Potato Review

48 POTATO REVIEW MARCH/APRIL 2021 FERTILISATION A S pressure mounts on potato growers to reduce on-farm emissions, protect groundwater and regenerate soils, many will be seeking options to make their farming practices more sustainable. Some growers, however, may feel wary to opt into stewardship schemes and change the way they farmbecause of worries that they will have to sacri ce their yields or increase their farmcosts. Despite this, recent trial work has shown that yields and quality can bemaintainedwith the use of some environmentally-friendly products. Technical SalesManager at Agro-Vital UK, Carl Gibbard, said fertilisation choices are key. “ e healthy establishment of potatoes has signi cant e ects on the nal yield a grower can achieve, so delivering nutrients to the plant at the right time is incredibly important for the success of a potato crop,” he said. “Because of this, growers will put a lot of consideration into the nutrients they apply to their potatoes andwill choose fertiliser based on previous results of what gets the job done e ectively and economically.” However, nutrient uptake is often limited if fertilisers are applied in sub-optimal conditions, andwhen over-used, this can have negative e ects on the environment, such as phosphate contaminating watercourses, Carl added. To combat this, he suggests growers should evaluate the nutritional e ciency of fertilisers they apply on-farmas this process could be a step in the right direction to help reduce environmental impact. Granular and liquid fertilisers Carl said granular salt-based fertilisers are traditionallywidely used, but are oftenused at high volumes and canbe prone to leaching or volatilisation andwill damage the delicate balance of soilmicro-organisms. On the other hand, liquid placement fertilisers, such as P-Focus, provide nutrients directly to the seedwhich are readily takenup by the roots during establishment. He said thismaximises the solubility of nutrients and provides an e cient source of N, P and K, with a low salt index. e formulation of phosphate (P2O5) within Nutritional e ciency Use of smarter fertilisers is recommended to reduce environmental impact and maintain yields. this fertiliser is signi cant as it is an essential nutrient potato crops need for root establishment, but uptake of thismineral is often limited from traditional rock phosphate fertilisers as it’s commonly immobile in soils. “Rock phosphate in the soil is largely unavailable at plantingmeaningmany growers will need to apply it in large quantities but this can lead tomany water catchment areas polluted with phosphate from run-o ,” said Carl. Increasing availability of phosphate through the use of smart fertilisers can have positive impacts for the environment. Agro-Vital’s recent trials have indicated that liquid placement fertilisers can have positive impacts on ‘both potato yields and the environment bymaking phosphate readily available to the plant. Trials In collaborationwith Oxford Agricultural Trials (OAT), Agro-Vital carried out trials in 2020 to investigate how replacing all or part of a farm standard fertiliser programme with smart products would impact yield and quality. is particular trial focused on the e ciency of the smart liquid fertiliser P-Focus onMaris Piper potatoes andwas carried out at Stratton Audley inOxfordshire. “We know the environmental bene ts of P-Focus, but in this trial, wewanted to understand how this liquid fertiliser fares against the farm- standard triple super phosphate (TSP) that is commonly used by potato growers,” Carl said. In the trial, the TSP and P-Focus were applied at planting. e results showed no signi cant di erence in yields from the plots grownwith the farmstandard TSP and the liquid fertiliser, but the total amount of phosphate used to generate each tonne of potatoes was drastically reducedwhen using the liquid starter fertiliser. In the farm-standard TSP plots, 3.56 kg/ha of P2O5 was required for each tonne of yield. Whereas the potatoes grownwith P-Focus liquid fertiliser only needed 0.28 k/ha of P2O5 per tonne of yieldwhich shows a signi cant reduction. “ is shows the e ectiveness of smart liquid fertilisers as they deliver the required nutrients potatoes need at the right time to produce high quality yields. “ e need for high-volume applications of fertilisers is reducedwhen such fertilisers are used as the liquid starter fertiliser can be placed directly onto the seed potato, so uptake of nutrients increases, saving growers time andmoney on fertiliser applications,” he adds. By reducing the granular salt-based fertiliser products and replacing themwith smarter placement and foliar fertilisers, e cient and timely crop nutrition, can be achieved with hardly any leaching, volatilisation and no scorch or seed damage. “With the growingmarket pressures that farmers face, adopting sustainable technology such as this could help the sector reduce environmental impact without sacri cing farm success,” Carl said. The reduction in phosphate required per kg/ha to produce a tonne of yield when using alternative fertiliser products