Potato Review

www.potatoreview.com POTATO REVIEW MARCH/APRIL 2023 21 T HE Crop Smith Ltd, which produces seaweed extracts and biostimulant products, recently processed the results from an on-farm trial in Norfolk with a large potato grower, which showed a 40% increase in yield following a biostimulants programme. e aim of this on-farm demonstration trial was to examine the e ect of a combination of CS1 seaweed extract and bene cial microbes on growth and yield in potato cropping. e work built on 2021 results after e Crop Smith Ltd carried out scienti c trials on ‘Charlotte’ which demonstrated a 13.93% increase in mean tuber weight and a 7.82% increase in yield per plant. e maincrop variety ‘Russet Burbank’ (which produces medium to large tubers that are long,cylindrical, and oblong in shape with a slightly attened appearance) was used for the latest trial in Norfolk. e application programme was as follows: • Treatment 1: Control = Standard Practice • Treatment 2: Standard Practice + Microbial application pre-planting and at tuber initiation + CS1 seaweed extract at 1 litre / ha every 10-14 days An interim assessment was performed in June 2022, at an early stage in the crop, to assess visible di erences between the untreated and the treated plants in the eld. Assessment of the foliage revealed a clear di erence whereby the treated foliage appeared darker and denser than the untreated foliage. is suggested a higher leaf area and an increased level of chlorophyll in the leaves of the untreated plant. Further investigation of the roots revealed that the untreated plants were at the hook stage but the treated plants were beginning to form small tubers. is suggests that the treatment had advanced the physiological stage of the crop. In principle, this should lead to the development of more tubers that are larger and heavier as tuber development will occur over a longer period in the crop cycle. A visual comparison was made with the nal tubers at harvest and a clear di erence was apparent. Randomised, replicated samples were taken from the trial areas prior to harvest in late September 2022. Technical Director Samantha Brown said: “ e results demonstrated a 13.76% increase in tuber numbers and a 27.83% increase in mean tuber weight which delivered an overall increase in yield of 40.42%. is extrapolates to an increase from 24 t/ha-1 to 34t/ha-1. Statistical analysis of the data con rmed the yield increase as highly signi cant.” Soil Biomass Assessment Immediately prior to harvest, soil samples from the untreated and treated plots were taken and sent to an independent laboratory to ascertain di erences in soil biomass. Increases in moisture content, bacteria, fungi and hyphal diameter were observed. Summing up, Samantha said: “ e application of bene cial microbes plus regular applications of CS1 results in an increase in yield in maincrop potatoes. In this case, a highly signi cant yield increase of 40%was observed. “It is probable that this result was also in uenced by local climatic conditions and the physical and chemical condition of the soil, meaning that results will di er from trial to trial as soil-plant biology is complex. “However, it is known that foliar seaweed extract applications increase chlorophyll content and photosynthesis, and also the level of exudates issued into the soil via the plant roots. rough this mechanism, seaweed extract application a ects soil biology at the soil root zone by increasing total microbial count and available soil nitrogen, and impacting microbial community diversity with an increase in microbial families linked to soil health. “A deeper understanding of the e ects of seaweed extract on the plant-soil ecosystem is required in order to improve future methodologies in sustainable food production.” In 2023 further trial work will be conducted by independent researchers examining the e ects of CS1 andmicrobial soil amendments inmaincrop potatoes and other important UK crops. BIOSTIMULANTS 40% yield increase seen in trial Promising results published following programme of biostimulants applied to maincrop potatoes in Norfolk. Tuber sample comparison at harvest – above is untreated and below is treated. Interim rooting assessment – the left side is untreated and the right side treated. About the variety e variety used in the trial has dark brown skin containing faint spots of light and is covered in russeting, which is a ne, sandpaper-like, rough, outer texture. Russets generally have few, shallow eyes. e esh is pale white, rm, dense, and oury and this cultivar is commonly grown for the frying / chipping industry in the UK.