Key nutrients for high-performing potato crops
3rd May 2023
Nutrient deficiency is a widespread issue in potatoes grown in the UK and can lead to internal and external crop damage with associated financial losses. To help farmers maintain adequate nutrient levels in potato crops, Oscar Thacker, area manager at Yara, offers some advice.
According to Mr Thacker, the four key micronutrients supporting healthy potato crop growth and formation are potassium, nitrogen, phosphate, and calcium.
“Both nitrogen and potassium are key for vegetative growth, tuber formation, and bulking, but potassium in particular is required in large quantities,” he said. “A 38.5t/ha crop can remove more than 120kg/ha of nitrogen whereas it can remove over 200kg/ha of potassium.”
Both nitrogen and potassium are recycled from leaf to the tuber during bulking, with the latter being vital to high yields and maintaining tuber integrity. Alongside potassium, phosphate is also required in relatively large quantities during early growth.
Meanwhile, calcium plays a key role in soil pH and achieving those all-important quality parameters, but is often deficient in UK soils.
Mr Thacker added: “Potatoes need calcium to strengthen the skins of the tubers, providing a better skin finish and better resistance to many diseases including black scurf, silver scurf, and common and powdery scab.”
Calcium deficiency is also a common cause of internal rust spot, further highlighting the importance of applying the right source of calcium at the right time. Therefore, growers should make sure their product of choice offers a plant-available source of calcium.
“Many growers apply liming materials to the soil, however, they won’t provide plant-available calcium to the crop and therefore it won’t provide sufficient supply to meet the demand,” Mr Thacker pointed out. “Calcium nitrate, such as YaraLiva Tropicote, provides soluble calcium that is plant-available, unlike the liming materials.”
He also suggested saving some nitrogen from the seedbed application to use for the calcium nitrate dressing, which provides the potato crop with the right soluble calcium.
