27 September 1996

Late maize frost factor

MAIZE is three weeks later than last year with some crops looking at a mid-October harvest date.

"This means that in some areas maize will not reach the ideal 30% dry matter before the frosts hit," says Arnood Hammeleers, who is based at SACs Crichton Royal Farm.

To assess when frosts are damaging the plant, he suggests cutting a sample plant at 1.5m (5ft) height to see if it has been frozen.

Maize Growers Association agronomist Simon Draper says that in marginal maize growing areas – areas which average under 1200 maize heat units a year – there is little point in delaying harvest after the average temperature drops below 14C to 15C, for the feed value of the plant will not improve.

"A late harvest and harvesting due to frosts means lower dry matters, so crops will be ensiled wetter this year. Because of the cold snaps there is also a high incidence of tillering which increases the proportion of green in the crop and reduces dry matter.

"In the clamp there will be greater run off and this takes with it a high proportion of the crops sugar," he says.

To reduce run-off he advises putting a straw base of 2.5cm-5cm (1in-2in) depth into the clamp. As an alternative he suggests spreading sugar beet nuts on the clamp floor and then in two or three layers as the clamp is filled.