MGA lupin trial to study crops ration potential

14 August 1998

MGA lupin trial to study crops ration potential

By Jessica Buss

FORAGE lupins may prove a cheap-to-grow, high-quality protein feed to complement maize rations for dairy cows and beef animals.

In what is believed to be a world first, the Maize Growers Association is growing two crops of lupins, one in Oxon and one in Hants, to assess the potential for harvesting as a whole-crop forage, and feeding with maize silage, says MGA project organiser, Colin Wright.

"Lupins harvested as grain contain good quality amino-acid protein. We are hoping to replicate that in forage."

Hants grower Norman Light is pleased with how the crop has grown at Lower Bisterne Farm, Ringwood. He drilled 4ha (10 acres) with 125kg/ha (50kg/acre) of Athos seed from France, in a conventionally prepared seed-bed, on Oct 6. At drilling, a soil inoculant of rhizobium bacteria was applied to encourage nitrogen fixation.

Lupins are legumes which fix nitrogen, so may leave a residue for the next crop. But unlike most crops, they like an acidic soil with a pH of less than seven, he adds.

"No fertiliser was needed, despite normal to low indexes for P and K. A single herbicide spray of Stomp was applied pre-emergence, keeping growing costs low," says Mr Light.

Crop dry matter before harvest was about 12.9t/ha (5.22t/acre), based on cutting a small area of the crop, weighing it and sending a sample for analysis. That showed the fresh crop was 15% DM and had a crude protein content of 12.6%.

Mr Wright says that different harvest strategies are planned for the two sites in Hants and Oxon.

The Oxon site on David Christensens farm, will be dessicated and direct cut, while Mr Light planned to mow the crop, wilt it and use a forage harvester to pick it up.

But when the farms mower conditioner was tried in the crop, lupin pods were removed from the stalks and the most valuable part of the crop would have been left on the ground. The high volume of the crop also made the mower clog.

A neighbours drum mower was also tested in the crop. While this left pods intact it could not cope with the volume. Mr Wright was also concerned that too little stubble was left, which would mean soil would be picked up by the forager, and contaminate the clamp.

Eventually, the crop was cut using a 3m Niemeyer mower without conditioner. According to Mr Light, this worked because the space between the top drive mechanism and the cutting drum was larger, allowing more crop through.

After cutting, the crop was wilted for three days, lifing DM from 16% to 30% to reduce risks from effluent and poor fermentation. A precision chop forage harvester was used to pick the crop up. An additive was used, again as part of the trial, with half the crop treated and the other half clamped without additive.

Once clamped, Mr Light will study the crops feed value for beef cattle. He has two groups of 48 Aberdeen-Angus and Continental-cross Holstein animals, and plans to feed one group the usual diet of maize silage, grass silage and soya, and the other maize silage and lupin whole-crop. After a month, both groups will be weighed to assess their liveweight gain on the different rations. &#42


&#8226 Low growing costs.

&#8226 Initial harvesting concerns.

&#8226 Complements maize silage.

&#8226 Beef finishing trial.

Norman Light (left) and Colin Wright have conquered harvesting difficulties and are to trial lupin silage on beef finishers this winter.

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