Role of Calcium in Potato Production

Calcium and IRS

Internal disorders such as IRS (internal rust spot or internal brown spot - IBS) can be reduced by a good calcium supply, in the form of calcium nitrate, at ridging or during tuber initiation. Experience shows that ensuring there is a minimum of 0.15% calcium in the peel, improves potato skin finish, boosts disease tolerance and minimizes IRS (Russet Burbank, USA).

Calcium effect on soft rot

Strengthening the tuber cell wall with calcium can help reduce the severity of Erwinia soft rot in storage.

Calcium and skin blemishes 

Calcium also reduces the level of tuber skin diseases including black scurf and powdery scab leading to better skin finish. But high levels of free calcium in the soil, e.g. from recently applied lime, may increase the level of common scab (UK trials).

Calcium uptake by variety

High levels of calcium in the tuber also reduce bruising risks at harvest and subsequent transportation. Varieties vary in their calcium uptake, as USA studies show.

Calcium nitrate and bruising

Using calcium nitrate rather than ammonium nitrate minimizes bruising damage. In some varieties, damage can be halved.

Calcium and potato yield

The use of calcium in crops grown for seed boosts the following crop’s performance. A mother tuber enriched with calcium is faster growing and in better condition, thereby boosting yield per plant.

General guidelines for calcium application

Calcium is a key component of cell walls, helping to build a strong structure and ensuring cell stability. Calcium enriched cell walls are more resistant to bacterial or fungal attack. It is critical during cell division and expansion, and is therefore essential prior to, and during, the rapid growth phase of tubers.

Calcium also helps the plant adapt to stress by influencing the signal chain reaction when stress occurs. It also has a key role in regulating the active transport of potassium for stomatal opening. It is particularly effective at helping reduce summer heat stress, minimizing wilting and leaf damage. Where this happens, yield improvements of 30% have been recorded.