The Experts below are selected from a list of 18732 Experts worldwide ranked by ideXlab platform
Kelin Wang - One of the best experts on this subject based on the ideXlab platform.
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responses of soil microbial Resource Limitation to multiple fertilization strategies
Soil & Tillage Research, 2020Co-Authors: Liang Zheng, Hao Chen, Kongcao Xiao, Kelin Wang, Yunqiu Wang, Mianhai Zheng, Yirong Su, Dejun LiAbstract:Abstract Fertilization is a key management practice for maintaining or improving soil fertility in agro-ecosystems. Nevertheless, how fertilization strategies impact the status of soil microbial Resource Limitation is poorly understood. Here, we investigated the effects of long-term (11 years) fertilization on microbial Resource Limitation in a karst cropland under maize–soybean rotation. Soil microbial Resource Limitation was assessed using enzymatic stoichiometry. Six fertilization strategies were included, i.e., i) no fertilization (control), ii) inorganic fertilizers only (NPK), iii) inorganic fertilizers plus a low amount of straw (LSNPK), iv) inorganic fertilizers plus a low amount of manure (LMNPK), v) inorganic fertilizers plus a high amount of straw (HSNPK), and vi) inorganic fertilizers plus a high amount of manure (HMNPK). Overall, soil microbes were not limited by nitrogen, but co-limited by carbon and phosphorus across the six fertilization strategies. However, the degrees of microbial Resource Limitations were different between the control and fertilizer treatments. Application with inorganic fertilizers only aggravated microbial carbon Limitation, but combined application of inorganic fertilizers and organic matters did not change the status of carbon Limitation relative to the control. None of the fertilizer treatments changed the status of microbial nitrogen Limitation. The treatments of NPK, LSNPK and LMNPK alleviated microbial phosphorus Limitation, but HSNPK and HMNPK had no significant effects on phosphorus Limitation relative to the control. By contrast, the crop production had no significant difference among all fertilizer treatments in the current study. Together, our results indicate that fertilizations can change microbial Resource Limitation status, which might be a more sensitive indicator to identify effective fertilization strategies relative to the crop production. Here we suggest that karst croplands do not need too much nitrogen fertilizer due to the nitrogen-rich characteristic, and that combined inorganic and organic fertilization strategies are better than single fertilization strategy in karst croplands.
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cropland conversion changes the status of microbial Resource Limitation in degraded karst soil
Geoderma, 2019Co-Authors: Hao Chen, Kongcao Xiao, Kelin Wang, Mianhai Zheng, Dejun LiAbstract:Abstract Cropland conversion has been suggested as a major strategy to improve the fertility of degraded croplands, but whether cropland conversion changes the status of microbial Resource Limitation remains poorly understood. Here, we studied three common cropland conversion strategies in a karst area of southwest China (i.e., conversion with i) Toona sinensis (TS), ii) Guimu-1 hybrid elephant grass (GG), and iii) a combination of Zenia insignis and Guimu-1 hybrid elephant grass (ZG) using cropland (CR) with maize-soybean rotation as reference. Enzymatic stoichiometry was calculated and used as an indicator of microbial Resource Limitation. Soil enzyme activity was altered after cropland conversions, which was strongly related to changes in soil properties. Enzymatic stoichiometry further showed that microbial carbon (C) Limitation was mitigated under all three conversion strategies, but nitrogen (N) and phosphorus (P) Limitations were aggravated under TS and GG. The mitigated Limitation of microbial C may be due to the elevated soil C content, and the aggravated microbial N and P Limitation may have been due to increased soil C/N and C/P, respectively. This study suggests that cropland conversion can change microbial Resource Limitation, which should be considered in the assessment and management of rebuilding ecosystems after cropland conversions.
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Resource Limitation of soil microbes in karst ecosystems
Science of The Total Environment, 2019Co-Authors: Hao Chen, Dejun Li, Kongcao Xiao, Kelin WangAbstract:Abstract Knowledge about Resource Limitation to soil microbes is crucial for understanding ecosystem functions and processes, and for predicting ecosystem responses to global changes as well. Karst ecosystems are widespread in the world, and play a key role in regulating the global climate, however, the patterns of and mechanisms underlying microbial Resource Limitation in karst ecosystems remain poorly known. Here we investigated the microbial Resource Limitation in a karst region, by selecting four main land-use types, i.e. cropland, grassland, shrubland and secondary forest, in areas underlain by two lithology types, i.e. dolomite and limestone, in southwest China. Ecoenzymatic stoichiometry was used as an indicator of microbial Resource Limitation. Overall, soil microbes in karst ecosystems were more limited by carbon and phosphorus, rather than by nitrogen. Further analyses revealed that the patterns of carbon and phosphorus Limitation were different among land-use or lithology types. Microbial carbon Limitation was greatest in cropland and forest but lowest in grassland, and was greater under dolomite than under limestone. Microbial phosphorus Limitation decreased from secondary forest to cropland under dolomite areas, but showed no difference among ecosystem types under limestone areas, indicating that lithology controls the pattern of microbial phosphorus Limitation along the post-agriculture succession. Our study describes a general pattern of microbial Resource Limitation in karst ecosystems, and we suggest that lithology may provide a new mechanism for explaining the variations of microbial Resource Limitation along the post-agriculture succession in different regions.
Dejun Li - One of the best experts on this subject based on the ideXlab platform.
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responses of soil microbial Resource Limitation to multiple fertilization strategies
Soil & Tillage Research, 2020Co-Authors: Liang Zheng, Hao Chen, Kongcao Xiao, Kelin Wang, Yunqiu Wang, Mianhai Zheng, Yirong Su, Dejun LiAbstract:Abstract Fertilization is a key management practice for maintaining or improving soil fertility in agro-ecosystems. Nevertheless, how fertilization strategies impact the status of soil microbial Resource Limitation is poorly understood. Here, we investigated the effects of long-term (11 years) fertilization on microbial Resource Limitation in a karst cropland under maize–soybean rotation. Soil microbial Resource Limitation was assessed using enzymatic stoichiometry. Six fertilization strategies were included, i.e., i) no fertilization (control), ii) inorganic fertilizers only (NPK), iii) inorganic fertilizers plus a low amount of straw (LSNPK), iv) inorganic fertilizers plus a low amount of manure (LMNPK), v) inorganic fertilizers plus a high amount of straw (HSNPK), and vi) inorganic fertilizers plus a high amount of manure (HMNPK). Overall, soil microbes were not limited by nitrogen, but co-limited by carbon and phosphorus across the six fertilization strategies. However, the degrees of microbial Resource Limitations were different between the control and fertilizer treatments. Application with inorganic fertilizers only aggravated microbial carbon Limitation, but combined application of inorganic fertilizers and organic matters did not change the status of carbon Limitation relative to the control. None of the fertilizer treatments changed the status of microbial nitrogen Limitation. The treatments of NPK, LSNPK and LMNPK alleviated microbial phosphorus Limitation, but HSNPK and HMNPK had no significant effects on phosphorus Limitation relative to the control. By contrast, the crop production had no significant difference among all fertilizer treatments in the current study. Together, our results indicate that fertilizations can change microbial Resource Limitation status, which might be a more sensitive indicator to identify effective fertilization strategies relative to the crop production. Here we suggest that karst croplands do not need too much nitrogen fertilizer due to the nitrogen-rich characteristic, and that combined inorganic and organic fertilization strategies are better than single fertilization strategy in karst croplands.
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cropland conversion changes the status of microbial Resource Limitation in degraded karst soil
Geoderma, 2019Co-Authors: Hao Chen, Kongcao Xiao, Kelin Wang, Mianhai Zheng, Dejun LiAbstract:Abstract Cropland conversion has been suggested as a major strategy to improve the fertility of degraded croplands, but whether cropland conversion changes the status of microbial Resource Limitation remains poorly understood. Here, we studied three common cropland conversion strategies in a karst area of southwest China (i.e., conversion with i) Toona sinensis (TS), ii) Guimu-1 hybrid elephant grass (GG), and iii) a combination of Zenia insignis and Guimu-1 hybrid elephant grass (ZG) using cropland (CR) with maize-soybean rotation as reference. Enzymatic stoichiometry was calculated and used as an indicator of microbial Resource Limitation. Soil enzyme activity was altered after cropland conversions, which was strongly related to changes in soil properties. Enzymatic stoichiometry further showed that microbial carbon (C) Limitation was mitigated under all three conversion strategies, but nitrogen (N) and phosphorus (P) Limitations were aggravated under TS and GG. The mitigated Limitation of microbial C may be due to the elevated soil C content, and the aggravated microbial N and P Limitation may have been due to increased soil C/N and C/P, respectively. This study suggests that cropland conversion can change microbial Resource Limitation, which should be considered in the assessment and management of rebuilding ecosystems after cropland conversions.
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Resource Limitation of soil microbes in karst ecosystems
Science of The Total Environment, 2019Co-Authors: Hao Chen, Dejun Li, Kongcao Xiao, Kelin WangAbstract:Abstract Knowledge about Resource Limitation to soil microbes is crucial for understanding ecosystem functions and processes, and for predicting ecosystem responses to global changes as well. Karst ecosystems are widespread in the world, and play a key role in regulating the global climate, however, the patterns of and mechanisms underlying microbial Resource Limitation in karst ecosystems remain poorly known. Here we investigated the microbial Resource Limitation in a karst region, by selecting four main land-use types, i.e. cropland, grassland, shrubland and secondary forest, in areas underlain by two lithology types, i.e. dolomite and limestone, in southwest China. Ecoenzymatic stoichiometry was used as an indicator of microbial Resource Limitation. Overall, soil microbes in karst ecosystems were more limited by carbon and phosphorus, rather than by nitrogen. Further analyses revealed that the patterns of carbon and phosphorus Limitation were different among land-use or lithology types. Microbial carbon Limitation was greatest in cropland and forest but lowest in grassland, and was greater under dolomite than under limestone. Microbial phosphorus Limitation decreased from secondary forest to cropland under dolomite areas, but showed no difference among ecosystem types under limestone areas, indicating that lithology controls the pattern of microbial phosphorus Limitation along the post-agriculture succession. Our study describes a general pattern of microbial Resource Limitation in karst ecosystems, and we suggest that lithology may provide a new mechanism for explaining the variations of microbial Resource Limitation along the post-agriculture succession in different regions.
Michael S. Mitchell - One of the best experts on this subject based on the ideXlab platform.
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Evaluating intercepts from demographic models to understand Resource Limitation and Resource thresholds
Ecological Modelling, 2008Co-Authors: Melissa J. Reynolds-hogland, John S. Hogland, Michael S. MitchellAbstract:Understanding Resource Limitation is critical to effective management and conservation of wild populations, however Resource Limitation is difficult to quantify partly because Resource Limitation is a dynamic process. Specifically, a Resource that is limiting at one time may become non-limiting at another time, depending upon changes in its availability and changes in the availability of other Resources. Methods for understanding Resource Limitation, therefore, must consider the dynamic effects of Resources on demography. We present approaches for interpreting results of demographic modeling beyond analyzing model rankings, model weights, slope estimates, and model averaging. We demonstrate how interpretation of y-intercepts, odds ratios, and rates of change can yield insights into Resource Limitation as a dynamic process, assuming logistic regression is used to link estimates of Resources with estimates of demography. In addition, we show how x-intercepts can be evaluated with respect to odds ratios to understand Resource thresholds.
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linking Resources with demography to understand Resource Limitation for bears
Journal of Applied Ecology, 2007Co-Authors: Melissa J Reynoldshogland, Lara B Pacifici, Michael S. MitchellAbstract:Summary 1 Identifying the Resources that limit growth of animal populations is essential for effective conservation; however, Resource Limitation is difficult to quantify. Recent advances in geographical information systems (GIS) and Resource modelling can be combined with demographic modelling to yield insights into Resource Limitation. 2 Using long-term data on a population of black bears Ursus americanus, we evaluated competing hypotheses about whether availability of hard mast (acorns and nuts) or soft mast (fleshy fruits) limited bears in the southern Appalachians, USA, during 1981–2002. The effects of clearcutting on habitat quality were also evaluated. Annual survival, recruitment and population growth rate were estimated using capture–recapture data from 101 females. The availability of hard mast, soft mast and clearcuts was estimated with a GIS, as each changed through time as a result of harvest and succession, and then availabilities were incorporated as covariates for each demographic parameter. 3 The model with the additive availability of hard mast and soft mast across the landscape predicted survival and population growth rate. Availability of young clearcuts predicted recruitment, but not population growth or survival. 4 Availability of hard mast stands across the landscape and availability of soft mast across the landscape were more important than hard mast production and availability of soft mast in young clearcuts, respectively. 5 Synthesis and applications. Our results indicate that older stands, which support high levels of hard mast and moderate levels of soft mast, should be maintained to sustain population growth of bears in the southern Appalachians. Simultaneously, the acreage of intermediate aged stands (10–25 years), which support very low levels of both hard mast and soft mast, should be minimized. The approach used in this study has broad application for wildlife management and conservation. State and federal wildlife agencies often possess long-term data on both Resource availability and capture–recapture for wild populations. Combined, these two data types can be used to estimate survival, recruitment, population growth, elasticities of vital rates and the effects of Resource availability on demographic parameters. Hence data that are traditionally used to understand population trends can be used to evaluate how and why demography changes over time.
Hao Chen - One of the best experts on this subject based on the ideXlab platform.
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responses of soil microbial Resource Limitation to multiple fertilization strategies
Soil & Tillage Research, 2020Co-Authors: Liang Zheng, Hao Chen, Kongcao Xiao, Kelin Wang, Yunqiu Wang, Mianhai Zheng, Yirong Su, Dejun LiAbstract:Abstract Fertilization is a key management practice for maintaining or improving soil fertility in agro-ecosystems. Nevertheless, how fertilization strategies impact the status of soil microbial Resource Limitation is poorly understood. Here, we investigated the effects of long-term (11 years) fertilization on microbial Resource Limitation in a karst cropland under maize–soybean rotation. Soil microbial Resource Limitation was assessed using enzymatic stoichiometry. Six fertilization strategies were included, i.e., i) no fertilization (control), ii) inorganic fertilizers only (NPK), iii) inorganic fertilizers plus a low amount of straw (LSNPK), iv) inorganic fertilizers plus a low amount of manure (LMNPK), v) inorganic fertilizers plus a high amount of straw (HSNPK), and vi) inorganic fertilizers plus a high amount of manure (HMNPK). Overall, soil microbes were not limited by nitrogen, but co-limited by carbon and phosphorus across the six fertilization strategies. However, the degrees of microbial Resource Limitations were different between the control and fertilizer treatments. Application with inorganic fertilizers only aggravated microbial carbon Limitation, but combined application of inorganic fertilizers and organic matters did not change the status of carbon Limitation relative to the control. None of the fertilizer treatments changed the status of microbial nitrogen Limitation. The treatments of NPK, LSNPK and LMNPK alleviated microbial phosphorus Limitation, but HSNPK and HMNPK had no significant effects on phosphorus Limitation relative to the control. By contrast, the crop production had no significant difference among all fertilizer treatments in the current study. Together, our results indicate that fertilizations can change microbial Resource Limitation status, which might be a more sensitive indicator to identify effective fertilization strategies relative to the crop production. Here we suggest that karst croplands do not need too much nitrogen fertilizer due to the nitrogen-rich characteristic, and that combined inorganic and organic fertilization strategies are better than single fertilization strategy in karst croplands.
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cropland conversion changes the status of microbial Resource Limitation in degraded karst soil
Geoderma, 2019Co-Authors: Hao Chen, Kongcao Xiao, Kelin Wang, Mianhai Zheng, Dejun LiAbstract:Abstract Cropland conversion has been suggested as a major strategy to improve the fertility of degraded croplands, but whether cropland conversion changes the status of microbial Resource Limitation remains poorly understood. Here, we studied three common cropland conversion strategies in a karst area of southwest China (i.e., conversion with i) Toona sinensis (TS), ii) Guimu-1 hybrid elephant grass (GG), and iii) a combination of Zenia insignis and Guimu-1 hybrid elephant grass (ZG) using cropland (CR) with maize-soybean rotation as reference. Enzymatic stoichiometry was calculated and used as an indicator of microbial Resource Limitation. Soil enzyme activity was altered after cropland conversions, which was strongly related to changes in soil properties. Enzymatic stoichiometry further showed that microbial carbon (C) Limitation was mitigated under all three conversion strategies, but nitrogen (N) and phosphorus (P) Limitations were aggravated under TS and GG. The mitigated Limitation of microbial C may be due to the elevated soil C content, and the aggravated microbial N and P Limitation may have been due to increased soil C/N and C/P, respectively. This study suggests that cropland conversion can change microbial Resource Limitation, which should be considered in the assessment and management of rebuilding ecosystems after cropland conversions.
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Resource Limitation of soil microbes in karst ecosystems
Science of The Total Environment, 2019Co-Authors: Hao Chen, Dejun Li, Kongcao Xiao, Kelin WangAbstract:Abstract Knowledge about Resource Limitation to soil microbes is crucial for understanding ecosystem functions and processes, and for predicting ecosystem responses to global changes as well. Karst ecosystems are widespread in the world, and play a key role in regulating the global climate, however, the patterns of and mechanisms underlying microbial Resource Limitation in karst ecosystems remain poorly known. Here we investigated the microbial Resource Limitation in a karst region, by selecting four main land-use types, i.e. cropland, grassland, shrubland and secondary forest, in areas underlain by two lithology types, i.e. dolomite and limestone, in southwest China. Ecoenzymatic stoichiometry was used as an indicator of microbial Resource Limitation. Overall, soil microbes in karst ecosystems were more limited by carbon and phosphorus, rather than by nitrogen. Further analyses revealed that the patterns of carbon and phosphorus Limitation were different among land-use or lithology types. Microbial carbon Limitation was greatest in cropland and forest but lowest in grassland, and was greater under dolomite than under limestone. Microbial phosphorus Limitation decreased from secondary forest to cropland under dolomite areas, but showed no difference among ecosystem types under limestone areas, indicating that lithology controls the pattern of microbial phosphorus Limitation along the post-agriculture succession. Our study describes a general pattern of microbial Resource Limitation in karst ecosystems, and we suggest that lithology may provide a new mechanism for explaining the variations of microbial Resource Limitation along the post-agriculture succession in different regions.
Emily C Farrer - One of the best experts on this subject based on the ideXlab platform.
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teasing apart plant community responses to n enrichment the roles of Resource Limitation competition and soil microbes
Ecology Letters, 2016Co-Authors: Emily C Farrer, Katharine N SudingAbstract:Although ecologists have documented the effects of nitrogen enrichment on productivity, diversity and species composition, we know little about the relative importance of the mechanisms driving these effects. We propose that distinct aspects of environmental change associated with N enrichment (Resource Limitation, asymmetric competition, and interactions with soil microbes) drive different aspects of plant response. We test this in greenhouse mesocosms, experimentally manipulating each factor across three ecosystems: tallgrass prairie, alpine tundra and desert grassland. We found that Resource Limitation controlled productivity responses to N enrichment in all systems. Asymmetric competition was responsible for diversity declines in two systems. Plant community composition was impacted by both asymmetric competition and altered soil microbes, with some contributions from Resource Limitation. Results suggest there may be generality in the mechanisms of plant community change with N enrichment. Understanding these links can help us better predict N response across a wide range of ecosystems.
