Amounts
of some nutrients removed by harvesting over
a 50 year period compared with weathering release
of nutrients in temperate areas (kg/ha)
50-500
150-1500
250-1000
5-25
Weathering Rates
500
550
2000
1200
Corn-wheat-soybeans
25-100
175-250
60-150
10-20
Deciduous Forest Harvest
Mg
Ca
K
P