Potato Review

www.potatoreview.com POTATO REVIEW MAY/JUNE 2022 37 BIOSTIMULANTS / FERTILISERS Good impact on salad potatoes Sam Brown , Technical Director at The Crop Smith Ltd, a new company developing and manufacturing biostimulants in the UK, reports on recent trials and findings. G LOBALLY, agriculture is facing enormous challenges. Farmers and growers are charged with raising productivity in order to feed the growing population and yet, at the same time, they are being asked to reduce their use of synthetic inputs. It’s now clear that, as useful as they have been, pesticides and fertilisers have had a detrimental impact on the environment and all of those who live in it, including us. So, what is the alternative? Perhaps replacing these synthetic inputs with a new class of organic, sustainable and effective products would be a great proposition? Natural plant biostimulants have been shown to improve all aspects of crop production from growth and development to flowering and fruit set, final product quality and of course, yield. But the uptake in the UK has been slow, so why is that? The interest in the use of biostimulants and biopesticides continues to grow, as they offer environmentally sustainable solutions for agricultural production. And the research to support the positive effects of biostimulants has ballooned over the last two decades, but most of this research has been carried out in regions of the world that do not resemble our UK climate and on crops that we do not grow on a field scale in the UK. Currently, there is very little independent, open access trial research which is directly relevant to UK farmers. The last review of biostimulants on cereals and oilseed rape in the UK was conducted back in 2016. This study was a thorough review of existing UK data, which was pretty thin on the ground back then and remains so today. To add to the confusion, biostimulants are an eclectic bunch of products with different modes of action. In the 2016 study, AHDB classified the products into 11 different subclasses: Seaweed extracts, humic substances, phosphite and other inorganic salts, chitin and chitosan, antitranspirants, protein hydrolysates and free amino acids, non-essential chemical elements, complex organic materials, plant growth promoting bacteria (PGPB), arbuscular mycorrhizal fungi, non-pathogenic fungi and protozoa and nematodes. Surely any farmer or agronomist would be hard-pressed to find the right biostimulant for the job in hand, in the face of such complexity? What is needed is a UK-based body of work demonstrating why, when and how to employ biostimulants effectively. In a recent replicated, randomised trial in salad potatoes (S. tuberosum cv. ‘Charlotte’) The Crop Smith Ltd. demonstrated increases in tuber size and overall yield using different classes of biostimulants in a programme of foliar applications. The biostimulants were combined into two products: CS1, a straight seaweed extract uniquely manufactured to be high in bioactive compounds; and CS6, a blended seaweed extract balanced with humic acids and phosphite. CS6 was used early on as it is designed to promote rooting and early crop establishment. CS1 took over later in the season when the crop was facing biotic and abiotic stress from pests and diseases, drought and high temperatures. The products were applied at regular intervals as foliar sprays throughout the crop cycle, starting with low applications of 1 litre per hectare and increasing to two litres per hectare as the season progressed and the canopy closed. Total application by the end of the trial was 12 litres per hectare. The results demonstrated a 14% increase in mean tuber size and an overall yield increase of almost 8%.