Wheat Systems Trials Highlight Variety Variations
31/08/06

Some feed wheats are markedly more tolerant of variations in drilling date and nitrogen application than others, according to the first winter wheat systems trials conducted by Cambridge Arable Technologies at its Great Wilbraham site near Cambridge this season.

Averaged across the three popular varieties examined – Alchemy, Gladiator and Robigus - the trials showed a yield benefit of just over 1.5 t/ha and margin advantage of nearly £100/ha from mid-September drilling with 240 kg N/ha as against mid-October drilling with 200 kg N/ha.

While a three-spray programme using the newest fungicide chemistry and most robust PGRs maximised yields on both regimes, the highest margins in each case were achieved with a similar but lower cost programme involving more established chemistry.

“With wheat at £75/t, we generated an average margin over seed, fertiliser, fungicides and PGRs of £630/ha from our best value combination of earlier drilling with higher N and a more moderate fungicide input,” explains Richard Fenwick of CAT. “This contrasted with just £518 from our least profitable later drilling, lower N, higher fungicide input regime – an overall margin benefit of £112/ha.”

All three varieties consistently produced higher margins on the best value regime, with Gladiator delivering £662/ha from 11.13t/ha, Alchemy £644 from 10.91 t/ha and Robigus £584 from
10.06 t/ha.
Interestingly, though, clear differences were apparent in the extent to which the varieties tolerated later drilling accompanied by lower levels of nitrogen. On the most profitable fungicide regime, for instance, delaying drilling for a month and reducing N levels led Alchemy at the one extreme to lose over 2.1 t/ha and nearly £150/ha compared with 1.25 t/ha and just over £80/ha for Gladiator at the other (Table).

Table: Variety Performance with Moderate Fungicide Programme (CAT 2006)

* Margin over seed, fertiliser, fungicide and PGR

“As well as out-performing the other two varieties regardless of agronomic regime, Gladiator showed itself to be noticeably less affected by delayed drilling and lower N levels than Alchemy in particular,” Richard Fenwick points out.

“Despite Alchemy’s known preference for earlier drilling, the scale of this performance difference is surprising,” he remarks. “It suggests some varieties are best grown under more specific regimes than have traditionally been assumed while others are better suited to a wider range of drilling dates and fertiliser regimes.

“These differences are likely to be especially significant for growers wishing to maintain the greatest agronomic flexibility. They may also be of increasing significance in a future in which nitrogen efficiency is certain to become more important both economically and environmentally.”

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