Throws Farm Trials Pose Severe Second Wheat Test

September 2003 - Second wheat management has really been put to the test in Dalgety trials at Throws Farm in Essex over the past year in one of the most challenging local seasons for the crop in recent years.

Reflecting the experience of many growers in the area, second wheat yields in the nine variety trials were particularly poor this harvest. Indeed, in the absence of take-all seed treatment the control plots averaged just 6.38 t/ha, against the 8.9 t/ha recorded in 2002 - a drop of nearly 30%.

Amongst the recommended varieties, RL yield leader, Robigus fared particularly badly without take-all protection, producing 1.35 t/ha less than preferred second wheat, Consort at just 5.75 t/ha.

The severity of the second wheat challenge was underlined by the fact that even Consort was nearly 2.5 t/ha down on the 9.55 t/ha it produced as a first wheat under similar conditions in a nearby field; the penalty for Claire being more than 4t/ha.

"Our second wheats were really up against it this year," confirmed Dalgety arable technical development manager, Mike Jeffes. "Although we weren't able to drill the trial until the third week in October, the seedbed was particularly lumpy and establishment conditions difficult. "GS31 and GS51 root analyses showed relatively high levels of take-all in the control plots.

"Just as we thought, it turned out to be a particularly tough take-all year on the site. Not least because the scorching July took no prisoners among any less well rooted crops. Some plots literally died on their feet, allowing fusarium infections to take an additional toll. Differences between varieties were very marked. As were differences between the control plots and those receiving a specialist take-all seed dressing.

"So we weren't surprised to see such a wide variation in yields at harvest, with a particularly impressive 11% average yield benefit from Latitude (silthiofam) treatment, as compared to the 5-6% recorded last year. While all varieties showed a positive response to the treatment, this varied from just 1% to 20%, underlining the extent of possible variety/treatment interactions. "

Despite the higher 200 kg/ha seed rates used in view of the harsh seedbed conditions, Dalgety costings with wheat at £77/tonne and Latitude at £150/t show the 0.67 t/ha average yield boost giving a very worthwhile net benefit of £22/ha after seed treatment costs.

This compares with a break-even situation under the relatively low take-all conditions of last year's trial and wheat at just £55/tonne.

"Under these circumstances, we are convinced that growers keen to reduce their second wheat risks wherever take-all pressure is likely to be high should be treating their seed with Latitude," concluded Mike Jeffes. "Where disease pressures are lower the case for using the specialist seed treatment is less clear-cut; especially with varieties showing lower responses, if these prove consistent over several seasons.

"The great difficulty, of course, is predicting how serious the take-all challenge will actually be ahead of drilling," he accepted. "Growers can take heart from the fact that in a mild take-all and low wheat price situation like we experienced at Throws last year, Latitude treatment broke-even economically. However, treatment planning on the basis of good take-all risk assessment is likely to pay dividends for those wishing to make the very most from their second wheat management each season."