10 September 1999

Oven test required

STAY green maize varieties require an accurate whole plant oven test rather than a field cob test to assess the crops dry matter before harvest.

Maize Growers Association agro-nomist Simon Draper says it is even more important to get DM correct at harvest for these varieties because the whole plant, not just the cob, is important for good maize silage.

But assessing DM accurately means using an oven test rather than the in-field thumbnail test used for conventional varieties, he says. Take a sample of 10 plants and then select at random two or three plants that can then be weighed and roughly chopped.

Each plant should be weighed and placed in a separate tin and dried overnight in an oven at 80íC (176íF). Once the maize is dry, re-weigh it and divide this figure by the original weight. Then multiply the average of the three plants by 100 to give the DM%. &#42