Pathways of phosphorus, nitrogen, and carbon movement over and through texturally differentiated soils, South Australia

Soil Research ◽  
1999 ◽  
Vol 37 (4) ◽  
pp. 679 ◽  
Author(s):  
D. J. Chittleborough ◽  
J. W. Cox ◽  
D. P. Stevens
Keyword(s):  
Organic Carbon ◽  
Overland Flow ◽  
South Australia ◽  
Catchment Management ◽  
Catchment Scale ◽  
Through Flow ◽  
Close Proximity ◽  
Significant Loading ◽  
Restrict Movement ◽  
Texture Contrast

One method for preventing the degradation of water supplies through contamination with phosphorus (P), nitrate (NO3), and dissolved organic carbon (DOC) is to restrict movement of these contaminants from the catchment into water bodies. The purpose of the study was to quantify and characterise the proportion of NO3, P, and DOC moving from duplex soils by overland flow and through-flow on a sub-catchment scale, and to characterise soil properties that influence their movement. Two sites in the Adelaide Hills (South Australia) with contrasting duplex soils were instrumented to collect overland flow and through-flow from the soils A and B horizon. Each site contained 2 sub-catchments in close proximity. Sub-catchments were well defined by the natural topography sloping from hillcrest to a stream headwater. Soil type, especially the degree of texture contrast, the macroporosity, and the proportion of clay in the B horizon, had a large influence on the pathways of water, and therefore P, DOC, and NO3 movement. Environmentally significant concentrations of P (>0�1 mg/L) and NO3-N (>0�5 mg/L) moved overland and through these soils in 1997. High DOC loads (25 mg/L), which would also impact on water treatment costs, moved through some soils. Significant loading of P moved through and over soils in both dissolved (0�5 mg/L) and particulate (0�3 mg/L) forms. Consequently, through-flow cannot be ignored as a contributor to P in streams and both dissolved and particulate P must be measured under these conditions to define the full impact of P. The findings from this research have implications for research on catchment management to restrict DOC and nutrient movement into waterways.

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).

Seasonal changes in pathways of dissolved organic carbon through a hillslope soil (Xeralf) with contrasting texture

Soil Research ◽  
1992 ◽  
Vol 30 (4) ◽  
pp. 465 ◽  
Author(s):  
DJ Chittleborough ◽  
KRJ Smettem ◽  
E Cotsaris ◽  
FW Leaney
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Overland Flow ◽  
Podzolic Soil ◽  
Marked Decrease ◽  
Soil Surface ◽  
Storm Events ◽  
Dry Period ◽  
Doc Concentration ◽  
Texture Contrast

The pathways of dissolved organic carbon (DOC) through a podzolic soil (Xeralf) with strong texture contrast are described. During winter, most of the DOC passes through macropores in the profile and flows laterally through the B horizons. During summer the presence of dry, hydrophobic organic matter on the soil surface and the A1 horizon causes DOC to flow overland. DOC concentrations vary seasonally. Highest concentrations are measured during summer overland flow. For all horizons, the longer the dry period the greater the DOC concentration in the subsequent flow. During storm events there is a marked flushing effect in the B horizons but in the A horizon and the surface, DOC concentrations tend to rise. There was a marked decrease in DOC concentration in flow from the B3 compared to the upper horizons. This may be due to adsorption by fine clays lining the macropores.

scholarly journals The significance and lag-time of deep through flow: an example from a small, ephemeral catchment with contrasting soil types in the Adelaide Hills, South Australia

2009 ◽  
Vol 13 (7) ◽  
pp. 1201-1214 ◽  
Author(s):  
E. Bestland ◽  
S. Milgate ◽  
D. Chittleborough ◽  
J. VanLeeuwen ◽  
M. Pichler ◽  
...  
Keyword(s):  
Stream Flow ◽  
Overland Flow ◽  
Clayey Soil ◽  
South Australia ◽  
Sandy Soils ◽  
Lag Time ◽  
Soil Horizons ◽  
Deep Soil ◽  
Soil System ◽  
Through Flow

Abstract. The importance of deep soil-regolith through flow in a small (3.4 km2) ephemeral catchment in the Adelaide Hills of South Australia was investigated by detailed hydrochemical analysis of soil water and stream flow during autumn and early winter rains. In this Mediterranean climate with strong summer moisture deficits, several significant rainfalls are required to generate soil through flow and stream flow [in ephemeral streams]. During autumn 2007, a large (127 mm) drought-breaking rain occurred in April followed by significant May rains; most of this April and May precipitation occurred prior to the initiation of stream flow in late May. These early events, especially the 127 mm April event, had low stable water isotope values compared with later rains during June and July and average winter precipitation. Thus, this large early autumn rain event with low isotopic values (δ18O, δD) provided an excellent natural tracer. During later June and July rainfall events, daily stream and soil water samples were collected and analysed. Results from major and trace elements, water isotopes (δ18O, δD), and dissolved organic carbon analysis clearly demonstrate that a large component of this early April and May rain was stored and later pushed out of deep soil and regolith zones. This pre-event water was identified in the stream as well as identified in deep soil horizons due to its different isotopic signature which contrasted sharply with the June–July event water. Based on this data, the soil-regolith hydrologic system for this catchment has been re-thought. The catchment area consists of about 60% sandy and 40% clayey soils. Regolith flow in the sandy soil system and not the clayey soil system is now thought to dominate the deep subsurface flow in this catchment. The clayey texture contrast soils had rapid response to rain events and saturation excess overland flow. The sandy soils had delayed soil through flow and infiltration excess overland flow. A pulse of macropore through flow was observed in the sandy soils three days after the rainfall event largely ended. The macropore water was a mixture of pre-event and event water, demonstrating the lag-time and mixing of the water masses in the sandy soil system. By contrast, the clayey soil horizons were not dominated by pre-event water, demonstrating the quicker response and shallow through flow of the clayey soil system. Thus, the sandy terrain has a greater vadose zone storage and greater lag time of through flow than the clayey terrain.

Chemical losses off dairy catchments located on a texture-contrast soil: carbon, phosphorus, sulfur, and other chemicals

Soil Research ◽  
1998 ◽  
Vol 36 (6) ◽  
pp. 979 ◽  
Author(s):  
N. K. Fleming ◽  
J. W. Cox
Keyword(s):  
Environmental Impact ◽  
Soil Carbon ◽  
Overland Flow ◽  
South Australia ◽  
Farming Practices ◽  
Organic C ◽  
Dissolved Organic C ◽  
Texture Contrast ◽  
Minimal Environmental Impact ◽  
Dissolved Form

Runoff (overland flow and A/B horizon interflow) from 2 grazed dairy pastures at Flaxley, South Australia, accounted for <15% of April{October rainfall in 1996; 88{96% of runoff was overland flow. A range of chemicals, including carbon (C), phosphorus (P), and sulfur (S), was measured in runoff As much as 2·3 kg P/ha, 10·7 kg/ha of total dissolved C, and 1·8 kg S/ha was lost from the catchments in that year. Loads of other chemicals ranged from 0·6 g/ha (boron) to 39·8 kg/ha (aluminium). Over 92% of P, 76% of total dissolved C, and 93% of S was lost in overland flow. Between 50% and 60% of P, and 60% and 85% of S, was in the dissolved form; 64-96% of total dissolved C was dissolved organic C. Other chemicals varied from 0% (aluminium) to 97% (sodium) as the dissolved form. Relatively high losses of P and dissolved organic C are important to a dairy industry which is under increasing pressure to demonstrate minimal environmental impact from farming practices.

Water quality of gully drainage from texture-contrast soils in the Adelaide Hills in low rainfall years

Soil Research ◽  
2000 ◽  
Vol 38 (5) ◽  
pp. 959 ◽  
Author(s):  
J. W. Cox ◽  
R. Ashley
Keyword(s):  
Overland Flow ◽  
Environmental Concern ◽  
South Australia ◽  
Drainage Water ◽  
Agricultural Catchments ◽  
Environmental Guidelines ◽  
Texture Contrast ◽  
Carbon Concentrations ◽  
Dissolved Form

The volume and quality of drainage water in a gully cutting through a series of waterlogged, saline, sodic, and sulfidic Xeralfs in the Adelaide Hills, South Australia, was studied over 3 years. This was done to gain a better perspective of the relative quantities of contaminants being exported from agricultural catchments in low rainfall agricultural environments. It was found that in low rainfall years, when little overland flow occurs and gully flow is predominantly groundwater discharge and throughflow, loads in the drainage gully were up to 41 kg/ha.year of sodium and 2 kg/ha.year of sulfur. Losses of sulfur, magnesium, and calcium followed a similar trend to sodium losses and could be predicted with significant accuracy. The losses of phosphorus (5–7 g/ha.year) and nitrate (<2 g/ha.year) were less predictable. Phosphorus concentrations were of environmental concern each year whereas nitrate concentrations were only above environmental guidelines in the driest year. All phosphorus in the gully drainage was transported in the dissolved form. Dissolved organic carbon concentrations were usually >26 mg/L and will be costly to treat if used for public water supply.

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.

Clarify the dependency of controlling factors in DOC transport in small mountainous rivers by redundancy analysis

2020 ◽  
Author(s):  
En-Ru Liu ◽  
Yu-Ting Shih ◽  
Li-Chin Lee
Keyword(s):  
Organic Carbon ◽  
Human Activities ◽  
Redundancy Analysis ◽  
Controlling Factors ◽  
Catchment Management ◽  
Catchment Scale ◽  
Ungauged Catchments ◽  
Doc Export ◽  
Explained Variance ◽  
Small Mountainous Rivers

&lt;p&gt;Dissolved organic carbon (DOC) serves as one of the major energy sources in aquatic ecosystems, which is an important pathway connecting terrestrial and marine carbon reservoirs. DOC transport at catchment scale is recognized as being regulated by runoff, slope, soil organic carbon (SOC), biome, and wetland proportion; however, the controls in subtropical small mountainous rivers (SMRs) is rarely discovered before. This study investigated DOC export in 19 catchments in northern Taiwan supplemented with landscape and land use dataset to characterize the controlling factors of DOC transport. Meanwhile, the principle component analysis (PCA) and redundancy analysis (RDA) are applied to untangle the dependence of the controlling factors. Results showed that DOC concentration in Taiwan is very low at approx. 0.8 mg L&lt;sup&gt;-1&lt;/sup&gt;, yet the annual DOC yields of the 19 catchments is around 25.23 kg ha&lt;sup&gt;-1&lt;/sup&gt; yr&lt;sup&gt;-1&lt;/sup&gt;, which is much higher than the global mean (14.4&amp;#8211;19.3 kg-C ha&lt;sup&gt;-1&lt;/sup&gt; yr&lt;sup&gt;-1&lt;/sup&gt;). PCA and RDA shows that the human activities and landscape can explain 87% and 77% of the explained variance, yet runoff play an independent role in DOC transport. &amp;#160;Excluding the overlap, human activities and landscape only accounts for 15 % and 5% of the explained variance, respectively. The overlap between the two components are as high as 72%, indicating the two components could not be separated subjectively. Conclusively, DOC export is mostly dominated by human activities and landscape together, which suggests that they should be considered simultaneously. Besides, DOC yield is positively correlated with streamflow and SOC, but negatively correlated with slope gradient. Our study suggests that interpretation of spatial variation in DOC export should address the overlap between human activities and landscape, which can help predicting the ungauged catchments in catchment management.&lt;/p&gt;

Effect of aggregate breakdown on the unevenly enriched organic carbon process in sediments under a rain-induced overland flow

2020 ◽  
Vol 204 ◽  
pp. 104752
Author(s):  
L. Liu ◽  
Z.W. Li ◽  
Z.J. Li ◽  
E.F. Liu ◽  
X.D. Nie ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Overland Flow ◽  
Aggregate Breakdown

scholarly journals Australian net (1950s–1990) soil organic carbon erosion: implications for CO<sub>2</sub> emission and land–atmosphere modelling

2014 ◽  
Vol 11 (18) ◽  
pp. 5235-5244 ◽  
Author(s):  
A. Chappell ◽  
N. P. Webb ◽  
R. A. Viscarra Rossel ◽  
E. Bui
Keyword(s):  
Soil Erosion ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Land Surface ◽  
Total Carbon ◽  
Catchment Scale ◽  
European Settlement ◽  
Surface Models ◽  
Management Context ◽  
Land Use And Management

Abstract. The debate remains unresolved about soil erosion substantially offsetting fossil fuel emissions and acting as an important source or sink of CO2. There is little historical land use and management context to this debate, which is central to Australia's recent past of European settlement, agricultural expansion and agriculturally-induced soil erosion. We use "catchment" scale (∼25 km2) estimates of 137Cs-derived net (1950s–1990) soil redistribution of all processes (wind, water and tillage) to calculate the net soil organic carbon (SOC) redistribution across Australia. We approximate the selective removal of SOC at net eroding locations and SOC enrichment of transported sediment and net depositional locations. We map net (1950s–1990) SOC redistribution across Australia and estimate erosion by all processes to be ∼4 Tg SOC yr−1, which represents a loss of ∼2% of the total carbon stock (0–10 cm) of Australia. Assuming this net SOC loss is mineralised, the flux (∼15 Tg CO2-equivalents yr−1) represents an omitted 12% of CO2-equivalent emissions from all carbon pools in Australia. Although a small source of uncertainty in the Australian carbon budget, the mass flux interacts with energy and water fluxes, and its omission from land surface models likely creates more uncertainty than has been previously recognised.

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