Carrot growers could boost their marketable yields by almost 20 per cent by adopting a comprehensive tailored approach to crop nutrition.

Although yields have generally plateaued over the past 20 years, independent trial results over the past two years have shown a massive 19.41 per cent increase in marketable yields over an already high-yielding crop. The trials, carried out by independent specialist NDSM in Yorkshire, compared standard best practice fertiliser inputs with OptiYield – a complete software package providing tailored nutrition and bio-stimulant recommendations for different soils and crops.

According to Nigel Metcalfe, managing director of NDSM, the randomised trials were replicated across five plots of 10m x 4 rows in both 2014 and 2015, hosted by a major national carrot producer in North Yorkshire. In 2014 the combined programme produced a 19.41 per cent increase in marketable yield, due to higher gross yields and fewer small roots. In 2015 that increase was 16.19 per cent, leading to a two-year average gain of 17.8 per cent.

In addition, the crops contained significantly higher levels of minerals and natural sugars, improving human nutrition, while also showing a 50 per cent decline in cavity spot. Furthermore, OptiYield delivered significantly higher yield gains than either nutrition or bio-stimulation alone.

“Over the past couple of decades, significant gains have been made in breeding and precision farming – yet yields have remained largely unchanged,” said Simon Fox, director of Emerald Crop Science, which developed the OptiYield programme.

“Crops need a balance of up to 14 nutrients, yet the industry still focuses on the three main fertilisers – nitrogen, phosphorus and potash. By running a detailed soil analysis through the computer programme we can pull together a unique, bespoke mix of nutrients and bio-stimulants to meet the crop needs, allowing growers not only to break through marketable yield barriers, but also to improve crop quality.”

Of course, adopting such a tailor-made approach costs more than the standard NPK practice, but the return on investment is considerable, he adds. “The OptiYield programme and products fit in with a farmer’s standard spraying plan, with the full programme costing about £175/ha – equivalent to about 1t of carrots. The trials produced a 14t/ha (19.41 per cent) increase in marketable yield of Nairobi carrots, to 89.05t/ha, on light sandy loam soils. At £160/t this would boost income by an estimated £2,240/ha and increase net profit by 63 per cent.”

Importantly, the programme has consistently produced similar results in commercial crops of carrots, leeks and potatoes – but growers should not view it as a wonder drug. “This is about another piece in the best practice jigsaw,” said Mr Fox. “It’s been developed through years of meticulous scientific research and backed up by trials, but you still have to get all the other aspects of soil and crop management right. The industry’s understanding of the soil, nutrient interaction and crop needs is improving all the time – producers just need to adapt their management to reflect that and benefit from it.”