Many growers will be planning to get their winter wheat drilled early after harvest following last year’s difficulties
Many growers will be planning to get their winter wheat drilled early after harvest following last year’s difficulties. Dominic Kilburn reports on trials work that is aiming to help growers overcome the wheat yield plateau especially when drilling early and on lighter land.Recent results confirm that early sown wheat on light soils has the potential to significantly improve yields compared with later sowing on the same land. In addition, while lower seed rates improve variety performance on light land, the practise does bring its own risks in terms of an increase in foliar and stem-based disease pressure.These are the conclusions after two years of results from Agrovista light land, large plot, wheat drilling trials supported by Sentry Farms and breeder KWS.The trials, now in their third year, have evaluated the performance of several different varieties sown at two different dates and rates – early September and early-mid October – over three very contrasting seasons in terms of weather.Agrovista technical manager, Mark Hemmant (left) with Sentry Farms manager Matt Bell (right).“True light land yields are not represented in RL trials, and Sentry challenged Agrovista to improve its light land wheat yields,” said Agrovista technical manager, Mark Hemmant, speaking on the Denham Estate, near Bury St Edmunds in Suffolk where some of the trials work is based this year.
“Earlier sowing of wheat is potentially a key measure to reduce the impact of weather-related yield limitations, notably to lessen the effects of spring or summer droughts that have occurred in several recent seasons,” he explained.The trials work has also coincided with an HGCA report that has highlighted slower increases in wheat yields in the drier, eastern regions of the country compared with wetter and cooler west and northern areas, he added.According to Mark, light land wheat trials in 2010/2011 on Sentry land in East Bergholt on the Suffolk/Essex border, showed an average yield difference of 0.52t/ha in early sown wheat plots compared with late sown. “We deliberately put in some varieties like Santiago, not normally associated with being early drillers, to see how they would cope in lighter land situations,” said Mark. “There was a very bad drought that spring and the results mirrored trials that Agrovista carried out 15 years ago.”As well as Santiago, other varieties in the trial included Cordiale, Target, Conqueror and Grafton with the early plots sown on 9th September and the later sown on the 12th October. Early sown plots were drilled at around 110 seeds/m2 and later sown at around 275/m2.”Rooting studies in March 2011 showed much improved rooting with earlier sown Santiago rather than later sown. In the dry spring it was able to maintain its tillers and, looking at ear populations across all the varieties in July that year, later sown varieties had lost more tillers than earlier sown.”Harvest results at an Askham Bryan, Yorkshire-based light land trial in 2012, which turned out to be a very wet year, produced an average yield benefit of 1t/ha from the earlier sown plots including JB Diego yielding 9.78t/ha and Santiago 10.09t/ha. Both were sown on 5th September and at rates of 134 seeds/m2.In contrast, in the later drilled plots (18th October), at a rate of 350 seeds/m2, JB Diego yielded 8.58t/ha and Santiago 8.85t/ha.However, light land trials at Langham, near Bury St Edmunds in Suffolk the same season confirmed that while there remained a benefit from using lower seed rates when varieties are sown early, there was no benefit in overall yield between early- and late-sown plots at harvest.”The big question was; why?” continued Mark. “We saw little foliar disease at Askham Bryan that season as they managed to get the fungicides on at the right times. In Suffolk the spray timings slipped due to the wet weather and, with more septoria pressure, early sown plots weren’t able to keep up with the disease.”Just before the flag leaf spray there was too much septoria for the fungicides to cope with in the early sown plots,” he added, “and it confirmed that early sowing brings its own risks in terms of increased foliar and stem-based disease and BYDV problems.”With light land trials continuing at Askham Bryan and in Suffolk up to harvest this season, variety performance comparing Horatio, Kielder Santiago, Conqueror, Solo and JB Diego will be reported on in Farmers Guide when made available.Sentry Farms manager at the Denham Estate, Matt Bell added that because the company managed a lot of light land in drought-prone East Anglia, there was a clear incentive to investigate early drilling to try and break the trend of static yields. “There’s no doubt that there are savings in seed costs by early drilling, but growers must be committed to the extra management involved with earlier drilled crops,” he pointed out.”The extra pressure from grass weeds and disease is significant, and anything less than a full herbicide, fungicide and PGR programme, won’t suffice. But with extra management we are hoping that these crops can continue to build yield when we experience dry springs,” he commented.Not just about the variety
KWS’ John Miles (left) said that there was no hard and fast rule for early drilling varieties and, generally speaking, drilling early on lighter land was a grey area. “Data for early drilling is now available on the RL and RL Interactive with variety comparisons subject to a latest drilling date of 14th September. However the dataset is very small and possibly taken from land that is not particularly light,” he suggested.Text book characteristics for early drilled varieties, he said, included slow developing in the autumn; good standing power; good eyespot resistance (a notable problem for early drilled wheat) and good (marketable) specific weights.John claimed that it was very difficult to select current varieties for ‘true’ light land performance, and that many suffered when switching from heavy to light land while others, including Leeds, were more consistent across different soil types when early sown according to RL Interactive.”Do we really know what works in this position?” he questioned. “Probably not, but regardless of variety it is about managing inputs to limit the impact of water shortage, seed rates and PGR use, as well as nitrogen dose and timings and careful consideration of pest and disease risks and fungicide use that will determine a crop’s potential.”A variety is a small part of this but something we can influence,” he added.