More than three quarters of long-term forage maize growers are now harvesting the crop greener than they used to. Yet a substantial number have not changed how they preserve their crops.
These were among the key findings of an Ecosyl survey of how producers approach forage maize harvest and how the crop is ensiled.
Greener and less brown
Involving more than 100 UK producers, the results revealed that, among longer-term maize growers, 77% said the crops that they now cut for silage are greener and less brown compared to crops harvested 10 and 20 years ago.
However, of these growers, more than a third (37%) had made no or little change to the way they preserved their crops. And of those who had made a change, most (49%) had put more emphasis on preventing aerobic spoilage or silage heating, with fewer than half (45%) putting more emphasis on achieving a good fermentation.
“With the rise in popularity of harvesting maize while it’s still green, there could be different requirements when it comes to silage preservation,” says Ecosyl’s Colin Callender.
“Maize crops that are harvested as they die back and become brown and drier are likely to contain higher populations of moulds. These are the microbes that cause problems of aerobic spoilage or silage heating.
“By comparison, crops harvested greener are likely to contain higher levels of moisture,” Mr Callender explains. “In these situations, achieving a good fermentation to preserve the silage against the growth of undesirable bacteria can become an additional challenge.
“This isn’t to say that greener crops won’t also be at risk from aerobic spoilage. As a high energy silage, maize can be prone to this. But with greener crops, it could be even more important to consider both problems – both of which can result in losses in silage feed quality and in tonnes of dry matter.”
Mr Callender adds that clamp practices, such as good consolidation and effective sealing against air, will help against both problems. “But also check whether the additive being applied covers both bases,” he stresses “This is particularly important because it isn’t always possible to predict how late maize crops will be harvested and, therefore, how green or dry they will be.”