When we think potato fertility, how many of us would think of calcium in the first three important nutrients? What about top 5? Are we thinking about it at all? Would it surprise you to know that calcium is a critically important nutrient in potato production? Calcium is involved in many physiological functions such as cell division, cell wall integrity, water regulation and stress signaling. These functions improve the plants' response to heat stress, reduce disease and improve quality of the tubers, but not just any old calcium source will do.
Potatoes are a cool-weather crop and when they experience hot, dry conditions, the tubers will be negatively impacted both in quality and size. Calcium is important in the active transport of potassium to regulate stomatal openings. If calcium is low in the plant, the signal for potassium to close the stomata may be slow and the plant will lose precious moisture through transpiration. Calcium is taken up by the stolons with water and moved up the plant through the xylem where the water will eventually transpire through the leaves. This is how calcium will accumulate in the leaves to prevent foliar damage from heat stress.
Temperature stress can induce Brown Center/Hollow Heart
Calcium is important for the proper development of cell structure and rigidity in the tubers. It is required throughout the season, but there are certain growth stages where it benefits the plant most. If calcium is not available during tuber initiation or bulking, the cells may degrade and cause physiological disorders such as internal brown spot, hollow heart and bruising. This is important to potato producers as they may get paid less for their crop that show signs of these disorders.
As calcium is taken in through the stolons, it will integrate into the cell walls that require it the most and cannot be redistributed to new cells as they are formed. This is why it is critical for potatoes to have access to available calcium through the stolons throughout the season. A deficiency will see a collapse and degradation of cells, known as soft rot.
Calcium only moves up the plant which means a foliar application will not be available for tubers to take in. Incorporating calcium into a fertigation program or applying a granular source at re-hilling is the most effective way to ensure the tubers have access to available calcium throughout the tuber initiation and bulking stages.
Many soils contain adequate amounts of total calcium, but most of the calcium is tied up in insoluble forms such as calcium carbonate or calcium sulphate and there is very little soluble calcium, the only form of calcium that is available to potatoes. Soluble calcium such as calcium nitrate is the most effective at getting into the plant as the nitrate-nitrogen improves plant uptake of cations. YaraLiva® CN-9® is ideal for fertigation applications and provides nitrogen and calcium immediately available for plants. YaraLiva® NITRABOR™ is a granular calcium nitrate option for areas that do not use irrigation.
Solubility of Calcium Sources
Visit yaracanada.ca/calcium-nitrate-for-potato to learn more about calcium nutrition for potato crops.