RE:RE:RE:KevinPotatoes aren't a broadacre crop, but grains are if you read the article below, and the nr says PK and CA are for broadacre crops.
The first PK nr listed 4 grains that PLAN is doing greenhouse trials on.
PK are phosphorus and potassium. "
CARBON PK is PLAN's first broadacre fertilizer so for sure CA is a calcium fertilizer additive. . https://seeingthewoods.org/2013/08/14/potatoes-and-the-foods-of-the-poor/
"..
main source of carbohydrates in the diet was wheat. This was a broad acre crop, sown by men guiding ploughs that were drawn by horses or oxen. But in South America, there was no comparable broad acre crop, because there were no draft animals " If you read the bottom of this article, it seems spuds can't respond well to calcium corrections because the tuber and roots are low in auxium, so unless PLAN's calcium has special properties, it will never be for anything but broadacre crops.
https://levitycropscience.com/how-to-improve-potato-quality/#:~:text=Improving%20Potato%20Quality%20is%20directly,bruising%20and%20post%2Dharvest%20diseases.