13 November 1998

Sunflower/maize is an energy booster

BI-CROPPING sunflowers and maize has produced a high-energy silage at Rodbaston with quality crude protein of over 12%, but drilling it can be a headache.

Thats according to farm manager Ian Sanday who has grown a 1.5ha (3.7acre) field plot this year at Rodbaston College, Staffs, to provide valuable winter forage for the 80-cow dairy herd.

Encouraged by trials at Reading University, Mr Sanday decided to drill a 80% maize: 20% sunflower mix – a ratio selected because more sunflowers could lead to shading and water competition worries – but finding a contractor proved difficult: "Not many are willing to invest the £40/seeder box cost of belts and wheels for sunflowers which is still a novelty crop," explained Mr Sanday.

Instead, a tall single variety of sunflower was sown by hand in late April. Only 40% germinated due to birds and mice eating the seed and rabbits grazing the plants, said Mr Sanday. Sunflowers were resown in early June and emerged when maize was at the six leaf stage. The actual growing mix was nearer 85:15 maize to sunflower.

Herbicide use is restricted by bi-cropping, but weeds were outpaced by both crops with some sunflowers reaching 3.5m (12ft). "When harvesting, care has to be taken to avoid sunflowers falling over the back of the header," says Mr Sanday. A corn-cracker is beneficial to ensure all maize and sunflower seeds are broken to aid digestion.

Although analysis of the crop hasnt been completed, the experience from Reading University suggests a 75:25 maize sunflower mix should have a crude protein of over 12.5% – compared to 8% for maize silage – and benefit from natural oils found in sunflowers. However, digestibility is likely to be almost three points below maize silage due to the higher fibre content, he told producers.

"Its a crop Ill be looking to grow next year. Ideally it wants to be planted within the rows to ensure a thorough mix in the clamp and harvested at 90 degrees to tramlines. Itll be interesting to see how it feeds out," Mr Sanday told producers.