Carbon and phosphorus losses from dairy pasture in South Australia

Soil Research ◽  
2001 ◽  
Vol 39 (5) ◽  
pp. 969 ◽  
Author(s):  
N. K. Fleming ◽  
J. W. Cox
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Overland Flow ◽  
Dissolved Inorganic Carbon ◽  
South Australia ◽  
Annual Rainfall ◽  
Carbon Loss ◽  
Dissolved Carbon ◽  
Time Of Year ◽  
Phosphorus Losses

Runoff (overland flow and A/B horizon interflow) was measured from 2 grazed dairy pastures at Flaxley, South Australia, from 1996 to 1998. Runoff ranged from 0.4% to 10% of annual rainfall and >90% of this was overland flow. Phosphorus and carbon were measured in runoff. As much as 2.3 kg/ha of phosphorus and 10.7 kg/ha of total dissolved carbon were lost from the subcatchments in the wettest year. Over the study period, 98% of total phosphorus and 86% of total dissolved carbon were lost in overland flow. Around 45% of phosphorus was dissolved and 69% of total dissolved carbon was dissolved organic carbon. The proportion of phosphorus present in the particulate form decreased during each runoff season, and was highest in the wettest year. There was no consistent trend in the proportion of total dissolved carbon present as dissolved organic carbon because the factors found to affect dissolved organic carbon loss were different from those affecting dissolved inorganic carbon loss. Predictive relationships based on factors such as the time of year when the storm occurred and runoff volume have been developed from the 3 years of data and they explain a high proportion of variability of phosphorus and carbon loads.

Chemical concentrations of overland flow and throughflow from pastures on sloping texture-contrast soils

2001 ◽  
Vol 52 (2) ◽  
pp. 211 ◽  
Author(s):  
J. W. Cox ◽  
A. Pitman
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Overland Flow ◽  
South Australia ◽  
Annual Rainfall ◽  
Nitrate Losses ◽  
Nitrate Concentrations ◽  
Texture Contrast ◽  
Carbon Losses ◽  
Carbon Concentrations

Shallow drains are increasingly being installed to allow cropping and improve pastures in soils prone to waterlogging. Concentrations and loads of a range of chemicals including nitrate, dissolved organic carbon, and phosphorus were measured in overland flow and throughflow (drainage) from grazed standard and improved pastures in a region of the Adelaide Hills, South Australia, with 544 mm annual rainfall. In low to average rainfall years, nitrate losses from standard pastures were up to 21 times higher in throughflow (up to 0.3 kg/ha.year) than in overland flow. Dissolved organic carbon losses from standard pastures were also highest in throughflow (up to 3.5 kg/ha.year) as were loads of Na, Cl, Al, Fe, K, and Mg. Total P loads were higher in throughflow (0.15 kg/ha.year) than in overland flow. However, P concentrations in throughflow were similar to overland flow (up to 0.5 mg/L). Chemical loads from improved pastures were higher in throughflow than in overland flow. Nitrate, dissolved organic carbon, and P losses from improved pastures were up to 0.8, 8.5, and 0.1 kg/ha.year, respectively. Improved pastures had higher dissolved organic carbon concentrations (14 mg/L) and nitrate concentrations than either the standard pastures or those reported off some dairy pastures in the region. Nitrate concentrations were highest in throughflow in subsurface tube drains below the improved pastures (up to 67 mg/L).

Stable carbon isotope analysis of dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) in natural waters - Results from a worldwide proficiency test

2013 ◽  
Vol 27 (18) ◽  
pp. 2099-2107 ◽  
Author(s):  
Robert van Geldern ◽  
Mahendra P. Verma ◽  
Matheus C. Carvalho ◽  
Fausto Grassa ◽  
Antonio Delgado-Huertas ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Natural Waters ◽  
Proficiency Test ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Stable Carbon Isotope ◽  
Isotope Analysis ◽  
Stable Carbon ◽  
Stable Carbon Isotope Analysis

Damming effect on carbon processing in a subtropical valley-type reservoir in the upper Mekong Basin

2020 ◽  
Author(s):  
Lin Lin
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Rainy Season ◽  
Water Discharge ◽  
River Channels ◽  
Particulate Carbon ◽  
River Continuum ◽  
Dissolved Carbon ◽  
Carbon Retention ◽  
Valley Type

<p>Damming rivers has been identified as one of the most intense artificial perturbations on carbon transportation along the river continuum. To quantify the damming effect on the riverine carbon flux in the upper Mekong River, seasonal carbon fluxes were monitored in a subtropical valley-type reservoir (the Gongguoqiao Reservoir) in 2016. Annually, around 20% of the incoming carbon was sequestered within the reservoir with most of the carbon retention occurring in the rainy season. Since higher rainfalls and water discharge brought large amounts of terrestrial carbon into the reservoir in summer, the concentrations of dissolved organic carbon (DIC), particulate inorganic carbon (PIC) and particulate organic carbon (POC) in the topwater show significant decreasing trends from the river inlet to the outlet (p<0.01). During the cooler dry season (winter), however, the damming effect was much weaker. Precipitation of PIC owing to the alkaline environment and decelerated flow velocity contributed over half of the carbon retention in the reservoir. Correlation between suspended sediment concentration and carbon concentrations reveals that heavy sedimentation also resulted in the sequestration of particulate carbon. Yet the damming impact on the flux of dissolved organic carbon (DOC) was relatively weak due to the short water retention time and refractory nature of allochthonous carbon. The anti-season operation of the dam allowed little time for the decomposition of the incoming DOC in the rainy season. The differentiation processing of the carbon flow significantly increased the dissolved carbon proportion in the outflow. The dams could be acting as filters and the effect might be exacerbated in the cascading system. Accumulation of dissolved organic carbon possibly can accelerate eutrophication processes in the downstream reservoirs and thus altered the aquatic carbon dynamics in the downstream river channels. </p>

Effect of landuse on the composition of throughflow water immediately above clayey B horizons in the Warren Catchment, South Australia

1993 ◽  
Vol 33 (2) ◽  
pp. 239 ◽  
Author(s):  
R Naidu ◽  
DR Williamson ◽  
RW Fitzpatrick ◽  
IO Hollingsworth
Keyword(s):  
Electrical Conductivity ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Organic Compounds ◽  
South Australia ◽  
Total Dissolved Solids ◽  
Rate Of Change ◽  
Native Woodland ◽  
Colloidal Matter ◽  
Dissolved Organic Compounds

The effect of landuse on composition of throughflow water immediately above the clayey B horizons in duplex soils (mostly natric and/or sodic) in the Mount Lofty Ranges, South Australia, was investigated using simple lysimeters. During July-November 1991, the pH of the first flow immediately after rainstorm under pines, native woodland, and pasture, respectively, was 5.7, 6.0, and 6.4. At each of the sites, average pH over 4 months during July-November was 5.8-5.9. Both the electrical conductivity (EC) and the amounts of total dissolved solids (TDS) were 2-3 times higher under pine than at other sites. The rate of change in EC with respect to TDS varied considerably among the sites, possibly due to the large differences in the concentration of dissolved organic compounds. Although the pH of water was >5.5, both aluminium and iron were recorded, especially under pine, where there were also high levels of dissolved organic compounds. High levels of suspended colloidal matter were recorded in the water flowing under pine, and these levels were related to dissolved organic carbon.

scholarly journals Migration and transformation of dissolved carbon during accumulated cyanobacteria decomposition in shallow eutrophic lakes: a simulated microcosm study

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5922 ◽  
Author(s):  
Zhichun Li ◽  
Yanping Zhao ◽  
Xiaoguang Xu ◽  
Ruiming Han ◽  
Mingyue Wang ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Carbon Cycling ◽  
Dissolved Inorganic Carbon ◽  
Eutrophic Lakes ◽  
Overlying Water ◽  
Dissolved Carbon ◽  
Laboratory Microcosm ◽  
Transformation Mechanisms ◽  
Diffusive Fluxes ◽  
Sediment Interface

The decomposition processes of accumulated cyanobacteria can release large amounts of organic carbon and affect the carbon cycling in shallow eutrophic lakes. However, the migration and transformation mechanisms of dissolved carbon (DC) require further study and discussion. In this study, a 73-day laboratory microcosm experiment using suction samplers (Rhizon and syringe) was conducted to understand the migration and transformation of DC during the cyanobacteria decomposition. The decomposition of cyanobacteria biomass caused anoxic and reduction conditions, and changed the acid-base environment in the water column. During the early incubation (days 0–18), a large amount of cyanobacteria-derived particulate organic matter (POM) was decomposed into dissolved organic carbon (DOC) in the overlying water, reaching the highest peak value of 1.82 g L−1 in the treatment added the high cyanobacteria biomass (470 g). After 18 days of incubation, the mineralization of increased DOC to dissolved inorganic carbon (DIC) maintained a high DIC level of overlying water in treatments added cyanobacteria biomass. The treatment added the medium cyanobacteria biomass (235 g) presented the lower DOC/total dissolved carbon ratio than the high cyanobacteria biomass associated with the lower mineralization from DOC to DIC. Due to the concentration differences of DIC at water-sediment interface, the main migration of DIC from pore water to overlying water occurred in the treatment without added cyanobacteria biomass. However, the treatments added the cyanobacteria biomass presented the obvious diffusion of DOC and the low migration of DIC at the water-sediment interface. The diffusive fluxes of DOC at the water-sediment interface increased with the cyanobacteria biomass added, reaching the maximum value of 411.01 mg/(m2·d) in the treatment added the high cyanobacteria biomass. In the overlying water, the group added the sediment and medium cyanobacteria biomass presented a faster degradation of cyanobacteria-derived POM to DOC and a higher mineralization level of DOC to DIC than added the medium cyanobacteria biomass without sediment. Therefore, during accumulated cyanobacteria decomposition, the biomass of accumulated cyanobacteria and sediment property can influence the migration and transformation of DC, playing an important role in carbon cycling in shallow eutrophic lakes.

scholarly journals Storm Dissolved Organic Carbon Dynamics in an Artificially Drained Watershed of the US Midwest

2012 ◽  
Vol 5 ◽  
pp. ASWR.S9973 ◽  
Author(s):  
Philippe G. Vidon ◽  
Hilary A Hubbard ◽  
Pilar E. Cuadra ◽  
Matthew L. Hennessy
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Overland Flow ◽  
Agricultural Watershed ◽  
Antecedent Moisture ◽  
Tile Drains ◽  
The Us ◽  
Moisture Conditions ◽  
Subsurface Drains ◽  
Antecedent Moisture Conditions

This study investigates changes in the nature, concentrations, and fluxes of dissolved organic carbon (DOC) in tile drains (aka subsurface drains), overland flow, and stream flow for 6 spring storms in an artificially drained agricultural watershed. For moderate size storms, DOC concentrations are primarily affected by variations in antecedent moisture conditions. Generally, DOC concentrations and aromaticity increase with flow, especially for storms associated with high antecedent moisture conditions. A shift in the source of DOC to the stream and tile drains from low aromaticity DOC at baseflow, to more aromatic DOC during storms was observed. Data indicates that increases in the frequency and intensity of large precipitation events as well as wetter conditions in spring would likely lead not only to an increase in DOC fluxes (simply because of higher discharge) but also to an increase in the amount of DOC exported for every unit of flow.

scholarly journals Algal responses to dissolved organic carbon loss and pH decline during whole-lake acidification: Evidence from paleolimnology

1999 ◽  
Vol 44 (3part2) ◽  
pp. 757-773 ◽  
Author(s):  
P. R. Leavitt ◽  
D. L. Findlay ◽  
R. I. Hall ◽  
J. P. Smol
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Lake Acidification ◽  
Carbon Loss

Influence of catchment topography on water chemistry in southeastern Québec Shield lakes

1997 ◽  
Vol 54 (10) ◽  
pp. 2215-2227 ◽  
Author(s):  
Pierre D'Arcy ◽  
Richard Carignan
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Water Chemistry ◽  
Surface Waters ◽  
Overland Flow ◽  
Canadian Shield ◽  
Chl A ◽  
Lake Water Chemistry ◽  
High Runoff ◽  
Shield Lakes

For 30 Canadian Shield lakes of southeastern Quebec, catchment slope and lake morphometry account for 50-70% of the variability of chlorophyll a (Chl a), dissolved organic carbon (DOC), total phosphorus (TP), NO3- , and NH4+ . Dissolved organic carbon, TP, Chl a, Ca, and Mg are negatively related to catchment slope, whereas NO3- and NH4+ increase with increasing slope. Concentrations of more conservative constituents (SO42-, Na, K) increase with decreasing elevation as a result of higher evapotranspiration and lower precipitation at low elevations. Catchment variables (slope, drainage area, percent wetlands) are as good predictors of Chl a (r2 = 0.7) as are water chemistry variables (TP, Ca, Mg, and pH). Dominant vegetation (deciduous vs. coniferous) has little or no influence on lake water chemistry. Hydrogeological data for the Canadian Shield suggest that, during periods of high runoff, the development of waterlogged areas and the importance of overland flow on saturated soils are inversely proportional to catchment slope. We propose that the strong influence of catchment slope on water quality is due to slope-dependent seasonal waterlogging, which determines the fate (retention or export to surface waters) of dissolved substances produced within and moving through the forest floor.

scholarly journals Dissolved organic carbon loss from Yedoma permafrost amplified by ice wedge thaw

2013 ◽  
Vol 8 (3) ◽  
pp. 035023 ◽  
Author(s):  
J E Vonk ◽  
P J Mann ◽  
K L Dowdy ◽  
A Davydova ◽  
S P Davydov ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Carbon Loss ◽  
Ice Wedge
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