Potato Review

www.potatoreview.com POTATO REVIEW MARCH/APRIL 2023 41 CUPGRA “We are still on a learning curve and best practice for application still needs to be re ned,” he emphasised, adding that development work now has to be done commercially, which can put the crop at added risk. Adrian, who formerly worked for AHDB Potatoes, said not everyone is trying out the more recently-approved sprout suppressants. Spearmint oil was approved 10 years ago, and quite a number of store managers are happy to continue using it as a stand- alone sprout suppressant in cold stores. Cost is a big factor in storage this year. A number of growers are looking at using orange oil because of its lower price. “Another way of keeping costs down is to ensure conditions for application are optimal to ensure the products applied are e ective for longer, which will help to avoid expensive re-treatments,” said Adrian. DMN, spearmint oil and orange oil are all applied as a hot fog, so fans should be run before and during application and stores closed for at least 24 hours afterwards for the best e cacy, he said. ere were also store managers who are content to use very cold temperatures for varieties with longer natural dormancy despite the rise in energy costs, he said. Adrian was pleased to discover that about two thirds of the growers reported using MH, which provides useful residual control of sprouting. “ is shows that MH is now accepted as an important part of the toolbox because it provides continuity of sprout control in storage, and also during shelf life.” Others are trialling di erent combinations, which is a move partly driven by the 30-day withdrawal period for 1,4DMN, and will be particularly important in long term storage. Crops treated with volatile chemicals such as spearmint oil and orange oil can be used sooner, although it is recommended there is a gap of up to 12 days before sale. “We have been talking to people in the US who have a number of years of experience of 1,4DMN under their belts, and they have emphasised the importance of using fans to dry the crops and manage any temperature di erences. “ is is something that will need attention to detail when applying this sprout suppressant and we need to have everyone on the same page when it comes to preparation prior to application. ere is work still to be done on evaluating whether better performance can be gained from combining the di erent actives, particularly when conditions are not optimal.” Adrian said spearmint oil and orange oil can be used in conjunction with MH, but when eld conditions have made it di cult to apply MH, there may be instances where burning the sprouts o with one product and then using another for longer dormancy is the way forward. “ ere are now a number of di erent options and many growers still need to get fully up to date as we develop best practice and become familiar with the advantages and disadvantages of each one.” Addressing environmental issues Dr Elizabeth Stockdale, Head of Farming Systems research at NIAB, brought together a range of published research to highlight that eating more potatoes is amongst dietary changes in Europe identi ed as an important means of reducing greenhouse gases (GHG). GHG emissions from food systems are approximately 33% of the total emissions in the world. However, root crops lead to just 3% of the food system GHG, and while CO2 is emitted during farming, using inputs judiciously – such as precise and targeted use of N fertilisers - can reduce waste and help minimise emissions. Although there are only a small number of studies that have collected data on GHG emissions in potato crops, Elizabeth encouraged growers to look at the range of options known to reduce GHG emissions in growing systems. is could include minimising tillage and reducing destoning depth in the eld, improving N use e ciency and integrating cover crops across the rotation. ere are also opportunities to improve the energy e ciency in potato stores, by reducing leakage and optimising insulation, she said. “ e more e cient you are, the lower the relative carbon footprint.” NET ZERO WHAT PEOPLE ARE TALKING ABOUT AND WHAT IT REALLY MEANS NET zero does not mean that we will have no greenhouse gas emissions at all, said Elizabeth. It is a zero balance point where any emissions that remain in the system are balanced out by sequestration, in trees, hedges and soil, she explained, adding that talk often focuses on carbon and carbon footprints, but amalgamating all the data in this way can mean we miss the relative importance of emissions of methane, and nitrous oxide and hydrocarbons. GHG emissions within the direct control of the business and its energy use are considered Scope 1 and Scope 2 emissions respectively. But businesses are also accountable for the GHG emissions associated with the inputs they use and their products (so-called Scope 3 emissions). In the context of the potato industry, GHG emissions during the growing of the crop are considered as part of the GHG emissions of the processing and retail sectors. FOOD SUPPLY CHAIN CHALLENGES • CO2 Redesign cropping systems on lowland peat • CO2 Use renewable energy where possible and minimise cultivations • N2O Optimise use of N inputs in fertiliser and manure • Optimise energy use for activities such as storage, packaging, waste • CH4 Optimise waste management • Make use of carbon storage opportunities • Grow the bio-economy Graham Tomalin of VCS Potatoes. Sarah Roberts of NIAB CUF.