As one lifting season ends, another drilling campaign begins. With the help of Norfolk farm manager Mike Wilton, we take a look back at the challenges of 2020, and what the 2021 season holds for the forthcoming sugar beet crop.
Managing a total of 1,800 hectares of owned and contract-farmed land near Holt in north Norfolk, Mike Wilton is farm manager of Stody Estate Limited owned by the MacNicol Family. The business has a diverse and long rotation with root crops including, carrots, parsnips, potatoes and sugar beet, and a range of cereal crops and maize as break crops. A lot of investment has been made to irrigation provision, with any non-irrigated land mainly growing combine crops and energy crops to serve a local anaerobic digestion plant.
Around 200 hectares is down to sugar beet on a six-year rotation, and the farm usually supplies 13,500 tonnes of sugar beet to British Sugar, mainly via the Cantley factory. The business took a small tonnage holiday in 2020-21, delivering 11,000 tonnes on contract, but Mike expects to be back up to 13,5000 tonnes for this coming season.
The crop is established behind the plough on a ‘just-in-time’ basis, with ploughing, seedbed preparation and drilling all done in quick succession. Mike says it gives them the best establishment on their light sandy/loam soils, resulting in plant populations of around 95,000 to 105,000 plants per hectare.
“The crop got away quickly last year. We were helped by the good weather and that we’re on light land, but it did come under significant aphid pressure. We were watching the BBRO aphid survey forecasts and regularly inspecting crops. Every field was treated twice with an insecticide, with the worst-infected fields getting a third spray,” explains Mike.
Crop safety considerations, and the need to achieve maximum efficacy with the applied insecticides, meant herbicides were not tank mixed with any aphid sprays. This meant fitting herbicide applications in around other sprays.
“This effectively increased the workload for the sugar beet crop and invariably some things suffered, whether that was slightly poorly controlled weeds, or less-than-ideal timing of an insecticide for aphid control,” says Mike
“However, in this part of Norfolk we have been quite lucky, in that the aphid pressure was relatively low compared to other beet-growing areas, and we managed to satisfactorily manage the populations. So, although there was some impact from the challenging spray programme, overall it wasn’t too dramatic.”
Mike’s disease control programme is planned to fit expected lifting dates, with Escolta the mainstay of the programme in 2020 to target mildew, rust and Cercospora Leaf Spot. The crops planned for early lifting received one fungicide application, the mid-lifting had two applications, and the late lifting was scheduled to have three, but because of heavy rain towards the end of September it wasn’t possible to travel, so it also received two fungicide sprays in total.
“I don’t think missing the third spray was that detrimental in the end,” says Mike. “Although we did see a lot more Cercospora coming in late to the crop. It’s possible that it was a result of the missed final spray but I can’t be absolutely confident of that.”
Mike explains that he saw a big difference in incidence of Cercospora across the varieties he grew, and that next season he’s going to be monitoring the disease much more closely, to get a better view on what decisions have the most impact, from variety choice, to fungicide application.
With the loss of desmedipham, Mike admits that weed control was a little bit of a challenge last season. While he had some product on-farm to use within the use-up period, he struggled a bit once it was finished.
With potatoes in the rotation, controlling volunteer potatoes drives the chemistry choice, along with the need to control fat hen, polygonums, speedwell, poppy, cleavers, some brassica weeds and volunteer oilseed rape.
“We used Betanal Turbo early on as a safe, reliable herbicide for our first weed control spray, before moving into a more robust programme. Generally, we aim for three to four herbicide sprays, with a range of actives across the tank mixes, including clopyralid, ethofumesate, lenacil, metamitron, and phenmedipham.
As well as a robust insecticide, herbicide and fungicide programme, Mike is keen to promote good plant health through an integrated approach of appropriate nutrition, sufficient soil moisture, and biostimulants such as amino acids, Cytokinin, Phosphites etc. to promote rapid growth, and a darker green leaf area.
The farm has invested heavily in water, and Mike is now applying more water to the sugar beet crops with a view to growing a smaller area with higher yields per hectare. Irrigation is on a scheduled basis from as early in the season as the crop needs. The choice of which field to irrigate often comes down to which offers the best yield potential and has ease of access.
He applied two to three inches of water (50 -75 mm) to selected crops over the 2020-2021 season as a cost of around £100/ 25 mm per hectare.
The 2021-22 season presents Mike with opportunities to make some changes to his crop protection programme.
Depending on the aphid forecast in February, an emergency authorisation for the use of neonicotinoid seed treatment thiamethoxam may be granted. If this authorisation is given, Mike will have all of his seed treated.
He says, “My personal view is that over-spraying with broad-spectrum insecticides is more environmentally damaging than the use of a more selective neonicotinoid seed treatment. And, although it is slightly less costly using the seed treatment over two or three insecticide sprays, I’m far more interested in doing the most effective thing for the crop and the environment.
“My only concern now is the timing of any authorisation decision and the need to get seed onto farm. If the decision is delayed until close to March, we’ll likely have seed delivery pushed back. If that happens I still think the advantage of the seed treatment will outweigh drilling earlier, although there is a limit to how far I want to push my drilling back. I’m hoping to be done by Easter Sunday!”
Mike is also making changes to his weed control programme, with the loss of desmedipham. The most crucial thing for him in early herbicide applications is crop safety, so the first post-emergence application will be Betanal Tandem. Once the crop is more robust, the programme will be much like it was in 2020 with tank mixes containing different chemistry and modes of action.
Because weed beet is a problem in some fields, Mike has been trialling the Conviso Smart system for sugar beet. This involves using hybrid sugar beet seed developed by KWS which carries specific tolerance to the ALS-inhibitor based herbicide Conviso One, developed by Bayer. This offers robust control of broad-leaved weeds, including weed beet, and some sensitive grass-weeds, with excellent crop safety.
He trialled a hectare of the system in year one, and was reasonably pleased with the result.
“The technology is more expensive relative to the alternatives, and we found that there was a slight yield penalty with the variety, so we’re using it in a very targeted way, in fields that have weed beet, to solve this specific problem,” says Mike.
“One of the benefits of Conviso Smart should be fewer herbicide sprays, but because the fields with and without weed beet problems are often next to each other, we have ended up having to make more trips with the sprayer. So, that adds to the cost, as well as the yield penalty. However, the technology is really good, and I’ve been impressed by the results on weed beet.”
When it comes to his fungicide programme, Mike is planning to make some changes.
While Escolta will continue to make up the backbone of disease control, he is planning to add in some other chemistry.
“I do have concerns that the choice of sugar beet fungicide is very limited, and therefore there is a risk of driving resistance. We will be looking to broaden the chemistry and modes of action in the products we use, as part of a resistance management strategy,” says Mike.
In terms of timings, the first fungicide spray is likely to take place during the third week in July, with the second spray following four weeks later. The need and timing of any third spray will be driven by disease pressure and the state of the crop.
“If the crop is looking strong and healthy, and I want to delay lifting until after Christmas, then it may get a third spray to keep the canopy clean for as long as possible,” concludes Mike.
