Potato Review

22 POTATO REVIEW JULY/AUGUST 2021 FERTILISERS T HE organic sector and its suppliers continue to develop an increasing number of natural solutions. Some growers are already looking at products that help the plant defend itself naturally or withstand stress factors more e ectively, and global pesticide manufacturers are now bringing ‘natural’ products to market. But getting the soil and its nutritional value up to scratch from the beginning is still the priority. A plant with the perfect balance of nutrients both for initial development and longer season growth is key to a plant being at its best and giving itself the chance to defend itself against the array of challenges it will experience in its growing cycle. Agronomist Peter Saunders, of Cambridge Natural Solutions based in March, is keen to stress how valuable crop nutrition is in a ecting pest or disease susceptibility. “Plants contain desirable food sources for pest and diseases, which is why they choose to attack particular species of plants, but these food sources can vary in their availability to the attackers. If the food source is harder to access, the pest or disease is less likely to establish,” he said. Natural Solutions Experts share their tips and insights on organic fertilisers. “ e plant’s rst line of defence is its cuticle and leaf wax and the strength of this outer defence layer is dependant on the correct balance of available nutrients.” For example, several nutrients play crucial roles for cell wall strength, but if these are unbalanced and the cell walls weak, sugars, amino acids and small sizemolecules can leak into the intracellular spaces and hencemore readily available to sucking insects and fungal hyphae Several companies around the world have also developed elicitor compounds which stimulate the plant tomake a biochemical response to a potential or actual pest attack. Cambridge Natural Solutions develops molecular compounds to encourage genes to start chemical defencemechanisms. However, if the plant lacks the basicminerals to produce chemicals then the plant cannot defend itself. Pete said: “Many basic farmpractices can in uence disease protection fromnot over applying nitrogen, especially not in one dose, to pesticide applications and tankmix combinations that strip the leaf of the waxy protective layer.” Improving rooting and using varieties with good disease resistance are alternative cultural mechanisms that can improve plant health. “Achieving a consistent nutritional supply across the field when applying them is challenging.” John Limmer, Agronomist, HZPC It is important for farmers to consider more sustainable, cost e ective and environmentally friendly solutions to crop production challenges in the future, he stressed. Accurate nutrition supply Organic manure is a hugely valuable asset when used in the rotation, but where seed potato crops are concerned, any nutritional inconsistency can present a logistical headache when trying to manage crop desiccation. HZPC’s technical support and company agronomist John Limmer said he uses OMEX suspension fertilisers to give an accurate supply of nutrition for the crop as he believes their bespoke nature helps maintain an even crop, which is essential for aiding the desiccation programme to maximise the crop in the desired size fraction. Dutch company HZPC has signi cant interests in the UK, mainly in Scotland, Yorkshire, and the Cotswolds, where more than 30,000 tonnes of seed potatoes are John Limmer, Agronomist, HZPC