Strip Tillage six years on

June 2006
An encounter when cultivating land that was once stump country led Hugh Ritchie to develop one of the most commonly used minimum tillage practices in the Hawkes Bay today.

Back in the 1990s when turning over the ground conventionally, on stumped country, Hugh grew tired of chasing exposed timber with a bike and decided there had to be a better way. He was not the only disillusioned conventional tillage farmer in Hawkes Bay. Other farmers on different soil types were struggling with wind erosion, and low water holding capacity.

Fortunately the Hawkes Bay Regional Council was equally concerned about the soil on its patch and set about with Hugh, and other crop farmers to do something about it.

The now widely recognised farm research and development group Landwise was formed by both sets of parties in 1999 and became the platform, following a Nuffield Scholarship trip to the States, for Hugh to develop the first strip tillage machine in New Zealand. His scholarship to study sustainable irrigation and tilling systems enabled him to see first hand strip tillage machines cultivating in bands with minimal disturbance.

However, no such machine was available in New Zealand, so Hugh took the plunge and built his own version for $70 000 with a contractor.

The risk was rewarded.

Hugh runs a 1700 hectare farm across five properties, of which 700 hectares is in crop. He currently runs 500 head of cattle, 7000 breeding ewes and finishes 30 000 lambs. Cropping makes up 50% of his income, followed by sheep at 40% with the remaining 10% in cattle. This seasons 70/ha of maize, 50/ha of sweetcorn and 50/ha of squash has all been strip tilled and then drilled. All other crops are direct drilled.

Hughs machine can strip till six rows at a time but only needs to cultivate a third of the paddock by concentrating on the bands that the seeds are sown in. Depending on the crop, bands may need to be strip tilled twice before they are drilled.

Since the inception of strip tillage Hugh has seen improved soil structure, better yields and input cost efficiencies. Currently the strip till system costs only $80/ha as opposed to over $200/ha for conventional tillage cultivation.

Savings vary from season to season (last year Hugh spent $2000/ha on hand weeding compared to $110/ha this year) but on average he believes strip tillage is saving them around $350/ha annually.

The savings on diesel at a time when fuel prices have skyrocketed has also been hugely beneficial and is a major factor in why many farmers have taken on the new technology. The savings mean that we have 2-3 tonnes up our sleeve on yields if the crop doesnt do as well, he says. However, that doesnt seem to have been a problem with maize yields at a respectable 12-15 tonne/hectare.

Originally direct drills could not offer the kind of precision planting needed in crops like squash and that became a big advantage in strip-tillage systems. However that has now been overcome but there still remains the problem of plants such as maize that are prone to soil temperature stunting.

A little bit of cultivation, such as what is offered in strip-tillage warms and loosens the soil. This in turn evens the establishment which can sometimes be a problem in other direct drilling methods. Hugh says although the research hasnt been done in New Zealand to prove that theory, it has been proven in the United States. In sweetcorn direct drills can make it hard for the root to penetrate downwards.

Like all systems there are still some problems to be overcome including weed control. Grass weeds are becoming more of an issue, he says, particularly as weed mats get established after a few years of strip-tillage.

The other question revolves around fertiliser use. Should fertiliser be broadcast as it is currently or should it be banded beside the seed bed? If it is banded do farmers need to shift rows each year to stop the build-up of fertiliser? However, if rows are shifted that can cause precision problems.

We are still learning.