Potato Review

www.potatoreview.com POTATO REVIEW NOVEMBER/DECEMBER 2020 29 BIOSTIMULANTS H ERALDED as a means of reducing stress in crops, the jury is still out on the bene ts and limitations of biostimulants as a means of driving measurable improvements to marketable yields. Specialist potato consultant and former Head of NIAB CUF, Dr Mark Stalham, has been keenly monitoring the biostimulant trials undertaken over a number of years in the UK and abroad, and whether statistically signi cant di erences in yield and/or quality have been detected. Mark said: “ e key driver of potato yield is the expansion and longevity of the green canopy. is in turn depends on quality seed, good soil conditions, an adequate supply of water and the right nutrition. Crops can become stressed when one of these is compromised, and when this happens, people believe biostimulants may play a role in ameliorating damage to yield and/or quality.” BIOSTIMULANTS Specialist consultant looks at how better-informed decisions can be made on biostimulants. Biostimulants can work in a number of ways; including improving soil structure, releasing locked-up nutrients, stimulating the growth of mycorrhizal shoots and changing biomass partitioning within the plant. However, Mark said one of the challenges for growers seeking to use biostimulants is a lack of reliable data on a positive response from their application. Trials literature relating to how the data has been taken is often vague and frequently based around potato crops with low yields, rather than the high yields achieved by the best Northern European or US growers. In addition, many of the biostimulant trials Mark has seen have had high data errors. Well-conducted trials have a low coe cient of variation, which makes it easier to see any di erences, but there is still little convincing evidence showing positive bene ts in the eld. “The question is whether the improved soil structure increases uptake of resources and whether they are subsequently used to develop a better or longer-lasting canopy.” There is still little convincing evidence showing positive benefits in the field. Dr Mark Stalham, has been keenly monitoring biostimulant trials undertaken over a number of years in the UK and abroad. High yielding trials performed by Washington State University on non-traditional production additives’ showed that there was no statistically significant eect of any product on marketable yield. E ects on yield and quality of soil nutrient availability If nutrient availability is limiting yield because of soil compaction, one of the ways this may be addressed is by improving soil structure through the use of a biostimulant. “Better soil structure facilitates root development and increases water and nutrient uptake,” said Mark. e team at NIAB CUF have undertaken experiments exploring the potential of micro- algae to improve soil porosity. “ e question is whether the improved soil structure increases ➜