That depends entirely upon the reason why he is infertile. If it is because he makes no sperm, there is no way to change that. Low sperm count can be fixed only by laboratory work to concentrate the sperm or for in-vitro fertilisation. Other problems can be fixed medically.
Yes
alfalfa
Men do not stop being fertile, Women stop when they pass though the "menopause".
Orientals are the least sexually active and least fertile. Blacks the most sexually active and most fertile. Whites are intermediate.
It makes the land more fertile
Organic matter.
well by doing the right thing.
ash and lava
Being hirsute has no effect on a males fertility.
makes land around it very fertile
the sperm finds a fertile egg and makes a baby
The reproductive system in both men and women becomes more active. In men the testis start producing more and fertile semen. In girls, the ovaries produce fertile eggs.