10 May 1996

Clouds keep sugar down

SUGAR levels in grass could be lower than normal after the cold, cloudy weather so far this spring. "This will reduce the efficacy of certain silage additives," warns Aberystwyth-based ADAS consultant Philip Haigh.

He says it is worth remembering that the proportion of sugar in the grass leaf varies according to the amount of sun and rain. Levels in fresh grass range from 3.5% in a high moisture crop to 5% in drier conditions.

"So sugar levels could get worse if there is a sudden wet period and grass grows rapidly.

"Even if there is a sunny spell before first cut, it is now likely that sugar levels in herbage will be lower than normal unless there is a drought or silage is wilted," says Mr Haigh.

"When sugars are low, inoculant-type additives, which introduce desirable lactic acid yielding bugs to reduce pH more quickly, use sugar as a substrate and will be less effective," he says.

"Under these conditions, acid-type additives which reduce pH directly or by suppressing clostri- dial bacteria which cause spoilage could be the ones to use."