The success of conservation tillage around the world


Epicentre of the direct-drilling movement, Argentina has a long history of no-till success. That success was further bolstered by the mid-1990s introduction of Roundup resistant GM maize and soya to the point where nearly 100% of the country’s arable area is now direct-drilled.

After a long period of stagnant production and productivity, starting in the early 1970s, a number of independent but interconnected events fostered a new technological cycle that encouraged rapid growth in cereal and oilseed production.

Zero tillage and the introduction of genetically modified soya varieties were key elements of this change, which has significantly increased global supplies of soya, an essential food and feed crop.

Between 1991 and 2008 the total arable area in Argentina rose from around 15m ha to 30m ha. At the same time, zero-tillage expanded from about 300,000ha to more than 22m ha (from 2% to 75% of the total arable area).

Coinciding with this, the use of GM soya varieties has risen from less than 1% of total planted area in 1996–97 to an estimated 99% today.

The adoption of zero tillage improved soil fertility by reversing decades of soil degradation and created an estimated 200,000 new farm jobs.

The total economic benefits of zero-tillage in Argentina are estimated to be some $34bn, in reduced production costs for farmers, increased revenue in the plant breeding/agrochemical sector and most predominantly in lower food costs to the consumer.

In addition, a larger area can be planted in a shorter time, with just one tractor, a direct-drill and a sprayer. However, across Argentina nearly all field operations are carried out by contractors, irrespective of farm size.

Studies from Argentina’s main government-run research organisation – INTA – show that direct drilling typically improves yields by 20% at the same time as slashing establishment costs by 60-70%. Much of this improvement is put down to reduced moisture loss – critical in the high temperatures of an Argentine summer.

In addition, without weed control issues straw and chaff can be left on the surface helping to limit moisture and organic matter loss as well as wind erosion. Soil structure is also retained avoiding the problems of root stunting, surface slumping, smearing and capping.

It is also estimated that under a no-till regime, soil organic matter rises from 2.5% to 3.5% in the first 10 years.

These benefits were recognised in the mid 1990s when the province of Santa Fe granted tax exemptions for farmers adopting zero-till practices.

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