30 November 2001

Success for lupins as whole-crop silage

SPRING lupins did exceptionally well in a trial to assess the yield and nutritional quality of pulses harvested for whole-crop silage.

"There is no doubt that they were the star of the show, but we need much more work on ensiling them," said Francis Dunne of Oliver Seeds, which sponsored the trial at Harper Adams University College.

Six varieties of peas and three each of beans and lupins were sown at the Shropshire college in the last week of April. Three replicates were planted and standard agronomy protocols were followed.

The objective was to harvest at about 30% dry matter. Samples were taken at 15, 10 and five days before, then five and 10 days after, forecast harvest date for DM analysis.

Peas were harvested in the last week of July at 27.8% DM and lupins a month later at 39.6% DM. The beans moisture content stayed high until mid-August then fell rapidly, so the crop was 81% DM at harvest, he says.

Bean varieties yielded 4.4t DM/ha (1.8t DM/acre) higher than peas at 12.8t DM/ha (5.2t DM/acre), but lupins yielded 2.75t DM/ha (1.1t DM/acre) more (see table). Preliminary lab results also show lupins to have the highest crude protein content, at 19.1% compared with beans at 18.2%, and highest protein yield.

Whole-crop peas competed better than beans on D-value, but the beans higher yield gave them a higher digestible yield of 6.6t/ha (2.7t/acre). However, with a 64.9 D value and high DM yield, lupins performed better, with a digestible yield of 9.8t/ha (4t/acre).

Analysis also indicated that whole-crop lupins had the best energy density, but detailed starch content results are not yet available.

Despite poorer performance than the other crops, Mr Dunne feels that peas performed well considering the late planting, with some of the new varieties, including his companys Oliver, looking promising. But there was a 2t/ha (0.8t/acre) difference in yield between the best and worst.

"There is no doubt that peas have become an established forage crop, their agronomy is well known and they can make a contribution to reducing protein bills. They are harvested early enough to allow August establishment of following crops, or can be an excellent nurse crop for grass, which can use the nitrogen they fix."

He says the trial shows that the two other pulses have whole-crop potential. But more work must be done on managing harvesting of beans as silage and on fermenting both crops to produce high quality feeds.

"We did not actually ensile and feed the material and our results are from using wet chemistry techniques. When all lab results are in, we will know much more about the different varieties of all three crops." &#42

Robert Davies

Whole-crop peas do have potential to reduce protein feed bills, but lupins outperformed them in recent trials.

Pulse whole-crop trial


Yield Crude Protein D-value

(t/ha DM) protein yield

% (t/ha DM)

Peas 8.4 16.8 1.4 57.7

Beans 12.8 18.2 2.3 51.7

Lupins 15.6 19.1 2.9 64.9