Don't forget less carbon emissions, greater soil retention of C, greater soil accumulation of C. Which means greater soil buffering capacity, greater water holding capacity but if poisons are used extensively then I guess all those benefits are wiped out.

A couple of other ways of looking at this: In straight energy terms Glyphosate and many other herbicides have about 10 times as much embodied energy per kilo as diesel. Say you apply a total of 1 kilo of active ingredients (herbicides) per hectare using zero till OR you can prepare a 1ha seedbed with say 2 extra tillages using less than a total of about 11 litres of diesel (quite possible) and use no herbicides, then tillage wins in straight energy terms. (I reckon 3 extra tillages or the use of a herbicide in the tillage-based system would tip things the other way). However, each tillage causes some C to be released from the soil and damages soil structure to some extent.

So from a straight emissions perspective in a cropping operation zero till would seem slightly more advantageous. In terms of climate change it would make a big difference if the manufacture of herbicides was done using green energy. Chemical residues, disease incidence, economics, organic premiums, whole farm planning etc introduce more complexity that could easily tip the balance the other way.

There is little doubt that we need to evolve a farming practice that uses less fuel, less fertiliser and less herbicides. Perennialising production, moving back to ley farming, biodiesel, rotational grazing and regional value-adding will all have roles.

Re poisons quoted above. The absence of tillage, compaction and the responsible use of herbicides according to label is shown to increase soil biodiversity and reduce the number of nasty bugs in the soil. I think that is a big benefit.

We must remember what motivated zero till in the first place. Erosion control was were it began, but as the system developed it became evident there were far greater benefits.

Increased infiltration, less compaction, earthworms returning, higher yields etc.

When we first started in zero till, glyophosphate was nearly $ 20 per litre. Usage rates per hectare have risen since then, but there are reliable technologies that can reduce fallow costs by up to 80pc. Weedseeker units spray only green weeds in the fallow, so instead of spraying the whole paddock, you only spray the weeds. This has a direct reduction in costs.

Grain prices have also risen, and I would dispute the figures in the article - all the budgets I have done with higher glphosate price and fertiliser prices, and higher grain prices have better gross margins than before.

The biggest issue we face on our farm is soil moisture. Zero till gives us the best chance of producing a crop. Soil moisture, storing every drop that falls from the sky is the key to farming in Australia.

Recent results in Canada from 30 year No-Till farm show a decrease in fertiliser requirement due to increases in soil carbon and improved soil structure, soil animals etc.

They are also doing some interesting work with forage legumes. Apparently they can 'reach' nutrients unavailable to cereals and the N fixed is considered valuable particularly considering N price forecast for 2009 which has Canadian farmers worried.

In WA, 'recreational tillage' was considered long ago to be unsustainable, mainly because the top-soil was finishing up in the Indian Ocean.

The observable benefits now with improved soil structure, increase in large and small soil animals and the ability to rotate crops and eliminate stock from the rotation, not to mention the availability of labour and the improvement in time of planting would make going back to the old systems plain silly.

The cost of chemical is not, or certainly should not be, the sole determinant when making the decision of which crop establishment technique to use.