scholarly journals A global model of carbon, nitrogen and phosphorus cycles for the terrestrial biosphere

2010 ◽  
Vol 7 (7) ◽  
pp. 2261-2282 ◽  
Author(s):  
Y. P. Wang ◽  
R. M. Law ◽  
B. Pak
Keyword(s):  
Organic Matter ◽  
Steady State ◽  
Soil Organic Matter ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Terrestrial Ecosystems ◽  
Plant Litter ◽  
Terrestrial Biosphere ◽  
P Limitation ◽  
P Mineralization

Abstract. Carbon storage by many terrestrial ecosystems can be limited by nutrients, predominantly nitrogen (N) and phosphorus (P), in addition to other environmental constraints, water, light and temperature. However the spatial distribution and the extent of both N and P limitation at the global scale have not been quantified. Here we have developed a global model of carbon (C), nitrogen (N) and phosphorus (P) cycles for the terrestrial biosphere. Model estimates of steady state C and N pool sizes and major fluxes between plant, litter and soil pools, under present climate conditions, agree well with various independent estimates. The total amount of C in the terrestrial biosphere is 2767 Gt C, and the C fractions in plant, litter and soil organic matter are 19%, 4% and 77%. The total amount of N is 135 Gt N, with about 94% stored in the soil, 5% in the plant live biomass, and 1% in litter. We found that the estimates of total soil P and its partitioning into different pools in soil are quite sensitive to biochemical P mineralization. The total amount of P (plant biomass, litter and soil) excluding occluded P in soil is 17 Gt P in the terrestrial biosphere, 33% of which is stored in the soil organic matter if biochemical P mineralization is modelled, or 31 Gt P with 67% in soil organic matter otherwise. This model was used to derive the global distribution and uncertainty of N or P limitation on the productivity of terrestrial ecosystems at steady state under present conditions. Our model estimates that the net primary productivity of most tropical evergreen broadleaf forests and tropical savannahs is reduced by about 20% on average by P limitation, and most of the remaining biomes are N limited; N limitation is strongest in high latitude deciduous needle leaf forests, and reduces its net primary productivity by up to 40% under present conditions.

scholarly journals A global model of carbon, nitrogen and phosphorus cycles for the terrestrial biosphere

2009 ◽  
Vol 6 (5) ◽  
pp. 9891-9944 ◽  
Author(s):  
Y. P. Wang ◽  
R. M. Law ◽  
B. Pak
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Terrestrial Ecosystems ◽  
Plant Litter ◽  
Global Model ◽  
Terrestrial Biosphere ◽  
P Limitation ◽  
P Mineralization

Abstract. Carbon storage by many terrestrial ecosystems can be limited by nutrients, predominantly nitrogen (N) and phosphorous (P), in additional to other environmental constraints, water, light and temperature. However the spatial distribution and the extent of both N and P limitation at global scale have not been quantified. Here we have developed a global model of carbon (C), nitrogen (N) and phosphorus (P) cycles for the terrestrial biosphere. Model estimates of steady state C and N pool sizes and major fluxes between plant, litter and soil pools, under present climate conditions, agree well with various independent estimates. The total amount of C in the terrestrial biosphere is 2526 Gt C, and the C fractions in plant, litter and soil organic matter are 21, 6 and 73%. The total amount of N is 124 Gt N, with about 94% stored in the soil, 5% in the plant live biomass, and 1% in litter. We found that the estimates of total soil P and its partitioning into different pools in soil are quite sensitive to biochemical P mineralization that has not been included in any other global models previously. The total amount of P is 26 Gt P in the terrestrial biosphere, 17% of which is stored in the soil organic matter if biochemical P mineralization is modelled, or 40 Gt P, with 60% in soil organic matter, otherwise. This model was used to derive the global distribution of N or P limitation on the productivity of terrestrial ecosystems. Our model predicts that the net primary productivity of most tropical evergreen broadleaf forests and tropical savannahs is reduced by about 20% on average by P limitation, and most of the remaining biomes are N limited; N limitation is strongest in high latitude deciduous needle leaf forests, and reduces its net primary productivity by up to 40% under present conditions.

scholarly journals Differential effects of redox conditions on the decomposition of litter and soil organic matter

2020 ◽  
Author(s):  
Yang Lin ◽  
Ashley N. Campbell ◽  
Amrita Bhattacharyya ◽  
Nicole DiDonato ◽  
Allison M. Thompson ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
High Resolution Mass Spectrometry ◽  
Terrestrial Ecosystems ◽  
Plant Litter ◽  
Redox Conditions ◽  
Co2 Production ◽  
Luquillo Experimental Forest ◽  
Soil Redox ◽  
Extractable Organic Matter

Abstract. Soil redox conditions exert substantial influence on biogeochemical processes in terrestrial ecosystems. Humid tropical forest soils are often characterized by fluctuating redox dynamics, yet how these dynamics affect patterns in soil versus litter decomposition and associated CO2 fluxes is not well understood. We used a 13C-labeled litter addition to explicitly follow the decomposition of litter-derived vs. native soil-derived organic matter in response to four different soil redox regimes – static oxic or anoxic, and two oscillating treatments – in soil from the Luquillo Experimental Forest, Puerto Rico. We coupled this incubation experiment with high-resolution mass spectrometry to characterize the preferential decomposition of specific classes of organic molecules. CO2 production from litter and soil organic matter (SOM) showed distinctly different responses to redox manipulation. The cumulative production of SOM-derived CO2 was positively correlated with the length of soil exposure to an oxic headspace (r = 0.89, n = 20), whereas cumulative 13C-litter-derived CO2 production was not linked to oxygen availability. The CO2 production rate from litter was highest under static anoxic conditions in the first half of the incubation period, and later dropped to the lowest among all redox treatments. In the consistently anoxic soils, we observed the depletion of more oxidized water-extractable organic matter (especially amino sugars, carbohydrates, and proteins) over time, suggesting that under anaerobic conditions, microbes preferentially used more oxidized litter-derived compounds during the early stages of decomposition. Results from kinetic modeling showed that more frequent anoxic exposure limited the decomposition of a slow-cycling C pool, but not a fast-cycling pool. Overall, our results demonstrate that substrate source – freshly added litter vs. native organic matter – plays an important role in the redox sensitivity of organic matter decomposition. In soil environments that regularly experience redox fluctuations, anaerobic heterotrophs can be surprisingly effective in degrading fresh plant litter.

scholarly journals Differential effects of redox conditions on the decomposition of litter and soil organic matter

2020 ◽  
Author(s):  
Yang Lin ◽  
Ashley N. Campbell ◽  
Amrita Bhattacharyya ◽  
Nicole DiDonato ◽  
Allison M. Thompson ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
High Resolution Mass Spectrometry ◽  
Terrestrial Ecosystems ◽  
Plant Litter ◽  
Redox Conditions ◽  
Luquillo Experimental Forest ◽  
Soil Redox ◽  
Slow Cycling ◽  
Extractable Organic Matter

AbstractSoil redox conditions exert substantial influence on biogeochemical processes in terrestrial ecosystems. Humid tropical forest soils are often characterized by fluctuating redox dynamics, yet how these dynamics affect patterns in soil versus litter decomposition and associated CO2 fluxes is not well understood. We used a 13C-labeled litter addition to explicitly follow the decomposition of litter-derived vs. native soil-derived organic matter in response to four different soil redox regimes—static oxic or anoxic, and two oscillating treatments—in soil from the Luquillo Experimental Forest, Puerto Rico. We coupled this incubation experiment with high-resolution mass spectrometry to characterize the preferential decomposition of specific classes of organic molecules. CO2 production from litter and soil organic matter (SOM) showed distinctly different responses to redox manipulation. The cumulative production of SOM-derived CO2 was positively correlated with the length of soil exposure to an oxic headspace (r = 0.89, n = 20), whereas cumulative 13C-litter-derived CO2 production was not linked to oxygen availability. The CO2 production rate from litter was highest under static anoxic conditions in the first half of the incubation period, and later dropped to the lowest among all redox treatments. In the consistently anoxic soils, we observed the depletion of more oxidized water-extractable organic matter (especially amino sugars, carbohydrates, and proteins) over time, suggesting that under anaerobic conditions, microbes preferentially used more oxidized litter-derived compounds during the early stages of decomposition. Results from kinetic modeling showed that more frequent anoxic exposure limited the decomposition of a slow-cycling C pool, but not a fast-cycling pool. Overall, our results demonstrate that substrate source—freshly added litter vs. native organic matter—plays an important role in the redox sensitivity of organic matter decomposition. In soil environments that regularly experience redox fluctuations, anaerobic heterotrophs can be surprisingly effective in degrading fresh plant litter.

scholarly journals On the potential vegetation feedbacks that enhance phosphorus availability – insights from a process-based model linking geological and ecological timescales

2014 ◽  
Vol 11 (13) ◽  
pp. 3661-3683 ◽  
Author(s):  
C. Buendía ◽  
S. Arens ◽  
T. Hickler ◽  
S. I. Higgins ◽  
P. Porada ◽  
...  
Keyword(s):  
Biomass Production ◽  
Primary Productivity ◽  
Chemical Weathering ◽  
Production Efficiency ◽  
Root Exudation ◽  
Terrestrial Ecosystems ◽  
Global Scale ◽  
P Uptake ◽  
P Availability ◽  
P Limitation

Abstract. In old and heavily weathered soils, the availability of P might be so small that the primary production of plants is limited. However, plants have evolved several mechanisms to actively take up P from the soil or mine it to overcome this limitation. These mechanisms involve the active uptake of P mediated by mycorrhiza, biotic de-occlusion through root clusters, and the biotic enhancement of weathering through root exudation. The objective of this paper is to investigate how and where these processes contribute to alleviate P limitation on primary productivity. To do so, we propose a process-based model accounting for the major processes of the carbon, water, and P cycles including chemical weathering at the global scale. Implementing P limitation on biomass synthesis allows the assessment of the efficiencies of biomass production across different ecosystems. We use simulation experiments to assess the relative importance of the different uptake mechanisms to alleviate P limitation on biomass production. We find that active P uptake is an essential mechanism for sustaining P availability on long timescales, whereas biotic de-occlusion might serve as a buffer on timescales shorter than 10 000 yr. Although active P uptake is essential for reducing P losses by leaching, humid lowland soils reach P limitation after around 100 000 yr of soil evolution. Given the generalized modelling framework, our model results compare reasonably with observed or independently estimated patterns and ranges of P concentrations in soils and vegetation. Furthermore, our simulations suggest that P limitation might be an important driver of biomass production efficiency (the fraction of the gross primary productivity used for biomass growth), and that vegetation on old soils has a smaller biomass production rate when P becomes limiting. With this study, we provide a theoretical basis for investigating the responses of terrestrial ecosystems to P availability linking geological and ecological timescales under different environmental settings.

scholarly journals Integrating plant litter quality, soil organic matter stabilization, and the carbon saturation concept

2015 ◽  
Vol 21 (9) ◽  
pp. 3200-3209 ◽  
Author(s):  
Michael J. Castellano ◽  
Kevin E. Mueller ◽  
Daniel C. Olk ◽  
John E. Sawyer ◽  
Johan Six
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Litter Quality ◽  
Plant Litter ◽  
Carbon Saturation ◽  
Organic Matter Stabilization

Rate of recycling of sulfur from urine, feces and litter applied to the soil surface

Soil Research ◽  
1994 ◽  
Vol 32 (3) ◽  
pp. 543 ◽  
Author(s):  
GJ Blair ◽  
AR Till ◽  
C Boswell
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Surface ◽  
Plant Litter ◽  
Test Plant ◽  
Soil P ◽  
S Uptake ◽  
Organic Matter Pool ◽  
Preferential Uptake ◽  
Soil Organic Matter Pool

The recycling of S from plant litter, dung and urine is an important process for supplying S for pastures. A pot experiment was conducted where 35S-labelled litter (25% white clover/38% ryegrass/21% weed) and S-35-labelled urine and faeces collected from sheep fed the same herbage as was used as litter was surface applied to pots and the fate of the applied S was followed for 100 days with ryegrass as the test plant. In camp soil, 45% of the S applied in urine was taken up by ryegrass plants within 12 days of application. In non-camp soil, the uptake of urine-S was about 20% over the same period. Cumulative uptake of 35S from urine in camp soil was subsequently restricted, with a maximum of 60% eventually measured in plants after 100 days. Mean rates of release of S (0-37 days) from litter and faeces was respectively 16.2 and 4.5 mg g-1 day-1. The calculated half-times from S in the two materials were respectively 43 and 154 days under controlled environmental conditions with adequate moisture. Litter S followed organic matter (OM) decomposition, but faecal S release was initially more rapid than faecal OM decomposition. There was little S release from faeces after day 25. Rather, S was immobilized in faeces during the 25-100 day period. The decomposition of litter and faeces was divided into an initial rapid process during which soluble S and more labile S was released, followed by a slower process involving the release of S from tissues more resistant to mineralization. The uptake of 35S from labelled materials was initially more rapid than would be expected for total S released from the added litter and faeces and the 35Suptake effect was short-lived relative to the continued effect of added material on total S uptake. The preferential uptake of 35S from the surface-applied material appears to be due to limited root development at the early stages of the experiment. Movement of 35S into the soil organic matter pool was very rapid; 58.4% of urine S was in the soil organic matter fraction in the non-camp soil by day 6. The amount of applied S in the organic matter equilibrated at about day 75. The accumulation of applied S from the materials added was greater than that recorded in previously reported studies for inorganic sulfate (e.g. about 50%). Soil P and S status had little effect on rates of release of S. from the applied materials, however, the effect of the camp and non-camp soil on total S recycling was markedly different as a result of the different amounts of plant growth and thus S uptake in the two soils. The decomposition of litter indicated peak rates of S release at two specific times over the 100 days and indicated successional changes in micro-organism activity. With faeces, the experiment was not continued for sufficiently long to show micro-organism effects.

scholarly journals Drying and rewetting conditions differentially affect the mineralization of fresh plant litter and extant soil organic matter

2018 ◽  
Vol 124 ◽  
pp. 81-89 ◽  
Author(s):  
Luis Lopez-Sangil ◽  
Iain P. Hartley ◽  
Pere Rovira ◽  
Pere Casals ◽  
Emma J. Sayer
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Plant Litter ◽  
Fresh Plant ◽  
Drying And Rewetting

Variability of ecosystem carbon source from microbial respiration is controlled by rainfall dynamics

2021 ◽  
Vol 118 (52) ◽  
pp. e2115283118
Author(s):  
Heng Huang ◽  
Salvatore Calabrese ◽  
Ignacio Rodriguez-Iturbe
Keyword(s):  
Primary Productivity ◽  
Microbial Growth ◽  
Net Primary Productivity ◽  
Carbon Sources ◽  
Terrestrial Ecosystems ◽  
Rainfall Regime ◽  
Physical Factors ◽  
Scale Parameters ◽  
Complex Interactions ◽  
Soil Heterotrophic Respiration

Soil heterotrophic respiration (Rh) represents an important component of the terrestrial carbon cycle that affects whether ecosystems function as carbon sources or sinks. Due to the complex interactions between biological and physical factors controlling microbial growth, Rh is uncertain and difficult to predict, limiting our ability to anticipate future climate trajectories. Here we analyze the global FLUXNET 2015 database aided by a probabilistic model of microbial growth to examine the ecosystem-scale dynamics of Rh and identify primary predictors of its variability. We find that the temporal variability in Rh is consistently distributed according to a Gamma distribution, with shape and scale parameters controlled only by rainfall characteristics and vegetation productivity. This distribution originates from the propagation of fast hydrologic fluctuations on the slower biological dynamics of microbial growth and is independent of biome, soil type, and microbial physiology. This finding allows us to readily provide accurate estimates of the mean Rh and its variance, as confirmed by a comparison with an independent global dataset. Our results suggest that future changes in rainfall regime and net primary productivity will significantly alter the dynamics of Rh and the global carbon budget. In regions that are becoming wetter, Rh may increase faster than net primary productivity, thereby reducing the carbon storage capacity of terrestrial ecosystems.

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