7 June 1996

DEVON MAN SWEARS BY LUCERNE SILAGE

Lucerne guards against summer drought and boosts forage intakes on one Devon unit. Jessica Buss reports

LUCERNE silage is a valuable addition to cow diets in both summer and winter.

So claims Devon milk producer Jerry Alford, Silverton Park Farm, Exeter.

His 100 cows benefit from 1kg dry matter a cow of lucerne fed in the mixed ration in winter and are buffer fed lucerne bales in summer.

Mr Alford says the crop helps improve the ration balance. It provides a high protein forage that is particularly high in the amino acids methionine and lysine which are expensive to add as concentrates.

Growing lucerne suits his key aim of producing as much from home-grown forage as possible.

His sees forage intakes of 16kg DM a cow in winter and says offering lucerne as the fourth forage in the total mixed ration must help increase intakes. The winter ration also includes maize silage, grass silage and whole-crop wheat.

"If American cows give milk on feeds like lucerne why cant ours?" he asks.

Soils at Silverton Park Farm are not ideal for lucerne and it grew only 5.4t DM/ha (2.2t DM/acre) last year compared with typical yields of 10-13t DM/ha (see table). But it replaces 20t of 16% dairy cake which makes it worthwhile, reasons Mr Alford.

In ideal areas that have deep alkaline soils he recognises that yields would be much higher for the tap root could go down further. And although regular liming ensures the top soil on the farm is alkali, further down the pH is lower.

"Lucerne was grown for many years and was clamped in a tower silo but the loss of leaf at harvest also lost much of the goodness," he says.

However, Mr Alford finds that round baling allows more of the leaf to be preserved. This is the second year of growing the crop for baling with a chopper baler.

Lucerne can be sown in autumn or spring. Mr Alfords crop was drilled in the autumn of 1995 after set-aside.

To prepare the soil it was Paraplowed in case there was any compaction which lucerne is sensitive to. It was then ploughed and cultivated before drilling with a pneumatic drill.

Inoculant packs of rhizobium bacteria were mixed with the seed before drilling to aid its nitrogen fixing properties, he claims. After drilling the field was Cambridge rolled.

"Effective weed control is essential as the crop is not very competitive," he says. "But only one suitable spray was found for use on broad-leaved weeds for any spray that will damage clovers also harms lucerne."

"Now the stubble is sprayed with a normal rate of Gramoxone after a cut is taken. This keeps down weeds but does not damage the lucerne for it is cut down to 3-4in and has no leaf."

Lucerne is drought tolerant, but still needs moisture to yield well, says Mr Alford. The area has low rainfall at 711mm (28in) a year and in summer the crop can grow better than grass.

"The lucerne field received slurry and muck when it was in maize and this seems to help the crop that needs adequate phosphate and potash levels," he says. "But 100 units of phosphate and potash are applied each year after the first cut."

First-cut is normally taken in May after the crop flowers when it has been sown in the autumn. A spring sown crop cannot be cut in its first year.

Mr Alford aims for four cuts a year. But other areas may cut every four to six weeks, he claims. Cuts should be taken just before flowering.

The crop is cut with a normal mower without a conditioner. And swaths are left to wilt for up to 36 hours before baling but without moving them for this destroys the leaves. Bales made last year varied from 28 to 52% dry matter.

"Care must be taken when wrapping bales for stems are woody and, although expensive, a double layer of wrap may be needed," he says.

He advises avoiding cutting later in the season when there is a risk of frost. Enough plant is needed for the crop to build up its reserves for the winter. For best results leave 10-15cm (4-6in) of stubble so that leaf can grow again.

"The latest cut should be September 1," he says. "Last year we cut in October but we risked losing the crop.

"This crop is in its second year and may be taken up for maize next spring after a first cut. Another 10 acres will be drilled after a crop of whole-crop wheat is taken this autumn." &#42


&#8226 Maintain potash levels and pH.

&#8226 Delay very first cut until after full flowering.

&#8226 Allow root reserves to accumulate in late Sept and Oct.

&#8226 Wilt silage crops to at least 30% dry matter.

&#8226 Take care to avoid leaf loss when harvesting.

&#8226 Control weed grasses to maintain plant vigour.


Lucerne: Typical production and analysis

Annual yield (t/ha)

Fresh55 to 65

DM10 to 13

Quality

DM (%)15 to 19

D value55 to 60

Crude protein (%) 18 to 23

ME (MJ/kg DM)9.5 to 10


MANAGEMENT


FARM DETAILS


&#8226 Farm size: 130ha (320 acres) including cereals grown for cows.

&#8226 Stocking: 100 cows, 150 followers.

&#8226 Cow performance: 7800l a cow, 4500l from forage, 4.2% fat, 3.3% protein, 1.38t concentrate, margin over purchased feed 22.09p/litre, £1688/cow.

Autumn-sown lucerne at Silverton Park. Jerry Alford uses the crop

to maximise forage intakes.