10 November 2001

Hassle-free drill

A novel design enables this direct drill to match any conventional drill on crop establishment and yield, claims the manufacturer. Peter Read reports

A DIRECT drill without the problems of crop establishment and difficult grass weed control created by trash is what a New Zealand import, the Cross Slot, claims to offer.

It has not been seen in the UK yet, but dominates direct drilling in New Zealand: 6% of its arable area is direct drilled – and 90% of that is with the Cross Slot. A few are making their way on to farms in Australia, USA, Africa and Asia.

The manufacturer, Baker No-Tillage, claims that its unique cross-coulter design, which places seed and fertiliser in horizontal bands and to the depth you want, overcomes many of the problems associated with direct drilling. Indeed Dr John Baker is keen to distance the drill from the term direct drilling, which has negative connotations, and prefers to use the description no-tillage.

"For no-tillage to succeed, it must be fail-safe and deliver as good crop establishment as any conventional drill – but at much less cost," he says.

Direct drills have not been able to achieve this. He blames imprecise seed and fertiliser placement and straw trash: "Residues are pushed down into the seed slot, and in wet weather the resulting acidic conditions can kill the seed."

But the Cross Slot drill design helps to overcome those problems, says Dr Baker. A central disc makes an initial vertical opening and presses the trash residues down. Meanwhile seed and fertiliser are funnelled down two split tines at either end of a unique horizontal drill slot – both avoid contact with trash residues.

The logic being that fertiliser is close enough to the seed to boost germination, but not touching it and therefore avoiding scorch risks. Putting fertiliser and seed in the same slot is an option for those who prefer it.

By creating horizontal slots, rather than vertical or slanted slots, Dr Baker claims better control over the seed micro-environment. "A humidity of 90 to100% effectively creates a cold steam trap which aids germination. Tilled and disc direct drilled seed micro-environments only have a 60% relative humidity and so rely on moisture alone for germination."

Consistent

Depth control is by hydraulic over-gas rams: one to each opener. Each openers press wheel has an electronic sensor that senses soil hardness, continually altering the rams oil pressure. "This means depth control is consistent – vital for achieving target populations. Each opener can rise and fall by 0.5m, so that the machine faithfully follows the ground surface but has a constant downward force." Other machines use springs on the openers. "But they elongate and constrict, changing the downward force so that the sowing depth becomes inconsistent."

Fertiliser placement is altered by fitting different tine lengths. Disc depth has three different levels. Necessary field adjustments to the drill are few. Just seed depth and down force, and adjustments can be done from the cab. Maximum forward speed is 10mph. "But 8 or 9mph is more comfortable."

The downsides? The drill itself is heavy, so a downward force of 100 to 150kg an opener is needed. Thats power of 8 to10hp an opener: 130hp tractor for a 13-row drill and 170hp for 17-row drill.

And its not cheap: a 3m wide, 17-row air drill with Accord separate seed and fertiliser boxes costs between £45,000 to £50,000. Hi-Ab crane and slug bait box are optional extras.

Obtaining spare parts are often a problem with imported machines? "The Accord parts are obviously widely available in the UK. With the other parts buy spare parts and a spare opener complete set with the drill in the first years," he suggests.

&#8226 One UK grower who is interested in getting together with other farmers and importing a cross slot drill is Cornishman John Moss. He already direct drills (600ha) 1,500 acres of turnips, rape and grass. "I saw it put through its paces in New Zealand and was very impressed. Its engineering is far superior to anything else on the market. And I think the unique Cross Slot design and hydraulic control are an improvement on anything else on the market. The drills heavy weight means you get excellent penetration."