As featured in Arable Farming Magazine
Building biomass for yield success
by Arable Farming Magazine March issue
Taking part in the Yield Enhancement Network (YEN) has provoked a radical rethink on his approach to growing crops for Aberdeenshire agronomist and farmer Iain Learmonth. Emma Penny reports.
For most farmers and their agronomists, being part of the Yield Enhancement Network (YEN) has driven them to think far more deeply about how they achieve maximum yields.
But for Iain Learmonth, the process has turned his thinking about farming and agronomy on its head.
Mr Learmonth has now won a YEN Gold award for wheat twice – achieving 102% of a 13.9 tonne per hectare potential wheat yield in 2020, and a whopping 107% of the 12.1t/ha predicted last year.
But it is the testing and learning process he has undertaken as part of his approach to YEN which has yielded some surprising results.
Farming with his brother Eric at Greens of Savoch, Ellon, Aberdeenshire, Mr Learmonth carries out most of the spraying, fertiliser application and combining on the 480 hectares they farm.
He combines this with his role as agronomist and director of Gardiner ICM, walking about 10,000ha in north east Scotland, so he is able to put what he learns from YEN into practice on a large scale.
He says: “The biggest thing I have learned as a result of this is it is surprising how critical wheat biomass is.
There are some things we didn’t know beforehand which have really turned our approach to it on its head.
Biomass “High yields and high crop biomass go hand in hand, so I now really focus on targeting plant population, early nutrition and plant health to make sure we get the biomass in spring.
If we don’t have it then, we will never get it back.
Early nutrition is critical.”
For Mr Learmonth, growing a high-yielding crop starts at drilling in late September; with no black-grass issues in Aberdeenshire, there is no need for a delayed start.
Variable rate drilling is used across the farm’s very variable soils, averaging 350-375 seeds/sq.m, but this could be as low as 300 or as high as 450 seeds/sq.m, depending on the soil.
As soon as the crop starts to grow in spring, usually in late February or early March, Mr Learmonth applies nitrogen and sulphur.
Aiming for maximum crop biomass means he has stepped up nitrogen applications from 180kg N/ha to 220kg N/ha, usually applied in a four-way split with 75% of it on by T1.
“This gives us the best chance of retaining tillers,” he says The farm, which is in an NVZ, also carries cattle, though their numbers have declined to 120 cows and their offspring which are finished on-farm, so soils are fertile through historic use of FYM.
The final N application will be tailored using a Yara N-Tester at flag leaf to determine the optimum rate.
Trace elements However, making decisions proactively and early is key if there are issues you know are likely to appear.
Mr Learmonth applies trace elements he knows are deficient, such as copper and manganese, as a matter of course, with the crop receiving its first application in mid-October.
“Manganese deficiency often appears here early, but I never wait until it appears.
I apply a few doses and start as early as possible.
By the time the crop is showing symptoms and suffering, it is difficult to recover and you can’t get that yield potential back.”
As part of YEN, he does tissue testing throughout the season, but believes waiting for results can lead to lost yield.
“It is interesting to see the results, but there is a lag between taking the sample and getting them.
So, if you discover the crop is low in zinc, for instance, while the time between sampling and getting the result might be a week, the crop will have done a lot by then.
A week can be too long and can quite easily turn into 10 days if it rains.”
Biostimulants have also been part of the testing and learning process he has employed for his YEN crops and others on-farm.
“I’ve found the results to be quite variable.
They seem to come into their own in a season where the crop is under stress.
In 2018, when it was exceptionally dry in mid-May and the crops were beginning to suffer, the results with biostimulants were very good.
But in 2019, when conditions were fantastic and everything grew like mad, the trials showed no benefit.”
However, given no-one can predict what sort of season is ahead, Mr Learmonth again employs a proactive approach and will use biostimulants if he believes they will help.
Rectify “You have to apply them before you know if you’ll need them; by the time you think you might have a problem, it may be too late to rectify it.”
This also applies to his fungicide programme and with Skyscraper as his current variety of choice, a robust approach is required, particularly as it is prone to septoria.
“It will vary according to the weather, but all our crops receive a similar programme.
We don’t skimp on PGRs either – it’s no use having a high-yielding, flat crop.
But two years ago, we had a huge crop and a thunderstorm at the wrong time and it did go flat.”
YEN’s focus on achieving maximum yield and breaking every component of crop yield down into its constituent parts has allowed Mr Learmonth to have a very practical on-farm look at what works, he says.
All members receive a comprehensive and detailed benchmarking report for their crop.
“I will look at the report quite a few times as there is a lot in there.
I look at what we could do better next year, and if yield has been limited, was it because of something I could do differently? “It has made me try a lot of things and as we are doing the trials on-farm, it gives me a good indication of how things perform in the north east of Scotland.
The knowledge helps other farmers grow the best possible crops too.
“Because of the nature of growing conditions here, there isn’t the same option to cut costs as there is in the south.
Fungicide and PGR programmes have to be much more robust, but on the other hand we don’t have to spend so much on herbicides.
Database “We’ve been able to show we can get very good yields in this area and as there are a few growers now doing it, we have a huge database of different farm practices and what makes a difference.
“For me, the impact of crop biomass has been the biggest thing I have learned as a result of this – I was surprised at just how critical it is.”
Greens of Savoch cropping
- 110 hectares spring barley
- 75ha winter barley
- 58ha oilseed rape
- 55ha wheat
- 16ha Ecological Focus Area/schemes
- Remaining 166ha is grass
Iain Learmonth’s 2021 YEN wheat spray programme
Autumn weed control:
Pre-emergence 0.6 litres per hectare Lantern (picolinafen + flufenacet) + one litre/ha Stomp Aqua (pendimethalin)
Mid-October 2.5 litres/ha ManCop
Spring T0 (GS 30):
One litre/ha biostimulant (Scyon) + 0.25 litres/ha Amistar (azoxystrobin) + 0.15 litres/ha Tempo (trinexapac-ethyl) + one litre/ha Stabilan (chlormequat chloride) + 0.75 litres/ha Provalia (metsulfuron-methyl + thifensulfuron-methyl + fluroxypyr) + 0.6 litres/ha of the biostimulant Phorce + three litres/ha ManCop
Spring T1 (leaf 3 fully emerged):
One litre/ha Lentyma (mefentrifluconazole + fluxapyroxad ) + one litre/ ha Arizona (folpet) + 0.3kg/ha Medax Max (prohexadione + trinexapac ethyl) + one litre/ha CCC750 (chlormequat chloride) + two litres/ha ManCop + one itre/ha of the biostimulant Calibra Carbo
Spring T2 (flag leaf fully emerged):
One litre/ ha Lentyma + one litre/ha Arizona + 0.35 litres/ha Telsee (ethephon) + 1.5 litres/ha Mag Super 80 + two litres/ha of biostimulant YieldOn
Spring T3 (early flowering):
One litre/ha Firefly (prothioconazole + fluoxastrobin) + two litres/ha Mag Super 80