|Nutrient removal without replacement|
|Continuous cultivation requires nutrient replacement|
Many years of high-yielding crop production has resulted in a mining of this resource. For example, an alfalfa hay yield of 8 tons/A will remove about 500 lbs K2O each year. A 400 cwt/A yield of potatoes accumulates over 400 lb K2O/A in the plant! When high-yielding crops are continually harvested and removed from the field, the native potassium resource finally becomes depleted and exhausted. Even where some potassium-rich minerals remain in the soil, they frequently cannot release their nutrients at a rate to meet the peak demand periods of a rapidly growing plant.
|All plants require potassium|
|High-yielding Idaho potatoes|