Great for clover fields.

What does fertilizer "analysis" mean?

All fertilizers have three numbers on the label which indicate the fertilizer analysis, or "percentage by weight" of nitrogen, phosphorus and potassium, in that order.

Therefore, a 50 pound bag of fertilizer labeled 20-10-5 would contain 20% nitrogen (10 pounds), 10% available phosphates (5 pounds), and 5% soluble potash (2.5 pounds).
See the calculations below:

50 pound bag of 20-10-5 fertilizer:
20% nitrogen (.20 x 50 lbs = 10 lbs)
10% available phosphates (.10 x 50 lbs = 5 lbs)
5% water soluble potash (.05 x 50 lbs = 2.5 lbs)

50 LB. Bag