23 August 1996

Matching hybrid to soil realises rapes potential

A Lincs grower with two years experience of hybrid rapes is discovering how to tap their full potential.

Robert Harris reports

HYBRID rape is now a familiar site on Martin Robinsons Priory Farm, Goxhill, in north Lincs. In autumn 1994, he was one of 14 growers across the UK to plant Synergy on a commercial scale.

The 9ha (22-acre) crop produced last years best oilseed rape yield in the country at 5.1t/ha (41.2cwt/acre). On the back of that, Mr Robinson doubled his area of Synergy last autumn and planted a further 1.46ha (3.63 acres) of a new fully-restored hybrid, codenamed NPZ 44 (probable name Artus), on UK agent CPB Twyfords request.

Despite what is generally regarded as an excellent season for rape yields, Synergy output slipped back at Priory Farm to 4.42t/ha (35.8cwt/acre). Artus matched it almost exactly.

Lower yields were the direct result of growing the hybrids on poorer land, says Mr Robinson. "Last year I grew Synergy on heavy clay. This year both crops were on lighter limestone soils."

Conventional variety Apex was grown on 3ha (7.4 acres) of even lighter land. Like last year, it yielded less than the hybrids. But the difference was less marked. Output was 3.58t/ha (28.8cwt) this year compared with 3.78t/ha (30.6cwt) last year.

"That was better than I anticipated, whereas the hybrid yields were a little lower than I thought. But, given the soils they were on, I didnt expect the hybrids to repeat last years performance. The heavier parts of the field did 40 cwt/acre again, but the lighter part of the field definitely showed a deficit."

Hybrid gross margins still hit an impressive £1062/ha (£430/acre). But that was about 10% less than last years figure, and just £50/ha (£20/acre) above the lighter land Apex – the gap was four times bigger last year.

That shows how important it is to match hybrids to good soils, says Mr Robinson. "It goes with the advice I was given. If either hybrid had been on heavy land, they would have done much better. I shot myself in the foot really, although it was due to rotational requirements."

As a result, he will stick with conventional varieties on his poorer land, and target hybrids to more profitable heavier soils. "20% better yield on a 1.25t/acre crop wouldnt cover the extra cost. But 20% of a 1.75t/acre one will."

&#8226 Mr Robinsons crop of Artus was one of three field-size crops grown in the UK. A further three fields of Pronto, also from German breeder NPZ Lembke, were planted.

Yields for both are running 1-2% behind Synergy, ranging from 4.45-5.4t/ha, says CPB Twyfords breakcrops manager Nigel Padbury.

Both are up for national list consideration this autumn. One or both will be taken on for further commercial assessment, and Mr Padbury expects them to be more widely available in autumn 1997.

&#8226 Plant on good soils.

&#8226 Drill at recommended rates.

&#8226 Top dress (add sulphur) early.

&#8226 Full fungicide programme.

&#8226 Control pollen beetle.

&#8226 Thick swaths slower to ripen.

These Artus swaths were so thick they took two or three days longer than Apex to dry out, says grower Martin Robinson. Keep combine choppers in tip-top condition to help dispose of the bulk, he adds.