5 September 1997

Oven dry best for maize DM

MAIZE growers are urged to oven dry crop samples rather than relying on the thumbnail test to assess dry matter content and harvest date.

So warns Maize Growers Association agronomist Simon Draper. "Dry matter is proving tricky to assess this season. The normal fingernail test is giving misleading results."

In most cases, where grains on the cob are easy to pierce, the crop is not ready for harvest, while in a mature crop, piercing grains will be difficult.

This year grains may be difficult to pierce but are still wet inside, says Mr Draper. "We are not sure why this is occurring. The cob seems to be drying out more quickly than the plant, leaving a tough grain but a crop which is not at an appropriate DM for harvest."

He urges producers to oven test samples to ensure accurate results.

"Use the lowest oven setting so you dry rather than cook the maize. Chop the plant into inch squares to speed up drying, and weigh it before putting it into the oven. Leave it in the oven for three to five hours – or until there is no further weight loss – and weigh the plant again to obtain an accurate dry matter."n