Spatial variation in soil organic carbon and nitrogen at two field sites under crop and pasture rotations in southern New South Wales, Australia

Soil Research ◽  
2018 ◽  
Vol 56 (8) ◽  
pp. 780 ◽  
Author(s):  
Mark Conyers ◽  
Beverley Orchard ◽  
Susan Orgill ◽  
Albert Oates ◽  
Graeme Poile ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Spatial Variation ◽  
New South ◽  
New South Wales ◽  
Wagga Wagga ◽  
Soil Cores ◽  
South Wales ◽  
Sampling Protocols ◽  
The Mean

Estimating the likely variance in soil organic carbon (OC) at the scale of farm fields or smaller monitoring areas is necessary for developing sampling protocols that allow temporal change to be detected. Given the relatively low anticipated soil OC sequestration rates (<0.5 Mg/ha.0.30 m/year) for dryland agriculture it is important that sampling strategies are designed to reduce any cumulative errors associated with measuring soil OC. The first purpose of this study was to evaluate the spatial variation in soil OC and nitrogen (N), in soil layers to 1.50 m depth at two monitoring sites (Wagga Wagga and Yerong Creek, 0.5 ha each) in southern New South Wales, Australia, where crop and pasture rotations are practiced. Four variogram models were tested (linear, spherical, Gaussian and exponential); however, no single model dominated across sites or depths for OC or N. At both sites, the range was smallest in surface soil, and on a scale suggesting that sowing rows (stubble) may dominate the pattern of spatial dependence, whereas the longer ranges appeared to be associated with horizon boundaries. The second purpose of the study was to obtain an estimate of the population mean with 1%, 5% and 10% levels of precision using the calculated variance. The number of soil cores required for a 1% precision in estimation of the mean soil OC or N was impractical at most depths (>500 per ha). About 30 soil cores per composite sample to 1.50 m depth, each core being at least 10 m apart, would ensure at least an average of 10% precision in the estimation of the mean soil OC at these two sites, which represent the agriculture of the region.

Driving factors of soil organic carbon fractions over New South Wales, Australia

Geoderma ◽  
2019 ◽  
Vol 353 ◽  
pp. 213-226 ◽  
Author(s):  
Jonathan Gray ◽  
Senani Karunaratne ◽  
Thomas Bishop ◽  
Brian Wilson ◽  
Manoharan Veeragathipillai
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
New South ◽  
New South Wales ◽  
Driving Factors ◽  
Carbon Fractions ◽  
South Wales ◽  
Organic Carbon Fractions ◽  
Soil Organic Carbon Fractions

Should we manage soil organic carbon in Vertosols in the northern grains region of Australia?

2003 ◽  
Vol 43 (3) ◽  
pp. 261 ◽  
Author(s):  
R. J. Farquharson ◽  
G. D. Schwenke ◽  
J. D. Mullen
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
New South ◽  
New South Wales ◽  
Soil Health ◽  
Organic Carbon Content ◽  
Continuous Cropping ◽  
South Wales ◽  
On Farm ◽  
Carbon Concentrations

Two issues prompted this paper. The first was the measured soil organic carbon decline in fertile northern Australian soils under continual cropping using traditional management practices. We wanted to see whether it was theoretically possible to maintain or improve soil organic carbon concentrations with modern management recommendations. The second was the debate about use of sustainability indicators for on-farm management, so we looked at soil organic carbon as a potential indicator of soil health and investigated whether it was useful in making on-farm crop decisions. The analytical results indicated first that theoretically the observed decline in soil organic carbon concentrations in some northern cracking clay soils can be halted and reversed under continuous cropping sequences by using best practice management. Second, the results and associated discussion give some support to the use of soil organic carbon as a sustainability indicator for soil health. There was a consistent correlation between crop input decisions (fertilisation, stubble management, tillage), outputs (yield and profits) and outcomes (change in soil organic carbon content) in the short and longer term. And this relationship depended to some extent on whether the existing soil organic carbon status was low, medium or high. A stock dynamics relationship is one where the change in a stock (such as soil organic carbon) through time is related not only to the management decisions made and other random influences (such as climatic effects), but also to the concentration or level of the stock itself in a previous time period. Against such a requirement, soil organic carbon was found to be a reasonable measure. However, the inaccuracy in measuring soil organic carbon in the paddock mitigates the potential benefit shown in this analysis of using soil organic carbon as a sustainability indicator.These results are based on a simulation model (APSIM) calibrated for a cracking clay (Vertosol) soil typical of much of the intensively-cropped slopes and plains region of northern New South Wales and southern Queensland, and need to be interpreted in this light. There are large areas of such soils in north-western New South Wales; however, many of these experience lower rainfalls and plant-available soil water capacities than in this case, and the importance of these characteristics must also be considered.

Land-use and historical management effects on soil organic carbon in grazing systems on the Northern Tablelands of New South Wales

Soil Research ◽  
2013 ◽  
Vol 51 (8) ◽  
pp. 668 ◽  
Author(s):  
Brian R. Wilson ◽  
Vanessa E. Lonergan
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Surface Soil ◽  
Soil Depth ◽  
New South ◽  
New South Wales ◽  
Soil Layers ◽  
South Wales ◽  
Native Pasture ◽  
Historical Management

We examined soil organic carbon (SOC) concentration (mg g–1) and total organic carbon (TOC) stock (Mg ha–1 to 30 cm soil depth) in three pasture systems in northern New South Wales: improved pasture, native pasture, and lightly wooded pasture, at two sampling times (2009 and 2011). No significant difference was found in SOC or TOC between sample times, suggesting that under the conditions we examined, neither 2 years nor an intervening significant rainfall event was sufficient to change the quantity or our capacity to detect SOC, and neither represented a barrier to soil carbon accounting. Low fertility, lightly wooded pastures had a slightly but significantly lower SOC concentration, particularly in the surface soil layers. However, no significant differences in TOC were detected between the three pasture systems studied, and from a carbon estimation perspective, they represent one, single dataset. A wide range in TOC values existed within the dataset that could not be explained by environmental factors. The TOC was weakly but significantly correlated with soil nitrogen and phosphorus, but a more significant pattern seemed to be the association of high TOC with proportionally larger subsoil (0.1–0.3 m) organic carbon storage. This we attribute to historical, long-term rather than contemporary management. Of the SOC fractions, particulate organic carbon (POC) dominated in the surface layers but diminished with depth, whereas the proportion of humic carbon (HUM) and resistant organic carbon (ROC) increased with soil depth. The POC did not differ between the pasture systems but native pasture had larger quantities of HUM and ROC, particularly in the surface soil layers, suggesting that this pasture system tends to accumulate organic carbon in more resistant forms, presumably because of litter input quality and historical management.

Variations in soil organic carbon for two soil types and six land uses in the Murray Catchment, New South Wales, Australia

Soil Research ◽  
2013 ◽  
Vol 51 (8) ◽  
pp. 631 ◽  
Author(s):  
M. C. Davy ◽  
T. B. Koen
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
New South ◽  
New South Wales ◽  
Agricultural Landscapes ◽  
Soil Types ◽  
Land Uses ◽  
South Wales ◽  
Physico Chemical ◽  
Soc Stocks

The aim of this study was to investigate variations in soil organic carbon (SOC) for two soil types and six common land uses in the New South Wales Murray Catchment and to explore the factors influencing those variations. Samples were collected from 100 sites on duplex soils (Ustalfs) of the Slopes region, and 100 sites on red-brown earths (Xeralfs) of the Plains region. Stocks of SOC (0–30 cm) across the study area ranged between 22.3 and 86.0 t ha–1, with means (± s.e.) of 42.0 ± 1.3 and 37.9 ± 0.8 t ha–1 for the Slopes and Plains regions, respectively. Higher SOC stocks were present in pasture-dominated land uses compared with mixed cropping in the Slopes region, with particularly high stocks found in pastures at positions on a slope of 7–10%. No significant differences in SOC stocks were identified between land-use groups (pastures or cropping) in the Plains region (<500-mm rainfall zone). Significant correlations were found between SOC and a range of climatic, topographical, and soil physico-chemical variables at both the catchment and sub-regional scale. Soil physico-chemical and topographical factors play an important role in explaining SOC variation and should be incorporated into models that aim to predict SOC sequestration across agricultural landscapes.

Removing Grazing Pressure from a Native Pasture Decreases Soil Organic Carbon in Southern New South Wales, Australia

2016 ◽  
Vol 29 (2) ◽  
pp. 274-283 ◽  
Author(s):  
Susan Elizabeth Orgill ◽  
Jason Robert Condon ◽  
Mark Kenneth Conyers ◽  
Stephen Grant Morris ◽  
Douglas John Alcock ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
New South ◽  
New South Wales ◽  
Grazing Pressure ◽  
South Wales ◽  
Native Pasture

The breeding behaviour of the endangered regent honeyeater, Xanthomyza phrygia, near Armidale, New South Wales

1998 ◽  
Vol 46 (2) ◽  
pp. 153 ◽  
Author(s):  
Damon L. Oliver
Keyword(s):  
New South ◽  
New South Wales ◽  
Population Level ◽  
Similar Rate ◽  
Nest Construction ◽  
Aggressive Interactions ◽  
Breeding Behaviour ◽  
South Wales ◽  
The Mean ◽  
Breeding Seasons

The regent honeyea ter, Xanthomyza phrygia, is an endangered woodland bird whose range and population size have decreased in the last thirty years. Suggested reasons for this decline include abnormal breeding behaviour, poor reproductive output, and excessive inter- and intra-specific aggression. This study investigated the breeding behaviour and aggressive interactions of regent honeyeaters during the nest construction, incubation, nestling, and fledgling stages in two consecutive breeding seasons in the Bundarra–Barraba region near Armidale, New South Wales. The female was entirely responsible for nest construction and incubation, which is typical of many honeyeaters. Both parents fed the nestlings, and at a similar rate, although only the female brooded chicks on the nest. Both parents fed the fledglings. The mean frequency at which nestlings (23 times per hour) and fledglings (29 times per hour) were fed is the highest published rate of any non-cooperative honeyeater. Breeding males were involved in significantly more aggressive interactions with conspecifics and other nectarivores than were females, although the overall percentage of day-time spent in aggression for both sexes was low (2.5%). It appears that abnormal breeding behaviour, poor reproductive effort, or excessive aggression are not experienced by this species in northern New South Wales, and that other factors are likely to be responsible for its current low population level.

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