28 February 1997

FEN BLOW BLOCKED BY A CHEAP CHOP…

Blowing soils and young sugar beet plants do not make good partners. One Cambs farmer who has suffered crop damage has found a cheap and cheerful answer. Robert Harris reports

CHOPPED straw and stubble are proving more effective at preventing soil blow in newly planted sugar beet fields than traditional cover crops. The new approach is cheaper too.

Greg Bliss, who grows 50ha (125 acres) of sugar beet on a range of soils, including black peat fen, at Ermine Lodge and Engine Farm, near Stilton, Cambs, tried the technique for the first time last year.

"The fields are quite exposed. We suffer from a snowballing effect – soil starts to blow further out in the fen, and by the time it gets here it will sandblast anything thats growing," says Mr Bliss.

His own black soil also blows. "If we get a lot of wind it can fill the big dyke alongside in three or four hours. I dont like giving soil away."

Cover crops have long been used to try to control the problem. But they are costly to grow and meet with mixed success, says Mr Bliss.

"We used to plough and press, then power-harrow before drilling the cover crop. We then rolled it in. But it was pretty hit and miss – the worst parts of the field grew the worst cover, and were most prone to blow."

Drilling date was often compromised, he adds. "You had to wait until the cover crop was big enough before you drilled." Early chemical choice was also limited to avoid killing the cover.

Mr Bliss decided to see if work carried out by British Sugar on blowing sands would suit his ground. "They used a Shakeaerator at 45í to the direction of drilling, then direct-drilled into the stubble."

He adapted the technique to suit his lighter soils. Preparations started at combining. Plenty of growth regulator is used routinely on the fertile soils, ensuring a strong, standing crop – vital to provide manageable straw. About a foot of stubble was left, and straw chopped and spread.

Wheelings were pulled out with a two-leg subsoiler. The 10ha (25-acre) field was then power-harrowed 10-12.5cm (4-5in) deep on Apr 24 prior to drilling, producing a soil/straw mulch.

Mr Bliss used his conventional Stanhay Rallye 12-row drill. "On the whole, our drill worked very well, much better than expected."

Straw snagging on the clod deflectors was the main problem. "We are on 18in rows, so its quite tight. Straw tended to bunch a bit, which caused one or two blockages."

The open nature of the mulch, even after rolling, made drilling into moisture difficult. That, and the dry spring, persuaded Mr Bliss to irrigate with 25mm (1in) of water to promote germination. "It may have been superfluous. But the crop of Saxon germinated very well."

Howling gales

The straw/stubble cover soon proved its worth. "We had some howling gales after drilling," says Mr Bliss. "Half of the same field was planted with onions and a cover crop. It blew and caused some damage. But nothing moved in the beet field."

Weed control was easier, since Mr Bliss could adopt a stale seed-bed approach right up to drilling in the absence of a cover crop. Roundup (glyphosate) was used in the autumn, and Scythe (paraquat) was used before drilling. "Before that we had to spray Goltix twice before beet emerged."

With no cover crop to destroy, Mr Bliss saved more money by being able to omit his usual application of Citadel (fluazifop-P-butyl). "I cant directly compare herbicide costs because I direct-drilled all the black land beet. But when we established beet conventionally in 1994, we spent £160/ha; this year, we cut that to £105/ha where we used straw."

Machinery costs are also lower. "We shall save a pass with the plough and a press, two power harrowings, a roll and a drilling. That must be worth £35-40/ha."

The only drawback is that straw seems to harbour insect pests, notably flea beetle. "Even with Gaucho-treated seed, we had to spray cypermethrin in June. A lot of the beet had been knocked back to the growing point by the cold, so it was a precautionary measure."

Average root yield was 47t/ha (19t/acre) with an average sugar content of 17.8%. "I was thrilled to bits considering the drilling date."

This year Mr Bliss is using the technique on 16ha (40 acres), with a few changes. A firmer seed-bed is a must, to ease drilling and to promote better seed-to-soil contact.

Roundup was sprayed into the wheat crop pre-harvest to improve weed control. Cultivations were brought forward to the beginning of December after plenty of rain had firmed soils. Mr Bliss used a new Cousins V-form flat lift teamed with an MF 8140, fitted with a front press and dual wheels to further firm the land.

To help straw flow more freely through the drill, Mr Bliss is replacing the standard clod deflectors with duck-foot tines. These will push clods and trash aside, creating a small furrow to give press wheels better contact with firmer underlying soil.

High yields of beet were easier and cheaper to achieve using the new straw cover, says Greg Bliss. Some modifications this season should produce a firmer seed-bed to ease drilling and improve germination.

Mr Blisss new Cousins flatlift has firmed soils better, and has left plenty of straw on the surface to act as a windbreak after drilling.

Simon Fisher raises the point that early-sown cover crops may not be practical for some growers.


STRAW COVER


&#8226 Cheaper than cover crop – £100/ha cost saving.

&#8226 Provides better protection.

&#8226 Existing equipment OK; slight drill modification needed.

&#8226 Easier and cheaper weed control.

&#8226 Lower machinery costs.

&#8226 Straw may harbour insect pests.