soil conditions bring about changes in yield, quality of crops thus affecting the economy. This study evaluated the impact of variability in different climatic factors keeping the other factors constant on spring wheat production in North Dakota from 2007 to 2011. The spring wheat yield mainly depends on the climatic changes during growing periods April to September. Average maximum air temperature was significantly different from April to September except June from 2007 to 2011. High average minimum and maximum air temperatures during planting time increase yield and planting area for 2010. In 2011, low mean soil temperature, excess rainfall in April caused low yield of spring wheat. The unmitigated climate variability will result in declines in yields. So, adoption of sustainable agriculture practices helps the farmers to develop the different practices for their farms.
基金the Joint Fire Science Program(JFSP),The Ohio State University,Seney National Wildlife Refuge(SNWR)Seney Natural History Association.
文摘Background:Many fire-dependent forests have experienced significant declines in species,structural,and functional diversity.These changes are attributed in part to traditional management approaches that were dominated by even-aged regeneration methods such as clearcutting.Variable retention harvesting(VRH)is an ecologically based forestry practice that involves retention of some mature overstory trees and other biological structures in the postharvest stand to emulate the effects of natural disturbance events.In this study,we examined the effect of a VRH treatment on recruitment of historically dominant pine species and understory vegetation twoand six years after its implementation in a naturally regenerated mixed pine forest in the Upper Peninsula of Michigan,USA.Results:We found greater regeneration of red pine(Pinus resinosa L.)and eastern white pine(Pinus strobus L.)in VRH stands compared to the unharvested controls.Although red pine recruitment was very low during the first 2 years,both species increased significantly from year two to year six.Recruitment responses for the two species did not differ significantly between the aggregated and dispersed retention treatments.We also found high recruitment of deciduous tree species,consisting primarily of sprouts,and red pine exhibited a negative correlation with these sprouts.Treatment,time,and the interaction of treatment and time were significant factors in red pine recruitment.Time had a strong effect on the understory vegetation,with significant decreases in shrubs and ferns over time.Conclusions:The results suggest that VRH enhanced recruitment of red pine and eastern white pine and that this recruitment increased with time.We identify competition from sprouts and unfavorable seedbed conditions as the main factors that limited recruitment of red pine during the first 2 years.To reduce competing vegetation and improve seedbed conditions,we suggest following the VRH with a prescribed fire,mechanically removing sprouts,and implementing herbicide treatments.At a time when changes in global climate exacerbates the effects of traditional drivers of forest degradation,and with the need to maintain biodiversity,new ecologically based forest practices such VRH have the potential to facilitate regeneration of native trees and enhance the resilience of many fire-dependent forests.
基金the last projects of Prof.Sergej Zilitinkevich(1936-2021)The financial support was/is provided through multiple projects related to the Pan-Eurasian EXperiment(PEEX)programme including Academy of Finland projects-ClimEco(grant#314798/799)+6 种基金ACCC(grant#337549)HEATCOST(grant#334798)European Union’s Horizon 2020 Programme projects-iCUPE under ERA-PLANET(grant#689443),INTAROS(grant#727890),EXHAUSTION(grant#820655),CRiceS(grant#101003826),RI-URBANS(grant#101036245)Horizon Europe project FOCI(grant#101056783)Erasmus+Programme projects-ECOIMPACT(grant#561975-EPP-1-2015-1-FI-EPPKA2-CBHE-JP),ClimEd(grant#619285-EPP-1-2020-1-FIEPPKA2-CBHE-JP)The Norwegian Research Council INTPART educational and networking project(322317/H30):URban Sustainability in Action:Multi-disciplinary Approach through Jointly Organized Research schoolsand the EEA project(Contract No.2020TO01000219):Turbulent-resolving urban modelling of air quality and thermal comfort(TURBAN).
文摘The Pan-Eurasian Experiment Modelling Platform(PEEX-MP)is one of the key blocks of the PEEX Research Programme.The PEEX MP has more than 30 models and is directed towards seamless envir-onmental prediction.The main focus area is the Arctic-boreal regions and China.The models used in PEEX-MP cover several main components of the Earth’s system,such as the atmosphere,hydrosphere,pedosphere and biosphere,and resolve the physicalchemicalbiological processes at different spatial and temporal scales and resolutions.This paper introduces and discusses PEEX MP multi-scale modelling concept for the Earth system,online integrated,forward/inverse,and socioeconomical modelling,and other approaches with a particular focus on applications in the PEEX geographical domain.The employed high-performance com-puting facilities,capabilities,and PEEX dataflow for modelling results are described.Several virtual research platforms(PEEXView,Virtual Research Environment,Web-based Atlas)for handling PEEX modelling and observational results are introduced.The over-all approach allows us to understand better physical-chemicalbiological processes,Earth’s system interactions and feedbacks and to provide valuable information for assessment studies on evaluating risks,impact,consequences,etc.for population,envir-onment and climate in the PEEX domain.This work was also one of the last projects of Prof.Sergej Zilitinkevich,who passed away on 15 February 2021.Since the finalization took time,the paper was actually submitted in 2023 and we could not argue that the final paper text was agreed with him.
基金This work was supported by the Brasilian Conselho Nacional de Desenvolvimento Científico e Tecnológico-CNPQ(133623/2017-3 to AG and 308934/2017-2 to GM)National Program of post doctorate of Coordenação de Aperfeiçoamento de Pessoal de Nível Superior-CAPES(PNPD 1694744 to ZO)São Paulo Research Foundation-FAPESP(2013/18526-9 and 2013/04957-8 to AB).
文摘Mammals can show conspicuous behavioral responses to thermal variation,including changes in movement patterns.We used an integrative approach to understand how environmental temperature can drive the movement behavior of a mammal with low capacity for physiological thermoregulation,the giant anteater(Myrmecophaga tridactyla).We tracked 52 giant anteaters in 7 areas throughout the Brazilian savannah.We estimated the distance moved,area used,use of forest areas,and mean environmental temperature for each monitoring day of each individual.We modeled these data with Mixed Structural Equations—considering the possible interactions between our variables and controlling for sex and body mass.Giant anteaters reduced displacement and increased forest use with decreasing environmental temperature,probably because of their low body heat production.It is possible that they reduce distance moved and area used by reducing the duration of activity.With decreasing temperature,forest habitats become warmer than open ones,besides buffer rain and chilly winds.Reducing displacement and using forests are important strategies to reduce body heat loss and the energetic costs of thermoregulation.However,decreasing movement can limit food access and,consequently,fitness.Therefore,we highlight the importance of forests as thermal shelters.With increasing frequency and intensity of extreme weather events,we showed the need to preserve forest patches to offer suitable conditions for tropical mammals’behavioral thermoregulation.In this context,policies favoring deforestation on Brazilian territory are especially worrisome.Finally,we emphasize the need of integrative approaches to understand the complex interactions between organisms and the environment.
