Potato Review

www.potatoreview.com POTATO REVIEW MAY/JUNE 2020 23 BIOSTIMULANTS Increasing soil nutrient availability with rhizosphere inoculants The concentration and diversity of microbes that is found in and around the roots of healthy plants is typically much greater than in the rest of the soil. The roots provide sustenance for these microbes through release of nourishing exudates. In return, these same microbes promote plant growth directly by either facilitating resource acquisition or stimulating the useful production of plant growth hormones. Enhancing natural metabolic processes and tolerance of stresses with plant biostimulants Plant biostimulants can be either microbes or their derivatives, which stimulate a range of useful natural processes. They increase nutrient uptake efficiency, enhance tolerance of abiotic or biotic stresses and improve crop quality. Preventing plant diseases and pests with biopesticides Microbes can be used as biocontrol agents preventing proliferation of plant pathogens and other pests. The incidence and severity of such challenges can be reduced through direct effects such as parasitism and/or disruption of crucial systemic functions. In addition, microbes with antifungal activities compete against pathogens by rapidly colonizing aerial plant parts and roots, using most of the available nutrients, and thus making it difficult for pathogens to grow. “The microbes have a symbiotic, or mutually beneficial, relationship with potato plants. They make phosphorus more available through solubilising this essential nutrient, which can often be less available than it needs to be, and this helps start young plants off well and encourages continual root growth in older plants,” he said. He said a microbial bionutrition product developed by Lallemand has increased tuber yields by an average of 7% in more than 30 trials carried out across Europe. The product, Rise™ P DualTech, is a root inoculant based on Bacillus amyloliquefaciens strain IT45. A plant growth promoting ‘rhizobacteria’, the Bacillus amyloliquefaciens strain IT45 is a living organismmade up of a minimum of 2 billion spores per gram, said Andrew. The ‘Rise’ product is mixed with water and applied at a rate of one kilogram per hectare, which equates to at least 2 trillion spores per treatment. It also increases the bioavailability of trace elements - especially iron - which help to improve plant growth and health as well as the production of certain plant hormones that are crucial for ideal growth, Andrew said. “Once the crop plants are better nourished, they will be considerably more productive. However, the plants can be prone to not retaining all of the tubers that they initiate and this is often exacerbated by external stress effects acting on the crop. To stop this happening, we recommend the use of a stress-relieving biostimulant product, such as IntraCell, afterwards,” he said. “For the seed, salad and early potatoes market, the main priority regarding performance is the number of tubers achieved. Our potato programme has a strong impact on reducing tuber abortion and consequently the end result is an increase in the number of tubers.” “The microbes have a symbiotic, or mutually beneficial, relationship with potato plants.” Andrew Gough, Lallemand Plant Care