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Woo-jung Choi - One of the best experts on this subject based on the ideXlab platform.
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Biomass, chemical composition, and microbial Decomposability of rice root and straw produced under co-elevated CO_2 and temperature
Biology and Fertility of Soils, 2020Co-Authors: Hyun-jin Park, Jin-hyeob Kwak, Hye Yang, Woo-jung ChoiAbstract:Rice residue including root and straw are unique carbon (C) source in paddy soils. However, the potential changes in quantity and chemical composition of rice residue under co-elevated atmospheric CO_2 concentration ([CO_2]) and air temperature (T_air) and the legacy effect of the changed chemical composition on residue decomposition have not been investigated. This study was conducted to investigate biomass, chemical composition, and Decomposability of rice root and straw produced under elevated [CO_2] and T_air. Root and straw biomass increased by elevated [CO_2] and elevated T_air, respectively, and the greatest biomass was achieved under co-elevated [CO_2]-T_air for both root and straw. The concentration of lignin (recalcitrant) decreased while that of nonstructural carbohydrates (less recalcitrant) increased by co-elevated [CO_2]-T_air. The ratio of lignin-to-nitrogen (lignin/N) decreased by co-elevated [CO_2]-T_air compared to ambient [CO_2]-T_air due to increased N and decreased lignin concentrations. Decomposability of root (lignin/N, 36.4) produced under co-elevated [CO_2]-T_air was greater than that under ambient co-elevated [CO_2]-T_air (lignin/N, 53.7); however, there was no difference in Decomposability for straw, which had relatively narrow range of lignin/N (27.3–36.5) regardless of [CO_2]-T_air conditions. The results of this study provide a novel insight into the changes in quantity and quality of rice residue under elevated [CO_2]-T_air that are necessary to predict changes in paddy soil C sequestration under global warming.
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Biomass, chemical composition, and microbial Decomposability of rice root and straw produced under co-elevated CO2 and temperature
Biology and Fertility of Soils, 2020Co-Authors: Hyun-jin Park, Jin-hyeob Kwak, Sang-sun Lim, Kwang-seung Lee, Hye In Yang, Han-yong Kim, Sang-mo Lee, Woo-jung ChoiAbstract:Rice residue including root and straw are unique carbon (C) source in paddy soils. However, the potential changes in quantity and chemical composition of rice residue under co-elevated atmospheric CO2 concentration ([CO2]) and air temperature (Tair) and the legacy effect of the changed chemical composition on residue decomposition have not been investigated. This study was conducted to investigate biomass, chemical composition, and Decomposability of rice root and straw produced under elevated [CO2] and Tair. Root and straw biomass increased by elevated [CO2] and elevated Tair, respectively, and the greatest biomass was achieved under co-elevated [CO2]-Tair for both root and straw. The concentration of lignin (recalcitrant) decreased while that of nonstructural carbohydrates (less recalcitrant) increased by co-elevated [CO2]-Tair. The ratio of lignin-to-nitrogen (lignin/N) decreased by co-elevated [CO2]-Tair compared to ambient [CO2]-Tair due to increased N and decreased lignin concentrations. Decomposability of root (lignin/N, 36.4) produced under co-elevated [CO2]-Tair was greater than that under ambient co-elevated [CO2]-Tair (lignin/N, 53.7); however, there was no difference in Decomposability for straw, which had relatively narrow range of lignin/N (27.3–36.5) regardless of [CO2]-Tair conditions. The results of this study provide a novel insight into the changes in quantity and quality of rice residue under elevated [CO2]-Tair that are necessary to predict changes in paddy soil C sequestration under global warming.
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co elevated co2 and temperature and changed water availability do not change litter quantity and quality of pine and oak
Agricultural and Forest Meteorology, 2020Co-Authors: Hyun-jin Park, Jin-hyeob Kwak, Hye In Yang, Sein Park, Seung Won Oh, Woo-jung ChoiAbstract:Abstract Elevated CO2 concentration ([CO2]) and air temperature (Tair) as well as changed soil water availability (Wsoil) may affect quantity, chemistry, and microbial Decomposability of tree leaf litter. However, our understanding is limited mainly to the effect of elevated [CO2]. This study investigated the effects of elevated [CO2] and Tair in combination with two Wsoil regimes on the quantity and chemistry including the ratio of lignin to nitrogen (lignin/N) of litter produced by Pinus densiflora and Quercus variabilis saplings, and microbial respiration of the soils amended with the litters. Either elevated [CO2] or high Wsoil alone increased litter production; meanwhile elevated Tair alone decreased litter production. However, co-elevation of [CO2] and Tair did not change litter production regardless of Wsoil regime for both species. Among litter chemistry, the lignin/N, which is a robust indicator of litter Decomposability, of litter was changed in parallel with litter quantity (i.e., lignin/N ratio increased when litter quantity increased and vice versa) mainly due to dilution of N. Due to the opposite effect of warming and elevated [CO2] on litter quantity, lignin/N was not changed under co-elevated [CO2] and Tair at a given Wsoil regime for both species. Other litter chemistry including non-structural carbohydrates and minerals was also affected by [CO2], Tair, or Wsoil. However, changed litter chemistry did not change the CO2 emission from the soils amended with the litters; however, addition of litter with low lignin/N and high nutrients increased microbial biomass in the soil. This study enlarges our understanding of the effects of changed climatic variables on litter quantity, chemistry, and microbial Decomposability and suggests that co-elevation of [CO2] and Tair may not cause a significant change in the litter parameters regardless of Wsoil. Study with mature trees at a natural forest should further improve our understanding.
David A. Wardle - One of the best experts on this subject based on the ideXlab platform.
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the within species leaf economic spectrum does not predict leaf litter Decomposability at either the within species or whole community levels
Journal of Ecology, 2013Co-Authors: Benjamin G Jackson, Duane A Peltzer, David A. WardleAbstract:Summary 1. Despite recent progress in characterizing the within-species variability (WSV) of plant functional traits, the importance of this WSV in driving ecological processes such as leaf litter Decomposability within species or at the whole community level is poorly understood. 2. We ask whether leaf and litter functional traits vary within species to form a spectrum of variability analogous to the leaf economics spectrum that occurs among species. We also ask whether this spectrum of trait variation within species is an important driver of leaf litter Decomposability. To address these questions, we quantified both WSV and between-species variation of leaf and litter traits and litter Decomposability of 16 co-occurring temperate rain forest plant species along soil toposequences characterized by strong shifts in soil nutrient status in New Zealand. 3. We found considerable WSV of both leaf and litter traits for all species, and a within-species spectrum of coordinated trait variation for 11 species. The WSV of leaf and to a lesser extent foliar litter C to N and C to P values were often strongly related to soil C to N and C to P ratios across plots. Further, in many cases, WSV and its covariation with species turnover contributed significantly to the community-level aggregate trait response to variation in soil fertility. 4. Contrary to our expectations, the WSV in leaf and litter traits did not generally predict withinspecies variation in leaf litter mass loss, nor N and P release, during decomposition. Further, inclusion of WSV did not improve predictions of leaf litter Decomposability using community-level trait measures. 5. Synthesis. Our findings support the view that WSV of plant functional traits is an important component of plant community responses to environmental factors such as soil fertility. However, the apparent decoupling of WSV of leaf economic traits from WSV of ecological processes such as litter Decomposability suggests that consideration of WSV may not be necessary to understand the contributions of trait variation to determining the breakdown of plant litter and therefore, potentially, ecosystem processes.
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are functional traits and litter Decomposability coordinated across leaves twigs and wood a test using temperate rainforest tree species
Oikos, 2013Co-Authors: Benjamin G Jackson, Duane A Peltzer, David A. WardleAbstract:This study compared the Decomposability of leaf, twig and wood litter from 27 co-occurring temperate rainforest tree species in New Zealand. We found that interspecific variation in decomposition was not coordinated across the three litter types. Analysis of the relationships between functional traits and decomposition revealed that traits predictive of wood decomposition varied among the species independently from traits predictive of the decomposition of leaf and twig litter. We conclude that efforts to understand how tree species influence C, N and P dynamics in forested ecosystems through the decomposition pathway need to consider the functional traits of multiple plant structures. Synthesis Plant functional traits are increasingly used to evaluate changes in ecological and ecosystem processes. However our understanding of how functional traits coordinate across different plant structures, and the implications for trait-driven processes such as litter decomposition, remains limited. We compared the functional traits of green leaves and leaf, twig and wood litter among 27 co-occurring tree species from New Zealand, and quantified the loss of mass, N and P from the three litter types during decomposition. We hypothesised that: a) the functional traits of green leaves, and leaf, twig and wood litter are co-ordinated so that species which produce high quality leaves and leaf litter will also produce high quality twig and wood litter, and b) the Decomposability of leaf, twig and wood litter is coordinated because breakdown of all three litter types is driven by similar combinations of traits. Trait variation across species was co-ordinated between leaves, twigs and wood when angiosperm and gymnosperm species were considered in combination, or when angiosperms were considered separately, but trait coordination was poor for gymnosperms. There was little coordination among the three litter types in their Decomposability, especially when angiosperms and gymnosperms were considered separately; this was caused by the Decomposability of each of the three litter types, at least partially, being driven by different functional traits or trait combinations. Our findings indicate that although interspecific variation in the functional traits of trees can be coordinated among leaves, twigs and wood, different or unrelated traits predict the decomposition of these different structures. Furthermore, leaf-level analyses of functional traits are not satisfactory proxies for function of whole trees and related ecological processes. As such, efforts to understand how tree species influence C, N and P dynamics in forested ecosystems through the decomposition pathway need to consider functional traits of other plant structures.
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the impact of secondary compounds and functional characteristics on lichen palatability and decomposition
Journal of Ecology, 2013Co-Authors: Johan Asplund, David A. WardleAbstract:Summary There has been much recent interest in understanding how functional traits of vascular plant species drive ecological processes such as herbivory and litter decomposition. In plants, these two processes are often driven by the same or similar suites of traits and therefore correlate across species. However, few studies have considered how traits of plant-like life forms such as lichens determine species differences in their effects on ecological processes. This is despite the significant contribution of lichens to carbon and nutrient cycling in many environments. We collected 28 lichen species that differed in their growth form, substrate type and capacity to fix N, and determined key traits for each species. For each species, we performed a feeding bioassay using the generalist snail Cepaea hortensis and carried out a laboratory bioassay to assess Decomposability. We did these tests both with intact lichen material containing natural concentrations of carbon-based secondary compounds (CBSCs), and material that had been acetone rinsed to reduce concentrations of CBSCs, to evaluate the effect of CBSC on palatability and Decomposability. We found that reducing CBSC concentrations greatly increased palatability for 17 species, and Decomposability of 10 species. However, Decomposability was correlated with several lichen traits while palatability was not, regardless of whether or not CBSCs were removed, and we therefore found no relationship between Decomposability and palatability across species. Decomposability and palatability both varied, but in contrasting directions, among N-fixing vs. non-fixing lichens, lichens with different growth forms and those from contrasting substrate types. As such, N-fixing lichens had higher decomposition rates but lower consumption rates than non-fixing lichens, while foliose species had higher decomposition rates but lower consumption rates than fruticose species. Synthesis: We have shown that lichen CBSCs regulate key processes such as lichenivory and decomposition, that lichen Decomposability but not palatability are related to traits, and that these two processes are unrelated across species. These results highlight the potential role of lichen species differences in influencing ecosystem processes relating to decomposition and nutrient cycling and the role that grazers may play in driving this.
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plant traits leaf palatability and litter Decomposability for co occurring woody species differing in invasion status and nitrogen fixation ability
Functional Ecology, 2010Co-Authors: Hiroko Kurokawa, Duane A Peltzer, David A. WardleAbstract:Summary 1. Non-native invasive and nitrogen (N)-fixing plant species can cause large ecosystem-level impacts, particularly when they differ in functionally important plant traits from native and non N-fixing species. However, it remains unclear as to whether and how plant invasion status and N fixation ability consistently influence key plant leaf and litter traits, and trait-driven processes like herbivory and decomposition. 2. We compared leaf and litter traits, leaf palatability and litter Decomposability for 41 co-occurring woody species, including native N-fixers, native non N-fixers, invasive N-fixers and invasive non N-fixers, from a New Zealand floodplain. We tested the hypotheses that: (i) invasive and N-fixing species have higher foliar N and specific leaf area, and lower concentrations of defensive phenolics and structural compounds than do native and non N-fixing species, and (ii) invasive and N-fixing species generally produce more decomposable litter and palatable foliage than do native and non N-fixing species. 3. Consistent with our hypotheses, invaders had higher foliar N and N : P ratio, and lower C : N ratio, than did native species. However, in contrast to our hypotheses, foliar phenolics were higher for the invaders while other leaf and litter traits were unaffected by invasion status. Further, N-fixers had higher N and N : P ratios, and lower C : N ratios than did non N-fixers, but other leaf and litter traits were unaffected by N fixation ability. 4. Leaf palatability was unaffected by invasion status but was higher for N-fixers than for non N-fixers. Litter Decomposability was unaffected both by invasion status and N fixation ability. We found a significant positive relationship between leaf palatability and litter Decomposability across all species, because similar traits, particularly the C : P ratio and total phenolic concentrations of plant tissues, were correlated with both processes. 5. Our results demonstrate that a small number of key traits, such as C : P ratio and total phenolic concentrations, drive both herbivory and decomposition irrespective of plant invasion status or N fixation ability. As such, they highlight that interspecific differences in particular plant traits, rather than plant functional group memberships based on invasion status and N fixation ability, are more effective in predicting palatability and Decomposability.
Michail Zak - One of the best experts on this subject based on the ideXlab platform.
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QCQC - Quantum Resonance for Solving NP-complete Problems by Simulations
Quantum Computing and Quantum Communications, 1999Co-Authors: Michail ZakAbstract:Quantum analog computing is based upon similarity between mathematical formalism of a quantum phenomenon and phenomena to be analyzed. In this paper, the mathematical formalism of quantum resonance combined with tensor product Decomposability of unitary evolutions is mapped onto a class of NP-complete combinatorial problems.
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Quantum resonance for solving NP-complete problems by simulations
Lecture Notes in Computer Science, 1999Co-Authors: Michail ZakAbstract:Quantum analog computing is based upon similarity between mathematical formalism of a quantum phenomenon and phenomena to be analyzed. In this paper, the mathematical formalism of quantum resonance combined with tensor product Decomposability of unitary evolutions is mapped onto a class of NP-complete combinatorial problems.
William K. Cornwell - One of the best experts on this subject based on the ideXlab platform.
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burn or rot leaf traits explain why flammability and Decomposability are decoupled across species
Functional Ecology, 2015Co-Authors: Saskia Grootemaat, Johannes Hc Cornelissen, Ian J Wright, Peter M Van Bodegom, William K. CornwellAbstract:Summary In fireprone ecosystems, two important alternative fates for leaves are burning in a wildfire (when alive or as litter) or they get consumed (as litter) by decomposers. The influence of leaf traits on litter decomposition rate is reasonably well understood. In contrast, less is known about the influence of leaf traits on leaf and litter flammability. The aim of this study was twofold: (i) to determine which morphological and chemical leaf traits drive flammability and (ii) to determine whether different (combinations of) morphological and chemical leaf traits drive interspecific variation in decomposition and litter flammability and, in turn, help us understand the relationship between Decomposability and flammability. To explore the relationships between leaf traits and flammability of individual leaves, we used 32 evergreen perennial plant species from eastern Australia in standardized experimental burns on three types of leaf material (i.e. fresh, dried and senesced). Next, we compared these trait–flammability relationships to trait–Decomposability relationships as obtained from a previous decomposition experiment (focusing on senesced leaves only). Within the three parameters of leaf flammability that we measured, interspecific variation in time to ignition was mainly explained by specific leaf area and moisture content. Flame duration and smoulder duration were mostly explained by leaf dry mass and to a lesser degree by leaf chemistry, namely, nitrogen, phosphorus and tannin concentrations. The variation in the decomposition constant across species was unrelated to our measures of flammability. Moreover, different combinations of morphological and chemical leaf properties underpinned the interspecific variation in Decomposability and flammability. In contrast to litter flammability, Decomposability was driven by lignin and phosphorus concentrations. The decoupling of flammability and Decomposability leads to three possible scenarios for species’ influence on litter fates: (i) fast-decomposing species for which flammability is irrelevant because there will not be enough litter to support a fire; (ii) species with slow-decomposing leaves and a high flammability; and (iii) species with slow-decomposing leaves and a low flammability. We see potential for making use of the decoupled trait–decomposition–flammability relationships when modelling carbon and nutrient fluxes. Including information on leaf traits in models can improve the prediction of fire behaviour. We note that herbivory is another key fate for leaves, but this study was focused on fire and decomposition.
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global relationship of wood and leaf litter Decomposability the role of functional traits within and across plant organs
Global Ecology and Biogeography, 2014Co-Authors: Katherina A Pietsch, Johannes Hc Cornelissen, William K. Cornwell, Kiona Ogle, Gerhard Bonisch, Joseph M Craine, Benjamin G Jackson, Jens Kattge, Duane A Peltzer, Josep PenuelasAbstract:Aim Recent meta-analyses have revealed that plant traits and their phylogenetic history influence decay rates of dead wood and leaf litter, but it remains unknown if decay rates of wood and litter covary over a wide range of tree species and across ecosystems. We evaluated the relationships between species-specific wood and leaf litter Decomposability, as well as between wood and leaf traits that control their respective Decomposability. Location Global. Methods We compiled data on rates of wood and leaf litter decomposition for 324 and 635 tree species, respectively, and data on six functional traits for both organs. We used hierarchical Bayesian meta-analysis to estimate, for the first time, species-specific values for wood and leaf litter Decomposability standardized to reference conditions (k*wood and k*leaf) across the globe. With these data, we evaluated the relationships: (1) between wood and leaf traits, (2) between each k* and the selected traits within and across organs, and (3) between wood and leaf k*. Results Across all species k*wood and k*leaf were positively correlated, phylogenetically clustered and correlated with plant functional traits within and across organs. k* of both organs was usually better described as a function of within- and cross-organ traits, than of within-organ traits alone. When analysed for angiosperms and gymnosperms separately, wood and leaf k* were no longer significantly correlated, but each k* was still significantly correlated to the functional traits. Main conclusions We demonstrate important relationships among wood and leaf litter Decomposability as after-life effects of traits from the living plants. These functional traits influence the Decomposability of senesced tissue which could potentially lead to alterations in the rates of biogeochemical cycling, depending on the phylogenetic structure of the species pool. These results provide crucial information for a better representation of decomposition rates in dynamic global vegetation models.
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Experimental evidence that the Ornstein-Uhlenbeck model best describes the evolution of leaf litter Decomposability
Ecology and Evolution, 2014Co-Authors: Xu Pan, Johannes Hc Cornelissen, Wei-wei Zhao, Guo-fang Liu, Andreas Prinzing, Ming Dong, William K. CornwellAbstract:Leaf litter Decomposability is an important effect trait for ecosystem function-ing. However, it is unknown how this effect trait evolved through plant history as a leaf 'afterlife' integrator of the evolution of multiple underlying traits upon which adaptive selection must have acted. Did Decomposability evolve in a Brownian fashion without any constraints? Was evolution rapid at first and then slowed? Or was there an underlying mean-reverting process that makes the evolution of extreme trait values unlikely? Here, we test the hypothesis that the evolution of Decomposability has undergone certain mean-reverting forces due to strong constraints and trade-offs in the leaf traits that have afterlife effects on litter quality to decomposers. In order to test this, we examined the leaf litter Decomposability and seven key leaf traits of 48 tree species in the tem-perate area of China and fitted them to three evolutionary models: Brownian motion model (BM), Early burst model (EB), and Ornstein-Uhlenbeck model (OU). The OU model, which does not allow unlimited trait divergence through time, was the best fit model for leaf litter Decomposability and all seven leaf traits. These results support the hypothesis that neither Decomposability nor the underlying traits has been able to diverge toward progressively extreme values through evolutionary time. These results have reinforced our understanding of the relationships between leaf litter Decomposability and leaf traits in an evolu-tionary perspective and may be a helpful step toward reconstructing deep-time carbon cycling based on taxonomic composition with more confidence.
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plant species traits are the predominant control on litter decomposition rates within biomes worldwide
Ecology Letters, 2008Co-Authors: William K. Cornwell, Johannes Hc Cornelissen, Kathryn L Amatangelo, Ellen Dorrepaal, Valerie T Eviner, Oscar Godoy, Sarah E Hobbie, Bart Hoorens, Hiroko KurokawaAbstract:Worldwide decomposition rates depend both on climate and the legacy of plant functional traits as litter quality. To quantify the degree to which functional differentiation among species affects their litter decomposition rates, we brought together leaf trait and litter mass loss data for 818 species from 66 decomposition experiments on six continents. We show that: (i) the magnitude of species-driven differences is much larger than previously thought and greater than climate-driven variation; (ii) the Decomposability of a species litter is consistently correlated with that species ecological strategy within different ecosystems globally, representing a new connection between whole plant carbon strategy and biogeochemical cycling. This connection between plant strategies and Decomposability is crucial for both understanding vegetation–soil feedbacks, and for improving forecasts of the global carbon cycle.
Hyun-jin Park - One of the best experts on this subject based on the ideXlab platform.
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Biomass, chemical composition, and microbial Decomposability of rice root and straw produced under co-elevated CO_2 and temperature
Biology and Fertility of Soils, 2020Co-Authors: Hyun-jin Park, Jin-hyeob Kwak, Hye Yang, Woo-jung ChoiAbstract:Rice residue including root and straw are unique carbon (C) source in paddy soils. However, the potential changes in quantity and chemical composition of rice residue under co-elevated atmospheric CO_2 concentration ([CO_2]) and air temperature (T_air) and the legacy effect of the changed chemical composition on residue decomposition have not been investigated. This study was conducted to investigate biomass, chemical composition, and Decomposability of rice root and straw produced under elevated [CO_2] and T_air. Root and straw biomass increased by elevated [CO_2] and elevated T_air, respectively, and the greatest biomass was achieved under co-elevated [CO_2]-T_air for both root and straw. The concentration of lignin (recalcitrant) decreased while that of nonstructural carbohydrates (less recalcitrant) increased by co-elevated [CO_2]-T_air. The ratio of lignin-to-nitrogen (lignin/N) decreased by co-elevated [CO_2]-T_air compared to ambient [CO_2]-T_air due to increased N and decreased lignin concentrations. Decomposability of root (lignin/N, 36.4) produced under co-elevated [CO_2]-T_air was greater than that under ambient co-elevated [CO_2]-T_air (lignin/N, 53.7); however, there was no difference in Decomposability for straw, which had relatively narrow range of lignin/N (27.3–36.5) regardless of [CO_2]-T_air conditions. The results of this study provide a novel insight into the changes in quantity and quality of rice residue under elevated [CO_2]-T_air that are necessary to predict changes in paddy soil C sequestration under global warming.
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Biomass, chemical composition, and microbial Decomposability of rice root and straw produced under co-elevated CO2 and temperature
Biology and Fertility of Soils, 2020Co-Authors: Hyun-jin Park, Jin-hyeob Kwak, Sang-sun Lim, Kwang-seung Lee, Hye In Yang, Han-yong Kim, Sang-mo Lee, Woo-jung ChoiAbstract:Rice residue including root and straw are unique carbon (C) source in paddy soils. However, the potential changes in quantity and chemical composition of rice residue under co-elevated atmospheric CO2 concentration ([CO2]) and air temperature (Tair) and the legacy effect of the changed chemical composition on residue decomposition have not been investigated. This study was conducted to investigate biomass, chemical composition, and Decomposability of rice root and straw produced under elevated [CO2] and Tair. Root and straw biomass increased by elevated [CO2] and elevated Tair, respectively, and the greatest biomass was achieved under co-elevated [CO2]-Tair for both root and straw. The concentration of lignin (recalcitrant) decreased while that of nonstructural carbohydrates (less recalcitrant) increased by co-elevated [CO2]-Tair. The ratio of lignin-to-nitrogen (lignin/N) decreased by co-elevated [CO2]-Tair compared to ambient [CO2]-Tair due to increased N and decreased lignin concentrations. Decomposability of root (lignin/N, 36.4) produced under co-elevated [CO2]-Tair was greater than that under ambient co-elevated [CO2]-Tair (lignin/N, 53.7); however, there was no difference in Decomposability for straw, which had relatively narrow range of lignin/N (27.3–36.5) regardless of [CO2]-Tair conditions. The results of this study provide a novel insight into the changes in quantity and quality of rice residue under elevated [CO2]-Tair that are necessary to predict changes in paddy soil C sequestration under global warming.
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co elevated co2 and temperature and changed water availability do not change litter quantity and quality of pine and oak
Agricultural and Forest Meteorology, 2020Co-Authors: Hyun-jin Park, Jin-hyeob Kwak, Hye In Yang, Sein Park, Seung Won Oh, Woo-jung ChoiAbstract:Abstract Elevated CO2 concentration ([CO2]) and air temperature (Tair) as well as changed soil water availability (Wsoil) may affect quantity, chemistry, and microbial Decomposability of tree leaf litter. However, our understanding is limited mainly to the effect of elevated [CO2]. This study investigated the effects of elevated [CO2] and Tair in combination with two Wsoil regimes on the quantity and chemistry including the ratio of lignin to nitrogen (lignin/N) of litter produced by Pinus densiflora and Quercus variabilis saplings, and microbial respiration of the soils amended with the litters. Either elevated [CO2] or high Wsoil alone increased litter production; meanwhile elevated Tair alone decreased litter production. However, co-elevation of [CO2] and Tair did not change litter production regardless of Wsoil regime for both species. Among litter chemistry, the lignin/N, which is a robust indicator of litter Decomposability, of litter was changed in parallel with litter quantity (i.e., lignin/N ratio increased when litter quantity increased and vice versa) mainly due to dilution of N. Due to the opposite effect of warming and elevated [CO2] on litter quantity, lignin/N was not changed under co-elevated [CO2] and Tair at a given Wsoil regime for both species. Other litter chemistry including non-structural carbohydrates and minerals was also affected by [CO2], Tair, or Wsoil. However, changed litter chemistry did not change the CO2 emission from the soils amended with the litters; however, addition of litter with low lignin/N and high nutrients increased microbial biomass in the soil. This study enlarges our understanding of the effects of changed climatic variables on litter quantity, chemistry, and microbial Decomposability and suggests that co-elevation of [CO2] and Tair may not cause a significant change in the litter parameters regardless of Wsoil. Study with mature trees at a natural forest should further improve our understanding.
