2 November 2001

Sulphur shows promise as a sugar booster

A NOVEL hand-held device for measuring the sugar content of sugar beet crops in the field and clamp has helped to show that the use of elemental sulphur can boost beet sugar contents by up to 1.5%.

The device is not intended to compete with official sampling methods, but provides an idea of which fields to lift first and which stored beet needs delivery priority.

It has helped Lincolnshire company Boothmans Agriculture highlight the value of using elemental sulphur in beet.

"The last four years has seen a meteoric rise in the amount of sulphur applied to a range of crops," says Robert Boothman. "Last year we applied Brimstone 80 elemental sulphur to nearly 3% of the national potato crop to combat common scab and improve yield. It has also been used on rape, vegetable brassicas, onions, cereals and sugar beet. Many beet growers have claimed it improves both root yields and sugars so we set up a trial to back these claims."

Brimstone 80 contains sulphur in two forms, a small amount as sulphate to provide a quick fix with the bulk as elemental sulphur that has to be degraded by microbial activity before sulphates are released. That helps ensure leaching is avoided and provides a slow release for the crop.

It has been trialed on Henry Hirst Farms at Uffington near Stamford where 30ha (75 acres) of beet are grown on medium loam. It was broadcast as prills at 25kg/ha just after drilling at a cost of £14.40/ha (£5.82/acre). Beet was lifted on Sept 21 and roots weighed and sugar contents checked independently by Anglian Soil Analysis.

Establishment problems in one of the three plots resulted in variable root size, so further evidence for any effect on root weights is needed. However, it was clear that roots were bigger and heavier in the other treated plots than the untreated.

But most significant was the boost to sugar contents. Beet in the untreated plots averaged 18.64% compared with 20.26% in the treated plots.

Grower Philip Hirst admits being interested by the results. "They have whetted my appetite to know more about the potential value of elemental sulphur.

"When I looked at the five-acre treated block in mid-season there were no obvious benefits compared with the untreated 35 acres. But it seems there was a useful increase in sugars, so I want to repeat the trial next season."

No real benefits

British Sugar is also interested. According to Simon Fisher, trials over several years in sulphur-deficient areas have shown no real benefits from adding nutrient sulphur. "There have not been the sort of advantages seen in more sulphur-sensitive crops, but we are interested in any results that suggest a yield increase is possible. They need to be repeated in other seasons to provide the confidence for us to recommend the treatment."

He adds the Sugar Meter might prove a useful management tool, but because of the variability between individual roots it needs to be used on a representative sample.

Independent consultant Angus Kennedy of Beet Check agrees it could provide a useful indication of likely sugars, but wonders how this could be exploited in practice. "In a year of marginal sugars it may help a grower to pick the field with the highest sugar contents before lifting starts," he says. "But overall yield is more important and normally the worst field with the least potential should be harvested first." &#42

SULPHUR BOOSTS SUGARS?

* Elemental sulphur already used on a wide range of crops.

* Slow release of sulphates.

* Sugars up 1.62% in trial.

* Root weight rises also claimed.

A significant boost to sugar content of trial beets has whetted Philip Hirsts interest in the value of elemental sulphur treatment.

METER CANREADBEETCONTENT

The Sugar Meter, which is distributed by Lincolnshire-based Boothmans Agriculture of Bourne, comprises a tube with a lens at one end and window at the other. A slice of beet about 1sq cm and 1mm thick is placed in the window and sugar content can be read against a scale through the lens.

Unlike the polar meter used by British Sugar, which is highly accurate and can determine the level of sucrose separately from other inert sugars, the Sugar Meter reads total sugar content only.

Sugars peak as crops ripen in the autumn, so if roots are lifted too soon sugar yield is compromised. Using the held-held device early in the campaign could help growers plan lifting strategies.

In the clamp sugars decline as roots respire so later in the campaign beet with sugars nearing the 16% adjusted tonnage cut-off need carting to the factory before those with a higher buffer reserve.

The Sugar Meter costs £182 plus VAT and is available by mail order from 01778 394040.

SULPHURBOOSTSSUGAR?

&#8226 Elemental sulphur already used on a wide range of crops.

&#8226 Slow release of sulphates.

&#8226 Sugars up 1.62% in trial.

&#8226 Root weight rises also claimed.