1) Fertilizer calculations (11-37-0)
a) 15 points 20 lb. P2O5 x .44 = 8.8 lb. P
b) 15 points 20 lb. P2O5 /.37 = 54.05 lb. fertilizer
c) 10 points 54.05 lb. fert x .11 = 5.95 lb. N

2)10 points each

Biological N fixation: biological conversion of atmospheric N2 gas to ammonium available to plants.

Industrial N fixation: atmospheric N2 gas is reacted with H2 under high temperature and pressure to form NH3

P fixation: any chemical change in soil P that reduces the amount that can be absorbed by plant roots.

K fixation: K is trapped in the interlayers of clay minerals and is no longer available to plants.

3)Nitrification---decreases pH

4) Nitrogen