A Cardinal number represents an equivalence class of sets between which there is a bijection (one-to-one correspondence). It is the number of elements in any member of the equivalence class. An Ordinal number represents an equivalence class of well-ordered sets between which there is an order-preserving bijection. It is the number of elements in any member of the equivalence class. The difference is only in whether the sets are ordered.
It is the basis for protein manufacture in plants and plays a major part in photosynthesis. For lawns, shrubs and leafy houseplants, a nitrogen-rich fertilizer is the best choice. When reading a fertilizer package, nitrogen will be the first in a series of numbers appearing with dashes between them. For example, a formula of 10-0-0 is a nitrogen-only fertilizer.
In the absence of a soil sample, it is best to use a fertilizer with a 3-1-2 or 4-1-2 ratio of nitrogen, phosphorus and potassium. Examples of fertilizers with these ratios are 12-4-8 and 16-4-8.These numbers tell you the percentages of nitrogen (N), phosphorus (P) and potassium (K), and always in that order (sometimes referred as N-P-K).ounding this number to six, you would apply six pounds of 16-4-8 fertilizer per 1000 square feet of lawn area. Using 12-4-8 fertilizer, you would apply eight pounds per 1000 square feet.