More Online Information
Queensland Soil Types
EnviroNorth, Tropical Savannas Knowledge in Schools
Look for regional gardening and environmental groups (who might be able to supply information on local soils) on the Regional pages.
Article in The Native Gardener, Newsletter of the Society for Growing Australian Plants Townsville Branch Inc. (PDF)
Note that commercial products, regulations, plants and soil types vary from place to place, so some information in links may not apply where you live.
A number of factsheets can be downloaded from this page. Queensland Dept Environment & Resource Management
Soil health for vegetable production in Australia
This soil science manual, which should be of interest to serious gardeners and students of horticulture as well as farmers, can be downloaded in PDF formfrom this page. Department of Employment, Economic Development and Innovation
What is Soil?
Basic overview. Department of Primary Industries Victoria
State of Victoria, Department of Primary Industries, Victoria
Soil biology basics
factsheets on a variety of topics available from this page. NSW department of Primary Industries
Soil Ecology and Restoration Group, San Diego State University, USA
Water penetration and retention
Does gypsum improve clay soils?
There's a widespread misconception, even amongst horticulture professionals, that gypsum can improve the structure of every clay soil. Check out the following links:
pH (Acididity or Alkalinity)
These links have been moved to a new page: Soil pH
Organic Matter, Carbon
See also articles on Humus and Cation Exchange Capacity above
Soil factors such as pH and cation exchange capacity will affect the behaviour of nutrients with the soil and availabitlity to plants. The nutrients themselves are covered in more detail on the Plant nutrition and nutrient deficiencies
The Myth of Soil Amendments Part II Will adding sand improve the texture of a clay soil? Washington State University (PDF)
Manufacturers and distributors of soil conditioners and amendments available in Qld are invited to advertise on this page. For example: composts including treated wastes, wetting agents, pH adjustment, water storage additives (granules, gels), additives for drainage and porosity, flocculation agents. More information about advertising.
More about mulches and mulching practice here: Mulches
Hydroseeding goes organic
Mexican researchers are developing an organic hydroseeding techniques to stabilise sloping roadsides that is actually better than alternatives employing artificial polymers, adhesives and fertilisers. Components of the new technique include mycorrhizae to encourage soil aggregation and an adhesive made from the nopal cactus. Gardens used to reduce landslides (September 2013)
Soil contamination risks in urban gardens
One of the risks of vegetable gardening in urban areas is soil contaminated by toxins. Soil tests may indicate problems, but researchers in Detroit evaluating sampling strategies in a garden plot found that some of the methods failed to detect a lead "hotspot". They suggest that standard sampling procedures be reassessed, and that if possible garden planners check historical records to ascertain what activities the land was previously used for. Source: Detecting Lead Hotspots in Urban Gardens Requires Different Sampling Strategies according to Wayne State research (June 2013)
Bacteria build soil
Research suggests that a significant proportion of soil organic matter may not derive from plant material directly, but from the remains of the soil microflora that feed on it. Bacterial cell wall fragments, resistant to further decay, thus contribute to the long-term soil carbon store. Bacterial products also coat mineral soil particles with an organic film, on which such particles can be accumulated. Source: Fertile soil doesn't fall from the sky. The contribution of bacterial remnants to soil fertility has been underestimated until now (December 2012)
Tree-soil-microbe interaction creates limestone
Scientists have discovered a bacterium that can incorporate carbon dioxide into limestone, with the the help of a tropical tree and a fungus. Under certain conditions, the tree combines soil calcium with atmospheric CO2 and the bacterium creates the conditions under which it can be converted into calcium carbonate, depositing limestone around the tree's roots. This is a way of both improving the soil for agriculture or reforestation as well as locking away carbon in the soil and is already being trialled in several tropical countries. Source: Bugs in key role of CO2 storage method (June 2012)
Soil microbe erosion
The damage caused by wind erosion extends beyond the loss of soil particles, but the microorganisms that play such an important part in soil building and nutrient recycling. DNA sequencing employed in a recent American study (Agricultural bacteria: Blowing in the wind) shows that different groups responsible for various soil processes tends to be associated with different fractions (e.g. course particles versus fine dust).. these may be lost or retained depending on the nature of the erosion. The DNA technique, besides helping identify what may be lost during a particular erosion event, could also provide early confirmation of soil improvement from better management. (May 2012)
Poorly made biochar not beneficial
Biochar is becoming so popular worldwide that many people are now trying to make their own at home. A study at Rice University, USA, has found that the expected beneficial effects depends on how the charcoal is produced. The study found that unless heated to at least 450°C it could repel water and be less stable as a long-term carbon store, whether made from tree leaves, corn stalks or wood chips. Source: Cooking better biochar: Study improves recipe for soil additive
Biochar and earthworms get along
Reseachers have found that lack of moisture when dry biochar was incorporated into soil caused unwanted effects on earthworms. This suggests that when biochar is used in the field, pre-wetting or immediate irrigation after incorporation may be may be necessary. Fortunately, biochar was found to have no effect on the reproduction or immune systems of earthworms studied. Source: Study Finds Greenhouse Gas Reduction Strategy May Be Safe for Soil Animals (June 2011).
Biochar could help conserve water
Research at Tamworth Agricultural Institute is investigating the use of biochar on pastures. Results so far indicate potential for improving water use efficiency. Source (NSW Department of Primary Industries): Australian-first research looks at impact of biochar on water efficiency (April 2011)