Brendon Cant brendon at iinet.net.au
Thu Mar 2 14:52:56 EST 2006

Crop Doctor 




Graingrowers could enjoy gross margin benefits of $750 per hectare over
three years by deep ripping their soils.


While subsoil constraints such as acidity and compaction significantly
reduce yields, they can be managed using amelioration techniques. 


A Grains Research and Development Corporation (GRDC) supported project has
revealed that the financial benefits of subsoil amelioration depend on the
severity of subsoil constraints, season type and nutrient supply.


CSIRO researcher, Dr Mike Wong said that three years of deep ripping in dry
years, at trial sites at Mingenew and Buntine, at a cost of $150 per
hectare, had negative results. 


However, he added that at both locations these losses were recovered in
average and wet years, giving a total benefit in a three year period of $464
per hectare in Buntine and $752 per hectare in Mingenew.  


GRDC supported researcher, Dr Wong said subsoil constraints, like acidity
and compaction, decreased root depth down the soil profile and reduced


In dry years, when May to October rainfall is below 150 mm, there is limited
water for the roots to absorb from the subsoil and ameliorating the soil
profile doesn't increase yields. 


Dr Wong added that ameliorating compaction in these situations might
increase early growth and development of increased biomass, resulting in
increased demand for water not supplied due to low rainfall.  


He said that improving a mild to medium compaction did not help until
seasonal rainfall was above 225 mm in an initially dry soil profile.


Dr Wong concluded that although subsoil constraints negatively affected
yields seasonally, the financial benefits of soil amelioration were
attractive, especially in wetter regions and on sandier soils.




The Crop Doctor is GRDC Managing Director, Peter Reading, Tel 02 6272 5525

Further Information: Dr Mike Wong, Tel 08 9333 6299

GRDC REF:CDFeb061/CSO00031/Blumenthal

Brendon Cant & Associates
Public Relations & Marketing 
Suite 5
4 Gugeri St
Claremont WA 6010
Tel 08 9384 1122


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