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

We examined soil organic carbon (SOC) concentration (mgg -1 ) and total organic carbon (TOC) stock (Mgha -1 to 30cm 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 (0.1-0.3m) 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.

[1]  K. Chan,et al.  Soil carbon storage potential under perennial pastures in the mid-north coast of New South Wales, Australia , 2010 .

[2]  D. Liu,et al.  Soil carbon stocks under different pastures and pasture management in the higher rainfall areas of south-eastern Australia , 2010 .

[3]  B. Wilson,et al.  Soil carbon and related soil properties along a soil type and land‐use intensity gradient, New South Wales, Australia , 2011 .

[4]  L. Janik,et al.  Characterization and analysis of soils using mid-infrared partial least-squares .2. Correlations with some laboratory data , 1995 .

[5]  J. Baldock.  Composition and Cycling of Organic Carbon in Soil , 2007 .

[6]  T. Koen,et al.  Variations in soil organic carbon for two soil types and six land uses in the Murray Catchment, New South Wales, Australia , 2013 .

[7]  J. Grace.  Understanding and managing the global carbon cycle , 2004 .

[8]  N. Batjes,et al.  Total carbon and nitrogen in the soils of the world , 1996 .

[9]  B. Wesemael,et al.  Changes in organic carbon distribution with depth in agricultural soils in northern Belgium, 1960–2006 , 2009 .

[10]  G. Griffith,et al.  Livestock Farming Systems in the Northern Tablelands of NSW: An Economic Analysis , 2003 .

[11]  B. Wilson,et al.  Land-use effects on soil properties on the north-western slopes of New South Wales: Implications for soil condition assessment , 2008 .

[12]  B. Wilson,et al.  Accumulation of soil carbon under zero tillage cropping and perennial vegetation on the Liverpool Plains, eastern Australia , 2009 .

[13]  L. Janik,et al.  Characterization and analysis of soils using mid-infrared partial least-squares .1. Correlations with XRF-determined major-element composition , 1995 .

[14]  R. Lal,et al.  Soil Carbon Sequestration Impacts on Global Climate Change and Food Security , 2004, Science.

[15]  Jeff Baldock,et al.  Soil carbon sequestration potential: a review for Australian agriculture. , 2009 .

[16]  Richard T. Conant,et al.  Soil organic carbon in managed pastures of the southeastern United States of America. , 2010 .

[17]  Mark Conyers,et al.  Soil carbon dynamics under different cropping and pasture management in temperate Australia: Results of three long-term experiments , 2011 .

[18]  Sébastien Barot,et al.  Stability of organic carbon in deep soil layers controlled by fresh carbon supply , 2007, Nature.

[19]  R. Greene,et al.  Opportunities to sequester carbon in soil: Management of perennial pastures , 2012 .

[20]  K. Paustian,et al.  Stabilization mechanisms of soil organic matter: Implications for C-saturation of soils , 2002, Plant and Soil.

[21]  K. Paustian,et al.  GRASSLAND MANAGEMENT AND CONVERSION INTO GRASSLAND: EFFECTS ON SOIL CARBON , 2001 .

[22]  J. Baldock,et al.  SOIL TEXTURE EFFECTS ON DECOMPOSITION AND SOIL CARBON STORAGE , 2001 .

[23]  Rattan Lal,et al.  Soil Carbon Sequestration and the Greenhouse Effect , 2001 .

[24]  Brian Murphy,et al.  Relationship between environmental and land-use variables on soil carbon levels at the regional scale in central New South Wales, Australia , 2013 .

[25]  National Soil Carbon Research Programme: Field and Laboratory Methodologies , 2011 .

[26]  R. B. Jackson,et al.  THE VERTICAL DISTRIBUTION OF SOIL ORGANIC CARBON AND ITS RELATION TO CLIMATE AND VEGETATION , 2000 .

[27]  R. Houghton,et al.  The Contemporary Carbon Cycle , 2014 .

[28]  R. Isbell.  Australian Soil Classification , 1996 .

[29]  Petra Marschner,et al.  Nutrient Cycling in Terrestrial Ecosystems , 2007 .

[30]  R. S. Swift.  SEQUESTRATION OF CARBON BY SOIL , 2001 .

[31]  Stephen Joseph,et al.  Using poultry litter biochars as soil amendments , 2008 .

[32]  Brian Wilson,et al.  Measurement and estimation of land-use effects on soil carbon and related properties for soil monitoring: a study on a basalt landscape of northern New South Wales, Australia , 2010 .

[33]  J. Baldock,et al.  Soils and climate change: potential impacts on carbon stocks and greenhouse gas emissions, and future research for Australian agriculture , 2012, Crop and Pasture Science.

[34]  L. Janik,et al.  Non-living soil organic matter: what do we know about it? , 1998 .

[35]  A. Oates,et al.  Soil carbon fractions and relationship to soil quality under different tillage and stubble management , 2002 .

[36]  B. Wilson,et al.  Carbon storage in the soils and vegetation of contrasting land uses in northern New South Wales, Australia , 2005 .

[37]  G. Gee,et al.  Particle-size Analysis , 2018, SSSA Book Series.

[38]  C. Chenu,et al.  Relative importance of sorption versus aggregation for organic matter storage in subsoil horizons of two contrasting soils , 2010 .

[39]  K. Chan.  Soil particulate organic carbon under different land use and management , 2001 .

[40]  Dinesh Kumar,et al.  Integrated Crop Management , 2008 .

[41]  George E. Rayment,et al.  Soil Chemical Methods – Australasia , 2011 .