Letter from Europe: Controlled traffic farming winning favour with European farmers

Saturday, May 10, 2008

Already in vogue in Australia, CTF offers better soil care with reduced inputs and higher yields - and with a carbon footprint that promises to be the lowest of all crop growing methods

by NORMAN DUNN

Back in the 1930s, when most plows were still pulled by horses, the estimated pressure applied by machinery 40 centimetres below field surface was around 0.1 bar or some 100 grams per square centimetre. Nowadays, on the average arable farm, it's nearer 2.5 kilograms the square centimetre, says engineer Tim Chamen, speaking at a workshop for controlled traffic farming (CTF) in the Netherlands.

CTF has a big role to play in reducing soil compaction by modern cultivation and harvesting heavyweights - and also in lessening farming's carbon footprint through cutting back on arable inputs and encouraging soil humus levels with associated reductions in CO2 and N2O emissions.

At the same time, it's a concept which substantially increases yield potential on almost all soils with fertilizer uptake improved by up to 15 per cent. Conventional minimum till in Europe can mean over 90 per cent of field surfaces driven on at some time during the season. CTF can reduce this to as little as 20 per cent through planning the minimum number of permanent tracks across the field to be driven on year after year.

Ideally, axles should be adjusted so that machinery shares the same track width. Implement working width has also to be planned so that the same tracks are used as often as possible, for example by teaming up three metre drilling with six metre cultivation and 12 metre combining widths.

Tim Chamen is one of the pioneers of the concept, having begun work on controlled field traffic in the early 1970s and now continuing the concept's development as chairman of the CTF group within the International Soil and Tillage Research Organization (ISTRO). He's in chargeof a 20-acre heavy clay soil site in England, where CTF has been undergoing trials for three years now, sponsored by a raft of international agri-businesses headed by Unilever.

Soil structure has visibly improved in the field with substantial savings in time and labour during cultivations. Results from other tests indicate that these savings could be much higher when highly accurate RTK-GPS satellite navigation is used. For instance, cultivator overlap could be reduced to three centimetres compared with 50 centimetres on land with no tracking guidance. Not surprisingly, the news this spring from Britain is that crop producers farming around 15,000 acres are now planning, or have already started, CTF operations.

In the Netherlands, a batch of mainly vegetable growers are also convinced that controlled traffic is the way ahead - aided by the country's Plant Research International institute, which is carrying on CTF work it started in the 1970s, initially with sugar beet, potatoes and onions. Dutch research includes a comparison between commercial farms over the last four years with results in CTF favour including a 15 per cent increase in spinach yields and 10 per cent more onions cropped. Additionally, nitrous oxide (N2O) emissions from the soil have been cut by 20 to 50 per cent and there's been a reduction in weed pressures.

Some Danish farmers have also started the system and among the results is a claimed average cereal yield increase of eight per cent by one farmer compared with non-CTF minimum till land and a whopping 25 per cent reduction in fuel costs through less cultivations and no overlapping.

An RTK-GPS system doesn't come cheap, involving a capital investment of around $55,000. But even spread over just 500 acres of winter wheat, spring barley and oats, Danish farmer Ole Green reckons that he would break even with fuel savings of 25 per cent and yield increases of eight per cent - and expects no trouble in achieving at least these targets.

In Denmark, according to Tim Chamen, 10 dairy farms are now operating the system on some 3,000 acres of grassland with another 20 farmers applying CTF for heavier operations only, such as liquid manure spreading. Overall, farmers in eight European countries have indicated interest in the system by joining CTF Europe Ltd., an international support group administered by Chamen.

But the European work seems very small beer indeed in comparison with the advances of CTF in Australia, which now has around 2.5 million acres growing crops under some form of permanent track system. In fact, one in five grain growers in the country were applying CTF principles in their cropping by the end of 2007.

Cutting costs is fine and, of course, more yield is always welcome. But perhaps the greatest gain offered by this system is the sparkling climate-saving image it can give to farming everywhere. With its reduction in fossil fuel requirements and related cutback in CO2 and N2O emissions, controlled traffic farming looks like playing a promising role in global warming reduction. BF

Norman Dunn writes about European agriculture from Germany.