TAG documents contain ‘most cost-effective strategies’

'The most cost-effective advice for the coming season' is how The Arable Group describes its 2008 Spring Strategies document, arriving with members this week.

Based on the latest TAG trials results and the general trials database, TAG says the strategies have validated the advice given the previous season.

"The 2008 document fully supports the advice given to our members last year," says TAG's Richard Overthrow, who has overseen its production. "And that's in spite of the unusual weather patterns we experienced last year.

"The documents are well regarded," he continues, "because of the essential advice pertaining to use of spring inputs such as nitrogen and growth regulators. For example, it's well known that our fertiliser advice is an accepted substitute for RB209."

Indeed, nitrogen was the focus for several TAG trials in 2007, the results of which fully supported the advice given to members earlier in the season.

"One of the main worries about last year's dry spring was that it would impact heavily on N responses," he says, "but our trials showed that nitrogen response curves were in fact very similar to previous years.

"Another significant point was that unless soil nitrogen levels were particularly high, the presence of residual nitrogen did not influence the optimum nitrogen dose for winter wheat."

With regard to nitrogen usage in winter oilseed rape, Mr Overthrow says the trials revealed that neither the percentage split of N nor the application dates are critical.

"It is more important to ensure that nitrogen is applied in good soil conditions conducive to uptake, rather than being applied primarily by calendar date," he points out.

"Application as late as yellow bud can avoid any yield penalty, provided the crop is not backward and the nitrogen can be taken up promptly."

Growth regulators also come under the spotlight, with a reminder to assess all the risk factors before deciding on PGR use. Soil fertility, drilling date and plant population, the variety's standing power and the effects of earlier management decisions – early nitrogen, for example – are all cited.