No guest speaker this month!
SPEAKER`S REPORT JULY 2025
Our speaker this month was David Llewellyn, an agronomist, which is someone who specializes in soil management and crop production, advising farmers on how to improve yields, protect crops, and manage land in a sustainable way. Agronomists apply scientific principles to various aspects of farming, including soil health, nutrient management, pest and weed control, and water conservation, ensuring compliance with regulations while optimizing farm profitability.
David specializes in brassicas, alliums and potatoes and our talk was focused on potatoes. 375 million metric tonnes of potatoes were produced in 2023 with China being the highest producer, accounting for roughly a quarter of global potato output, followed by India, Ukraine, Russia and the US. However, these countries do not optimize agronomic practices and the environmental impact of potato cultivation is large. The UK produces approx. 4.7 million tonnes of potatoes annually.
There are basically 2 avenues of potatoes – those you buy in bags and sacks, and those that are processing varieties, e,gused for frozen chips. Potatoes are harvested in the autumn and stored at 4 – 8 degrees in cold storage. Potatoes that don`t fit the size required by supermarkets are dumped! Only a few varieties can be found in shops and we`d only heard of 3 varieties from the list that China grows.
20 years ago, the ground for potato growing was stripped of everything and pesticides and fertilizers added. These days it`s not quite so bad, with producers using half the amount of fertilizer previously used. Big producers spray every 7-10 days, using 29 different chemicals! Crops can be sprayed up to 20 times before they are harvested. Yields are tested for residue levels and they have to be almost non-existant.
Blight can be a big problem, in fact this is one of the worst years for blight – it`s airborne and gardens and allotments carry it. There are different strains of blight and spores can last in the ground for 18 months. Blighted foliage should not be added to compost heaps. The varieties King Edward and Maris Piper don`t suffer from blight.
There are various potato diseases, wireworm being number one. Slugs can also be a problem, as can potato nematode, the solution to the latter being not to grow potatoes at all. The Colorado potato beetle is a notifiable pest and all gardeners are urged to keep an eye out for them.
David`s talk was fascinating and we learnt a lot about potato production and what is being done to maximise yields while ensuring that sustainability and the environment are carefully considered. Many thanks to David for his time, and to everyone who attended. There is no speaker in August due to the staging of our annual show so we’ll see you in September!