Second wheat looks like remaining a firm fixture in most UK rotations despite the impending three crop rule, escalating grass weed problems and weaker crop markets, according to the latest in the regular series of National Second Wheat Management studies.
Involving telephone interviews with more than 130 farmers across the main cereal growing areas of the UK this spring, the 2014 study shows 85% are intending to plant second wheat this autumn. This is slightly down on the 87% with the crop currently in the ground but markedly up on the 80% growing it in the difficult 2012/13 season. What’s more, there appears to be no significant change in the area of the crop being planned.
Unsurprisingly perhaps given this position, the majority of growers see the three crop rule having very little impact on their cropping plans. Instead, they continue to focus on doing everything possible to maximise second wheat performance.
“The fact that 50% of growers now see a yield gap of less than 1t/ha between their first and second wheats – against less than 40% in 2009 – suggests management improvements have being paying dividends in recent years,” notes study co-ordinator, Susan Mintern of Monsanto Crop Protection.
“Indeed, more than a quarter record yield gaps of less than 0.5 t/ha these days compared to just 8% five years ago. And almost 10% find the performance of their second wheats is now on a par with their first wheats.”
Concerns over grass weed – especially black-grass – control have escalated in recent years so that it now ranks alongside take-all among the top three challenges facing second wheat growers, with foliar disease control remaining very much in third place.
Selecting good second wheat varieties, using a take-all seed treatment and preparing better seedbeds stand out as the key management techniques growers are using to address these challenges, with applying earlier spring nitrogen and delaying drilling also practised by 70% or more (Figure 1).
“The same five second wheat management priorities were identified by growers in our previous 2009 and 2011 studies,” Susan Mintern points out. “Interestingly, while good variety selection and take-all seed treatment have continued to be the most important practices, preparing better seedbeds has become very much more popular over the past three years, in particular.
“This almost certainly reflects the greater reliance being placed on both pre-planting Roundup and pre-emergence herbicides in tackling difficult black-grass infestations. In addition to this, of course, better control over both grass weeds and cereal volunteers has the valuable addition benefit of restricting the carryover of take-all inoculum from the previous cereal crop.
“Such extra emphasis is welcome evidence of the extent to which growers are prioritising as many elements of improved best wheat establishment practice as they can despite the growing time and workload pressures they’re under.”
As part of this approach, the 2014 study reveals take-all seed treatment has become standard for more than two thirds of second wheat growers, with the vast majority treating all their seed.
At the same time, it shows a clear trend towards the use of the specialist fungicide, silthiofam (Latitude) at the expense of more general fluquinconazole-based dressings (Jockey or Galmano).
Despite recognising clear differences between the performance of varieties as second wheats, where their seed treatment decision-making is concerned fully three quarters of growers consider all second wheats to be the same.
“This and the very much lower importance given to considerations of affordability against expected cereal prices and immediate cash flow in deciding whether or not to treat underlines the scale of the financial risk take-all represents,” reflects Susan Mintern.
“All too often we see little relationship between obvious symptoms like white heads and both take-all root infection levels and yield losses in the field. We also know that even relatively good second wheat varieties can suffer badly from take-all. So it’s entirely sensible for growers to insure themselves against damage as effectively as they can by the routine use of Latitude in particular.
“In the 10 years since we introduced silthiofam to the UK we’ve seen considerable progress in the management and performance of second wheats across the country. Our research highlights the seed treatment’s value in promoting root development and tillering as well as restricting early take-all development, suggesting an important extra role in improving the crop’s weed competiveness.
“We look forward to recording further progress in closing the second wheat yield gap over the years as more growers make the most of every opportunity at their disposal to deal with both take-all and grass weeds to ensure the most sustainable wheat-based rotations possible.”