With enough of the wheat harvest complete to get a good idea of national yields, there is growing evidence that the ‘yield plateau’ may have been breached.
UK national wheat yields seemed to stagnate after the mid-1990s, with the UK average yield hovering persistently just around or below 8t/ha. Increasing concern within the industry led AHDB to commission a review in 2011 to try to determine the cause. The review, undertaken by NIAB, examined a wide range of data, including agronomic, economic and environmental data, to try to get to the bottom of the problem, according to AHDB research manager Dr Paul Gosling.
“The yield plateau report suggested several factors might be holding back yields, including sub-optimal N and S fertiliser use, soil compaction and a failure to exploit the latest agronomic advances by some farm businesses,” says Dr Gosling.
“So far, this year’s average wheat yields, according to recent ADAS figures, are 8.1 to 8.2t/ha. These figures are above the five-year average and a clear upward trend is starting to reappear in wheat yields once again. In fact, the five-year rolling average will breach the 8t/ha barrier for the first time – even if this year’s average is just 8.1t/ha.”
Varieties with better disease resistance could be a key factor, says Dr Gosling. “Evidence from the latest Recommended Lists harvest results shows that varieties at the top of the yield tables are associated with good resistance to septoria tritici.”
Management as well as genetic factors may also be at play, he says. “An increasing number of growers have started to focus more on soil management – from clearing field drains, to incorporating cover crops in the rotation – while others are starting to get a grip on black-grass control. Improved wheat prices may also have given growers more confidence to invest a little more in the crop.”
Recent world-record breaking UK wheat yields show what can be achieved when the crop is really pushed and the weather is kind, he adds. “While 16t/ha may not be possible for all growers, the return of upward yield trends now seems a real possibility. We appear to be heading in the right direction.”