National Wheat After Set Aside Study Highlights Need for Management Care

April 2004 - Warm, wet spring conditions appear to be encouraging the early build-up of take-all in wheat crops this season, according to initial assessments by NIAB at its Cambridge second wheat trials site. Indeed, a NIAB take-all index of 19 recorded in root samples taken at GS31 suggests untreated second wheat crops, in particular, may be facing the potential for fairly serious 2004 yield losses from the disease.

The majority of UK growers believe wheat after set aside needs to be treated more like a second than a first wheat and are selecting varieties with a track record of second wheat success for this rotational slot, as well as managing them carefully for take-all, in particular.

These are the main findings of a special study undertaken by ProCam Agronomy this season to help British growers improve the performance of wheat grown after set aside. Conducted with 225 growers across the UK, it showed a high level of awareness of the particular challenges posed by wheat after set aside and the need to manage these crops especially carefully.

More than half the growers involved in the study saw the carry-over of root and stem disease from set aside as a concern warranting special care in subsequent wheat growing.

Just under 60% assessed this disease carry-over combined with September drilling as posing a significant take-all risk for wheat crops in many cases. As a result, well over two-thirds were keen to sow only varieties with a proven second wheat track-record after set aside; and a similar proportion felt new varieties should only be grown after a true cereal break to minimise the risk of failure in this challenging slot.

"Growers are quite clearly appreciating the need to manage wheat after set aside differently from wheat after a true break," observed Procam technical director, Dr David Ellerton. "Which is just as well, since in our experience the high levels of over-wintered grass weeds and volunteers inevitable in set aside pose a considerable wheat entry challenge. All the more so with earlier drilling increasing the take-all risk and decreasing autumn weed control opportunities.

"In such situations, we have often seen disappointing results from varieties selected solely on their first wheat performance or sown without a specialist take-all seed treatment. Yield recoveries from take-all treatment may not be as great as with true second wheats, but they are consistent across varieties and have invariably proved good value for money with wheat at £70/t or more." It is also important to note that earlier drilled wheat tends to be sown at lower seeding rates making the treatment cost per unit area very attractive.

Equally important in ensuring reliable wheat after set aside performance in Dr Ellerton's opinion are varieties with good second wheat track records.

Amongst current Recommended List varieties, a massive 75% of the growers involved in the ProCam study considered Consort a particularly reliable second wheat performer, with Savannah being highly rated by 34%, Napier by 30% and Option by 20%.

"While most growers understand the need to manage their wheat after set aside differently from their true first wheat, we cannot be complacent though, " Dr Ellerton stressed.

"Our study also shows a sizeable minority of just under 40% unaware of its special needs, with 30% failing to appreciate the extent of the take-all risk and around 20% happy to take the risk of growing unproven second wheat varieties in this slot. We clearly have our work cut out if we are to help everyone make the very most of their wheat after set aside in the years ahead."