Potato Review

18 POTATO REVIEW JULY/AUGUST 2020 TUBER QUALITY “ e cell wall is often called the “skeleton” of the plant,” said Mark. “You also have a cell membrane just on the inner side of that cell wall. Combined, these keep the rigidity of the tuber in the plant, and allow water, nutrients, and products of the various reactions to move in and out of the cell and around the plant. Our foundation should be about creating a high-quality cell wall and cell membrane.” One step towards this is proper levels of hydration. Potatoes that are hydrated adequality are less prone to damage by starch grains within the cells and are also less likely to su er from internal black spot. However, it’s important not to go too far in the other direction; over-hydration can result in growth cracks and lower overall dry matter. In terms of nutrients, Mark identi es three key nutrients that often go undervalued: “We are all guilty as farmers and agronomists of focusing in on NPK – and rightly so – but other nutrients like calcium, boron and potassium all play an essential role in forming strong cell wall structures and integrity.” Calcium is intrinsic to cell wall formation. Speci cally, calcium promotes strong cross- linkages between pectin molecules which ultimately give the cell its rigidity, reducing the chance of rupture. is composition is sometimes described as the “egg box” structure. Calcium de ciency will cause several issues in the crop, including poor skin nish, lower internal quality, bruising, and storage rot. “It’s an essential nutrient,” says Mark. “Calcium is a prerequisite for good crop development. It should be applied at about 50kg Ca/ha.” While calcium is vital, equally important is its source says Tom DeCamp, Area Manager at Yara. “Solubility of calcium sources is a critical feature when absorbing calcium,” says Tom. “Most lime products are in the form of calcium carbonate, which is not very soluble. Calcium nitrate is the preferred option, making the calcium and nitrogen both instantly available to the plant.” Boron has also been identi ed as a critical element for tuber development, with up to 90% of the cellular boron located in the cell wall. Without it, degraded and blackening cells are observed, demonstrating its use in forming the pectin binding that results in overall stability within the tuber. Potassium, too, should not be overlooked. As an osmotic ion, Potassium serves to control water movement in and out of the cell. is controls what is called “turgor pressure”, reinforcing the cell and making it less prone to mechanical damage. When seeking to ensure high quality in potato growth, always prioritise cell wall integrity. Key to that is an e ect nutrient management programme – but do not overlook calcium, boron or potassium, as these all play a vital role, Mark and Tom both advised. “It’s important to make sure the right things are getting to the plant at the right time,” said Mark. “Timing your application carefully and using a soluble calcium nitrate can, when used as part of a robust nutrient programme, promote robust health and better quality for your potato crop.” “Solubility of calcium sources is a critical feature when absorbing calcium.” Tom DeCamp, Area Manager at Yara “We are all guilty as farmers and agronomists of focusing in on NPK – and rightly so – but other nutrients like calcium, boron and potassium all play an essential role in forming strong cell wall structures and integrity.” Mark Tucker, Agronomy Manager Yara’s Area Manager Tom Decamp helped to answer questions on the role of calcium, benefits of using nitrates, tuber initiation and tuber analysis during a recent online seminar. Boron has also been identified as a critical element for tuber development, with up to 90% of the cellular boron located in the cell wall.