How a crop feeds the ear in those final weeks before harvest can be critical to how it yields. CPM visits a Shrops grower whose on-farm trials are building understanding of the process.
There’s a big difference between the end of green leaf area and the end of senescence.
By Tom Allen-Stevens
It’s the last week of June, and there’s little doubt that Andrew Williamson’s crop of KWS Siskin winter wheat is feeling the heat of the midday sun. The leaves are curling at the edges, limiting the surface area exposed to the generous amount of sunlight on offer for this Shrops farm that sits on high potential silty clay soil.
But the flag is very much green and clear of disease. What’s more, the N-Tester readings – the main purpose of the visit to the crop – are showing there’s still plenty of nitrogen in the leaf and chlorophyll to keep the crop photosynthesising.
Andrew Williamson has been using an N-Tester to gauge nitrogen and chlorophyll levels in the leaf.
It’s this stage of the season that Andrew feels is crucial to how a wheat crop delivers on its potential. “There’s a big difference between the end of green leaf area and the end of senescence,” he says. “If the leaf shuts down too early, the crop starts putting assimilate back into the straw to keep it alive, rather than into the ear, and that’s when bushel weight suffers.”
The business, Beddoes and Williamson, farms 320ha of arable land that undulates between 100-200m above sea level, based at Upper Overton Farm near Bridgnorth. A keen advocate of precision farming, Andrew’s explored the variability of the land he farms, and it’s his quest for answers that has led him to his own on-farm trials.
Helping him in this quest is Bayer’s Will Charlton, who’s joined him to inspect the crop. As a member of Bayer’s Xpro Farmers Club, Andrew’s doing some Judge for Yourself trials, that put the company’s SDHI chemistry through its paces.
For the past two years, as well as resourcing and helping to administer the trials, Bayer’s been monitoring the performance of the wheat trial. This has included using
a drone, as well as the N-Tester, while leaves have been sent for analysis to test for latent septoria levels. There’s also a similar trial underway in Andrew’s barley crop.
“The testing will tell us not only the green leaf area, but the photosynthetic capacity of the crop,” says Will. “This is the third year we’ve had Ascra in the Judge for Yourself trials, and it’s often difficult to see much in the way of a visual disease difference, but we do generally see a yield lift.
“We’re keen to attribute the causality of this yield improvement, and pinpoint how growers can make the most of it, which is why we’re working with farmers like Andrew to understand more about what exactly the crop’s doing at the end of the season.”
The wheat trial is also Andrew’s entry for the Yield Enhancement Network (YEN), that helps growers understand the yield potential of their crop and applies a scientific approach towards striving to achieve this. It’s Andrew’s third season in YEN. “I use it mainly as a benchmarking tool to compare my crop’s performance with others,” he says.
“The main aspect to aim for is to build biomass. But the biggest-looking crops don’t always give the best yield – you not only have to build the biomass, you have to sustain it too, and much of that comes down to the weather.”
Results have shown that some of the highest-yielding crops have ear counts of over 600 ears/m². Andrew’s crops have averaged around 350-450 ears/m², so he’s focused on trying to build that. “We don’t know how the weather will pan out, but if we at least set the crop up right and treat it right, then if we get the right conditions, it’ll yield.
“It’s a bit like the three little pigs building their houses – if there’s no wolf then all three houses are fine. But in farming, there’s always a wolf, so you need to start with the strongest foundation.”
Initial results suggest the crop could have built the potential he’s after. “Last year our ear count was 300 ears/m², but this year it’s up around 500 ears/m²,” reports Andrew. “Considering the conditions we had in early spring, the crop’s not done bad. I would have liked to have applied the first dose of fertiliser earlier. In parts of the field, where it’s very light or heavy, the crop’s suffering where it doesn’t have the roots. But for the most part, it’s bearing up well.”
It’s not just about building ears, though, it’s about sustaining them, which is where he’s hoping the Judge for Yourself trials and the close monitoring will provide some answers. “The aspect I like about these trials is they’re not only on your farm, but you do the work and interpret the results yourself – it gives you far more insight into what the crop’s doing.”
Last year, the Ascra plot yielded 0.79t/ha more than the comparison treatment, and an analysis across the YEN results is quite revealing about where this came from. “Although our ear count was in the lower quartile of results, our grains/ear, at 62, was in the upper quartile. So overall our grains/m² were a shade higher than average.”
This suggests the crop was relatively successful at hanging onto its green leaf area and feeding the grains. But will it do the same this year, with the higher ear population? “The two seasons are complete polar opposites,” notes Andrew.
“Last season was fairly dry all spring, and a low disease year until T2. Then we had fairly regular rainfall. This year it’s been fairly wet throughout March and April, but you can see to a line on leaf two where the weather dried up.”
The N-Tester results have shown the crop has maintained adequate chlorophyll in the leaf throughout the latter part of the spring. “We won’t know the results nor be able to draw too many conclusions until the combine goes through. The important aspect is that we’ve captured all the monitoring data during the grain-fill period, so we should be able to draw some reasonable conclusions,” Andrew points out.
He’s also considering what other Judge for Yourself trials he’ll do through the XFC group. “I like the interaction with other farmers in the group – it’s a good forum to share ideas, and you learn things you wouldn’t if you just stayed on your own farm.”
One plan within the group is to investigate the potential of shifting the SDHI timings from T1 and T2 to T2 and T3, specifically to aid green leaf area retention. “But I think that’s a risky strategy. Where we are, you always get septoria in the bottom of the crop and need to get on top of it early to keep the crop in a protectant state – you could easily lose the green leaf before having any chance to retain it.”
But he’s keen to explore the potential of biostimulants. “I’d see them as a support to what we do to keep a crop healthy, and a means to rely less on the chemistry to do all the work. Perhaps there’s a natural immunity a wheat crop has that we tend to throw away as soon as we add fungicides.
“Stimulating these natural defences early in the season may then mean you can focus the SDHI later in the year to retain the green leaf. You can bring in soil health as well – going forward I can see there’s a lot of potential in using fungicides as a strategic component of a plant health strategy, rather than just a defence against disease,” concludes Andrew.
Drone flights pick out the difference
What the eye can’t see, a flight over a crop with a drone generally can, especially if it has the right camera attached and is flown by a professional.
Russ Delaney of Agrivue previously flew Gazelle, Lynx and Apache helicopters in Bosnia and Iraq. The flights over Andrew’s cereal crops may not be quite as intrepid, but new technology is bringing some interesting results.
“The drone is fitted with a multi-spectral camera that enables us to pick out the Normalised Difference Red Edge Index (NDRE). This highlights the differences at the far-red end of the light spectrum much more clearly,” says Russ.
The images are being used by Bayer to provide more insight on what Ascra is doing for the crop, particularly towards the end of the season, reports Will. “Last year, where we flew the drone over the Judge for Yourself plots, the NDRE images picked out quite clearly some of the tramlines where Ascra had been applied, and these correlated with trials where it gave a yield advantage. We’re hoping to repeat that result this year to build a clearer picture on how the treatment is best used.”
New product under scrutiny in barley
There’s a new SDHI-based product being put through its paces in Andrew’s barley Judge for Yourself trial. “Our normal practice is to apply two applications of Siltra to the winter barley, but is this the right course of action?” he queries.
As a sink-limited crop, ear number and tiller number are critical for winter barley, he notes. “You have to build a good, thick crop early on, and you don’t want to let it go yellow coming out of the winter as that’s a sign the crop’s losing tillers. We didn’t get on with the nitrogen as early as we would have liked this year.”
The new fungicide was applied at the T2 timing against Adexar. Will reports that it’s also being trialled on other farms and in spring barley. “We’re trying to keep the way it’s used consistent across trials, placing it at only one timing so we can build a clear picture on how it performs. Ideally, that would be T1 in winter barley and T2 in spring barley, which is the timing that tends to bring most benefit from using an SDHI,” he says.
Going for green: the SDHI programmes on trial
Partners in Performance
Partners in Performance is the result of a long-standing collaboration between Bayer and a group of progressive growers.
It started in 2011with the launch of Aviator Xpro when growers were invited to trial Aviator on their farm. In these split-field trials Bayer took a back seat with the only demands being the field area for fungicide comparison and crop yield verified over a weighbridge or via combine yield monitor – everything else was down to the farmer.
Over time this developed into more of a club. Each year the farmers would meet to discuss results, listen to guest speakers and debate winter wheat management issues.
Farming has always been a challenging business, and with Brexit those challenges have intensified. The margin between profit and breaking even is likely to become even tighter and any incremental gain will be needed for sustainable combinable crop production.
To achieve that the industry needs to work together to share the latest research and thinking, exchange ideas and experiences.
Partners in Performance aims to bring farmers and specialists together to develop solutions to improve crop performance and investment return.
