Soya undergoes whole-crop trial
By Jessica Buss
PRODUCING a whole-crop soya bean forage for feeding milking cows could help overcome grain maturity concerns for this high protein crop.
Alfred Frampton, of Holly Farm, Owermoigne, Dorchester, Dorset, is one of 13 producers across the country growing a crop of soya beans for whole-crop. He believes that harvesting mature beans would pose too many difficulties.
"Soya beans would need heat treatment before feeding to remove tannins and we would need to be sure they would mature." Suitable storage that met his milk buyers requirements for concentrate feeds would also be costly.
But he is interested in soyas potential as a cheap source of forage protein for feeding his high-yielding 170-cow dairy herd which averages 8223 litres. Cutting soya at a less mature stage and clamping it in a silage pit as a whole-crop could overcome the difficulties of crop maturity, post-harvest treatment and storage, he believes.
Soya beans were not Mr Framptons first choice for a protein forage. He wanted to try lupins but no-one wanted to supply the seed. Then he was offered French soya bean seed from Grainseed. This was sown on 3.2ha (8 acres) of his 144ha (360 acre) farm. He is also growing 16ha (40 acres) of peas for crimping for the first time this year.
Soya was drilled into a seed-bed which received a generous application of slurry before ploughing to incorporate 370kg/ha (150kg/acre) of 20.10.10 fertiliser. Seed was drilled on May 13 using a corn drill with every other coulter blocked to give 17.5cm (7in) row spacings. The seed was treated with a rhizobium inoculant as it was loaded into the drill to encourage nitrogen fixing.
"Within 24 hours root shoots had developed on the seed, and the hot weather that followed saw seedlings come up in a few days. At that stage it looked promising," says Mr Frampton.
"Then fat hen seedlings came through, so on June 4, a herbicide – Flex – was sprayed. This burnt the weeds and scorched the soya. But when the sun came out, the soya recovered. However the soya didnt grow quickly enough to out-compete weeds and stop them germinating because we had so much rain."
But, he says, the field is a well known weed trouble-spot – even maize crops have suffered in previous years on the sandy soil. Seed supplier, Grainseed, adds that weeds and birds have also caused difficulties on other soya whole-crop sites.
The field was selected for soya because it can be irrigated, but high rainfall means that has not proved necessary. If the crop is successful he plans to grow future crops on another soil type on the farm to reduce weed concerns.
Mr Frampton decided not to apply another herbicide because he hopes more sun will help the soya overcome the fat hen. The crop should need no other inputs before harvesting, probably in September.
"We must harvest the crop once the green beans are formed but before the bean is dry. We hope that we can direct cut it using a Kemper header." The alternative is to cut the crop and let it wilt, but he is concerned that the lack of stubble to hold the crop off the ground would lead to soil contamination and poor fermentation. He has yet to decide if an additive will help with crop fermentation.
The crop will be clamped separately from other forage to avoid any cross-contamination and so allow a true assessment of its feed value, which should be about 20-22% crude protein. It will then be fed with grass and maize silage through a mixer wagon. *
• Low input crop.
• Cut before mature.
• Expected crude protein content 20-22%.