Archive Article: 1997/10/18
Plant growth stimulants, root enhancers or whatever – David Millar sorts through the various yield promoters that find their way into the tank.
ITS easy to dismiss the plant growth stimulants on the grounds of their old muck and mystery tag. But too many growers and too many trials commissioned by the makers suggest there are benefits to grain or oilseed yield as well as quality improvements.
On the other hand the results are remarkable for their inconsistency from season to season, and for the inability of the major independent research organisations to show clear financial benefit in their limited examination of a few products.
Now, to cap it all, Dalgety Agriculture is staking its reputation – and money – on the firmest backing for its root growth stimulant, Axis, by offering a full money-back guarantee if growers dont cover their costs.
Over five years of trialling with Axis on milling winter wheat, Dalgety says the yield benefit is worth just over £40/ha (£16/acre). The benefit is slightly less on feed types and on barley but still well above the cost of the product.
The mode of action claimed for Axis is fairly typical of all the growth stimulants. Hormones in the products supplement those that occur naturally and often help promote production of natural ones. Although often tank-mixed, most growth stimulants dont contain specific nutrients or trace elements which are usually applied well into plant growth cycles to correct specific deficiencies.
Several products are derived from seaweed but their preparation and the concentration of the active ingredients will vary. Omex Agriculture says that Kelpak is manufactured without the use of heat or dehydration. Yeald from Newman Agrochemicals is chemically-based, and termed by the company as a crop nutrition catalyst. Its benefits have been seen particularly in oilseed rape trials where a 6% yield increase in Falcon was seen in trials with SAC Aberdeen.
Newmans say Yeald works by increasing the root mass of the rape plants and their area by up to 22% within 24 days of spraying in the autumn between the 2-6 leaf stage.
Up to 30% extra root mass in cereals and rape is claimed for treatment with Redicrop 2000 which has the added benefit of osmoprotectants. These, it seems, complement plants natural defence systems against climatic stress by improving the firmness of plant cells.
The common complaint of inconsistency from products is prompting a new approach from Corby-based Maxicrop International which has taken a low-key approach recently to marketing its Maxicrop Triple. SAC research showed there could be a benefit from the product provided it was readily available when required.
To achieve this, Maxicrop is trying a new low-rate system beginning with seed treatment. Trial results with cereal yield improvements of 0.86t/ha are worth £52/ha (£21/acre) extra on farm gross margins.
Distributor Profarma, which sells the Goemar range of growth stimulants, has had them in its trials series with mixed results. The greatest advantages from treatment have come with crops in certain situations, such as under stress on light land.
NOT YET PROVEN
SIDE-BY-SIDE comparisons of the various plant growth stimulants are rarely carried out by the leading independent research organisations. The Scottish Agricultural College has been an exception.
However, even it has only had a limited look in its public research programme. Aberdeen-based Lawrence Morrice looked last year at Chariot spring barley treated with a small range of products.
The results for the one site were inconclusive. Only one treatment – with an NPK foliar feed – gave a modest yield response. In fact, the remaining treated plots showed a modest yield decrease compared with the 6.5t/ha (2.6t/acre) obtained without treatment.
Seamac PCT, Seamac Gold, Axis, Bittersalz (magnesium sulphate) and Headland Vertex were applied, according to the manufacturers instructions. "The difficulty with the trial is that when you analyse it there was no significant difference between any of these treatments," says Mr Morrice.