References and Glossary


Acid(ic) soil: Soils that have a pHCa of 5.4 or less
Arable land:  land that is able to be cultivated 
Chlorosis: Abnormal yellowing of plants.
Effective cation exchange capacity (ECEC): The sum of the values in a soil analysis of exchangeable cations (calcium, magnesium, sodium, potassium, manganese and aluminium). The unit of measurement is cmol(+)/kg (previously meq/100 g).
Exchangeable cations: Exchangeable cations are positively charged ions that are loosely bound to negatively charged clay particles and organic matter in soil. The unit of measurement is cmol (+)/kg (previously meq/100 g).
Lime: The name used to describe any of several liming materials, including agricultural limestone and dolomite. In the building industry “lime” refers to calcium hydroxide (slaked lime)
Necrosis: Death of parts of plants, giving a brown shrivelled appearance.
Nitrification: The transformation of ammonium to nitrate by microbes.
Soil pH measurement: Soil pH is measured in two ways in Australia.
1. Mixed and shaken 1:5 soil: 0.01 M CaCl2 (pHCa).
2. Mixed and shaken 1:5 soil: water (pHw).
pHCa gives pH values on average 0.5 to 0.8 lower, but with less seasonal variation, than pHw. While most commercial soil testing laboratories use the CaCl2 method, most field pH testing kits and some laboratories use the water method
Soil solution: the water in the soil and its dissolved substances, gases, minerals and organic matter. It is sometimes called the liquid phase. 
Valid sampling strategy: A program of representative soil sample collection and analysis that has a clearly defined purpose for a given area to of interest. A sound strategy will outline when to sample, how many samples to collect, how many different zones have been identified in the area of interest and which type of analysis are appropriate for a given purpose. For more info on this see:

  • A guide for fit for purpose soil sampling by C Gourley and D Weaver
  • GRDC’s crop nutrition factsheets: Soil testing for crop nutrition southern region or northern region


1. Hajkowicz & Young, 2005. Costing yield loss from acidity, sodicity and dryland salinity to Australian agriculture. land Deg and Dev. 16(5) 417-433.

2. Thomas G. Orton  Thilak Mallawaarachchi  Matthew J. Pringle  Neal W. Menzies  Ram C. Dalal  Peter M. Kopittke  Ross Searle  Zvi Hochman  Yash P. Dang 2018.  Quantifying the economic impact of soil constraints on Australian agriculture: A case‐study of wheat. Land Deg and Dev. 29(11) 3866-3875

3.  Metcalfe D, Bui E (2016). Land: Soil: Salinity and acidification. In: Australia state of the environment 2016, Australian Government Department of the Environment and Energy, Canberra,

4.  10 Soil condition in NSW state of the environment 2015 pp 85-93 accessed on 17/10/18

5. Gray J 2018 . Digital soil mapping of key soil properties over NSW, version 1.2. Technical Report, NSW Office of Environment and Heritage, Sydney.

6.  Belinda Hackney, Brian Dear, Mark Peoples, Gabrielle Dyce and Craig Rodham. 2008 Herbage production, nitrogen fixation and water use efficiency of ten annual pasture legumes grown with and without lime on an acid soil in Proceedings of 14th Agronomy Conference 2008

7. Guangdi D.Li, Mark K.Conyers, Keith R.Helyar, Chris J.Lisle, Graeme J.Poile, Brian R.Cullis 2019  Long-term surface application of lime ameliorates subsurface soil acidity in the mixed farming zone of south-eastern Australia. Geoderma 338, 236-246