Calcium is probably the third most important nutrient needed by brassicas. The nutrient ensures vigorous leaf, root and canopy growth. Supplies need to be maintained throughout growth to maximize uptake. Calcium also has a key role to play in maintaining crop quality. Even though the total calcium uptake of brassica crops is high, the quantity of it which is finally removed from the field at harvest is usually relatively low.
Manganese is required for chlorophyll formation and oxide-reduction reactions in cells, and increases vitamin C contents. It is also involved in the metabolism and synthesis of proteins. Crops that are well supplied with manganese have higher vitamin C contents.
Good sulfur nutrition leads to an increase in compounds known to improve human health. These include phenolic compounds and glucosinolates. Phenolic compounds - namely caffeic acid derivates and flavonols - have been linked to the reduction of chronic diseases and reduced risks of cancer. Glucosinolates, as well as adding to taste and improving a plant’s ability to resist stress, are also anticarcinogens.
Several studies have also shown that potassium supply increases vitamin C levels in the crop.