Sweet smelling stubble

23 Feb 2012

Travels across Australia - cont

Farming in South Australia

I visited a farm today near Clare in South Australia.  It’s in a relatively high yielding area; achieving over 6 tonnes/ha of wheat last year.  This year the soil is still dry throughout the profile, so yields are predicted to be lower for 2012, and the grain price has dropped due to the strength of the Australian dollar.  So the financial shutters are coming down and every growing cost is being reviewed.

In neighbouring Victoria grain farmers have seen a doubling of total costs over the past 15 years.  Profit levels have remained roughly the same, but with enormous variations between years linked to rainfall levels.  Overall, growers have made money in around half the years since the early 1990s, but this hasn’t prevented an increase in debt.  Some have suffered a 5-11-year drought that they thought would never end.

Back to this morning’s farm visit.  The farmer was using soil probes to monitor water availability in the soil rather than using computer models.  Neither method appeared to be perfect, but they have a role to play in arriving at a decision where the skill and the intuition of the farmer is paramount.  A researcher recently reviewed the crop models and found them all pretty inaccurate in predicting yield, although some were OK in estimating water use.

The farmer has used ‘controlled traffic’ of sorts for the past seven years.  I say ‘of sorts’ because his combine header isn’t fitted to the system and he makes hay from oats, and many of those operations don’t fit in with the concept.

Despite the ‘of sorts’, the farmer says that water infiltration has improved to such an extent that his dams, which are ponds constructed at the bottom of slopes to catch run-off,  are no longer filling with water.  Obviously, Australian grain growers prefer the rain to be in the soil rather than running off it.

Talking to his consultant, it seems that adopting direct drilling using the knife coulters in the mid-1990s increased water infiltration rates due to soil residues being left on the surface, which reduced run-off, and an improved soil structure.  Controlled traffic may have further increased infiltration rates.

The other advantage he claimed from controlled traffic is a reduction in power required to pull the 11-metre direct drill.  He suggests that there has been a reduction of around one-third since its initial adoption.

Despite these figures, many of his neighbours have not adopted any system of controlled traffic.  This prompted a discussion on soil care.  This farmer, and another one I met later in the day, re-iterated comments I often hear from UK growers; when they take over new land the horsepower needed to establish crops is high, but adoption of measures to improve soil health result in a gradual reduction in power requirement and an improvement in yield.  These measures include working the soil only at appropriate times and using as much organic manure or amendments as possible.

This led me to ask one final question as I got into the Ute: why did the stubble smell so great?  Apparently it had recently received a locally sourced organic amendment - 2 t/ha of grape waste.  We tasted the non-waste portion at lunchtime.