Mapping and comparing the distribution of soil carbon under cropping and grazing management practices in Narrabri, north-west New South Wales

Soil Research ◽  
2010 ◽  
Vol 48 (3) ◽  
pp. 248 ◽  
Author(s):  
Matthew Miklos ◽  
Michael G. Short ◽  
Alex B. McBratney ◽  
Budiman Minasny

The reliable assessment of soil carbon stock is of key importance for soil conservation and mitigation strategies related to reducing atmospheric carbon. Measuring and monitoring soil carbon is complex because carbon pools cycle and rates of carbon sequestration vary across the landscape due to climate, soil type, and management practices. A new methodology has been developed and applied to make an assessment of the distribution of total, organic, and inorganic carbon at a grains research and grazing property in northern New South Wales at a high spatial resolution. In this study, baseline soil carbon maps were created using fine resolution, geo-referenced, proximal sensor data. Coupled with a digital elevation model and secondary terrain attributes, all of the data layers were combined by k-means clustering to develop a stratified random soil sampling scheme for the survey area. Soil samples taken at 0.15-m increments to a depth of 1 m were scanned with a mid-infrared spectrometer, which was calibrated using a proportion of the samples that were analysed in a laboratory for total carbon and inorganic carbon content. This combination of new methodologies and technologies has the potential to provide large volumes of reliable, fine resolution and timely data required to make baseline assessments, mapping, monitoring, and verification possible. This method has the potential to make soil carbon management and trading at the farm-scale possible by quantifying the carbon stock to a depth of 1 m and at a high spatial resolution.

Soil Research ◽  
2013 ◽  
Vol 51 (8) ◽  
pp. 680 ◽  
Author(s):  
M. K. McLeod ◽  
G. D. Schwenke ◽  
A. L. Cowie ◽  
S. Harden

Reduced carbon stock levels in Australian soil due to cropping provide a significant opportunity for carbon sequestration, and the recent initiative to consider soil carbon in domestic emissions trading requires a scientific assessment of soil carbon levels under a range of cropping soil management practices. Some of the previous research in southern and western New South Wales (NSW) showed that the rate of carbon decline in cropping soils is slowed under minimum tillage when the stubble is also retained. However, such comparison is rare in the NSW North-West Slopes and Plains region, particularly on the red soils (Chromosols) which are one of the major soil types in the region. We surveyed 50 dryland Chromosols, 72 dryland Vertosols, and 25 irrigated Vertosols on commercial farms across this region to examine the effects of conventional tillage, minimum tillage, and irrigation on total soil organic carbon. Samples of 0.1 m segments to 0.3 m depth were analysed for total organic carbon and other soil properties. Mid-infrared scans were used to predict the particulate, humus, and resistant soil organic carbon fractions. Bulk density was used to calculate total organic carbon stock for each segment, and equivalent soil mass (ESM) for 0–0.3 m. In Vertosols, for 0–0.3 m ESM, total organic carbon and particulate organic carbon were not different between management practices, whereas humic organic carbon and resistant organic carbon were consistently lower under conventional tillage. However, in 0–0.1 m, total organic carbon was greater under minimum tillage (15.2 Mg ha–1) than conventional tillage (11.9 Mg ha–1) or irrigation (12.0 Mg ha–1), reflecting less soil surface disturbance under minimum tillage. In Chromosols, only total organic carbon was higher under minimum tillage than conventional tillage in the 0–0.3 m ESM (39.8 v. 33.5 Mg ha–1) and in 0–0.1 m (19.7 v. 16.9 Mg ha–1). The strong influences of rainfall, temperature, bulk density, texture, and management history on soil carbon stocks suggested that these environmental and management factors require further consideration when gauging soil carbon sequestration potential under current and novel tillage practices in key regional locations.


Soil Research ◽  
2009 ◽  
Vol 47 (3) ◽  
pp. 340
Author(s):  
B. Kelly ◽  
C. Allan ◽  
B. P. Wilson

'Soil health' programs and projects in Australia's agricultural districts are designed to influence farmers' management behaviours, usually to produce better outcomes for production, conservation, and sustainability. These programs usually examine soil management practices from a soil science perspective, but how soils are understood by farmers, and how that understanding informs their farm management decisions, is poorly documented. The research presented in this paper sought to better understand how dryland farmers in the Billabong catchment of southern New South Wales use soil indicators to inform their management decisions. Thematic content analysis of transcripts of semi-structured, face-to-face interviews with farmers suggest several themes that have implications for soil scientists and other professionals wishing to promote soil health in the dryland farming regions of south-eastern Australia. In particular, all soil indicators, including those related to soil 'health', need to relate to some clear, practical use to farmers if they are to be used in farm decision making. This research highlights a reliance of the participants of this research on agronomists. Reliance on agronomists for soil management decisions may result in increasing loss of connectivity between farmers and their land. If this reflects a wider trend, soil health projects may need to consider where best to direct their capacity-building activities, and/or how to re-empower individual farmers.


1994 ◽  
Vol 34 (7) ◽  
pp. 921 ◽  
Author(s):  
DC Godwin ◽  
WS Meyer ◽  
U Singh

Evidence exists that night temperatures <18�C immediately preceding flowering in rice crops can adversely affect floret fertility and, hence, yields. It has been suggested that sterility induced by low temperature is also influenced by floodwater depth and nitrogen (N) rate. In southern New South Wales, low night-time temperatures are believed to be a major constraint to the achievement of consistently high yields. The availability of a comprehensive model of rice growth and yield that is sensitive to this constraint would aid the development of better management practices. CERES RICE is a comprehensive model that simulates the phasic development of a rice crop, the growth of its leaves, stems, roots, and panicles, and their response to weather. It also simulates the water and N balances of the crop and the effects of stresses of water and N on the yield-forming processes. The model has been extensively tested in many rice-growing systems in both tropical and temperate environments. However, the original model was unable to simulate the level of chilling injury evident from yield data from southern New South Wales. This paper reports modifications made in the model to simulate these effects and the evaluation of the model in environments of low night temperature. Inclusion of the chilling injury effect greatly improved the accuracy of estimated yields from treatments in an extensive field experiment. However, additional testing with a wider range of data sets is needed to confirm the international applicability of the modifications.


2012 ◽  
Vol 52 (7) ◽  
pp. 675 ◽  
Author(s):  
R. D. Bush ◽  
R. Barnett ◽  
I. J. Links ◽  
P. A. Windsor

The prevalence of Caseous lymphadenitis (CLA) in Australia was estimated to be 5.2% using 2009 abattoir surveillance data from all States supplied by Animal Health Australia involving 5029 lines comprising 1 339 463 sheep. This is a decrease from the 26% estimated in a similar study in 1995. There was a significant difference (P < 0.001) in CLA prevalence between all states except Tasmania and Victoria (P = 0.75) with prevalences of 12.8 and 12.9%, respectively. Western Australia recorded the lowest prevalence with 1.0%. The average CLA prevalence for New South Wales was 5.3% and within three surveyed Livestock Health and Pest Authority regions (Tablelands, Central North and Central West) was 2.9, 4.9 and 4.4%, respectively. The attitude of the majority of producers surveyed in these three Livestock Health and Pest Authority areas was that CLA was of little or no significance (75%) but were aware of the need for CLA control with ~68% using 6-in-1 vaccine, though only 39.9% as recommended. It appears that the prolonged use of CLA vaccination has been successful in reducing the prevalence of CLA across Australia and particularly in New South Wales. Further improvements in communication of information on preventative management practices associated with lice control, importance of using an approved vaccination program, plus increasing producers’ awareness of the importance of CLA control, are indicated.


Soil Research ◽  
2005 ◽  
Vol 43 (1) ◽  
pp. 21 ◽  
Author(s):  
Rick Young ◽  
Brian R Wilson ◽  
Malem McLeod ◽  
Clair Alston

The organic carbon stock in biomass and soil profiles sampled from nearby paddocks with different land-use histories was estimated at 7 sites in the upper Liverpool Plains catchment and the Manilla district of north-western New South Wales, Australia. The distribution of soil carbon concentrations over a depth of 2 m was significantly affected by site and land use. Continuous cultivation and cropping over ≥20 years significantly depleted carbon concentrations compared with grassy woodlands in the surface 0.20 m at all sites and to a depth of 0.60 m at 3 sites. Depth of sampling (0–0.20 v. 0–1.0 m) significantly affected the differences between land uses at most sites regarding estimates of the stock of soil carbon. These results show that differences in soil carbon concentrations and stock size do not remain constant with depth between contrasting land uses. However, comparisons between land uses of the total amount of carbon stored were dominated by the number of trees per ha and the size of the trees in grassy woodlands. The implications of these results for carbon accounting are discussed.


1990 ◽  
Vol 12 (2) ◽  
pp. 67 ◽  
Author(s):  
ND Macleod

Uany pastoral leases in western New South Wales are too small to ensure that viable pastoral enterprisu will persist in the medium to longer term. Apart from attendant welfare problems for leaseholders and their dependants, there is some evidence that this has exacerbated overgrazing problems which creates undesirable and potentially irreversible degradation of vegetation and soil resources. Arguably, the small size problem has sufficiently weakened the economic welfare of many lessees to make private acquisition of additional areas andl or adoption of conservation oriented management practices non-economic. The future scenario is then one of greater public involvement in property adjustment measures; or a growing population of non-viable pastoral enterprises with its attendant efficiency, welfare and resource conservation problems. The paper examines trends in property enterprise size, structure and concentration and the existence and extent of size economies for wool and livestock production in western New South Wales. Several issues are addressed concerning the economic viability of pastoral properties and several public policy prescriptions are presented for addressing the sizehiability problem.


Soil Research ◽  
2009 ◽  
Vol 47 (2) ◽  
pp. 234 ◽  
Author(s):  
B. Kelly ◽  
C. Allan ◽  
B. P. Wilson

‘Soil health’ programs and projects in Australia’s agricultural districts are designed to influence farmers’ management behaviours, usually to produce better outcomes for production, conservation, and sustainability. These programs usually examine soil management practices from a soil science perspective, but how soils are understood by farmers, and how that understanding informs their farm management decisions, is poorly documented. The research presented in this paper sought to better understand how dryland farmers in the Billabong catchment of southern New South Wales use soil indicators to inform their management decisions. Thematic content analysis of transcripts of semi-structured, face-to-face interviews with farmers suggest several themes that have implications for soil scientists and other professionals wishing to promote soil health in the dryland farming regions of south-eastern Australia. In particular, all soil indicators, including those related to soil ‘health’, need to relate to some clear, practical use to farmers if they are to be used in farm decision making. This research highlights a reliance of the participants of this research on agronomists. Reliance on agronomists for soil management decisions may result in increasing loss of connectivity between farmers and their land. If this reflects a wider trend, soil health projects may need to consider where best to direct their capacity-building activities, and/or how to re-empower individual farmers.


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