It’s true in many circumstances. On a recent video segment from AgPhd, put out by Hefty Seed Company, The Heftys break down the amount of fertilizer per acre applied by farmers and homeowners; homeowners are usually adding too much fertilizer to their lawns. That excess fertilizer can drain off of their lawns and harm the environment by getting into rivers and lakes.

When you break it down, the amount of chemicals soil can hold is called its cat ion exchange capacity, or CEC. A soil’s CEC rating can be found by running a soil sample. Multiply that CEC rating by 10 to find out how many chemicals an acre of soil can hold.

In layman’s terms, homeowners add nitrogen to their lawns in spring. If their CEC is 15, then 150 lbs of nitrogen can be added to one acre. Many people buy a 20 lb bag and use it on a tiny yard that can only hold one tenth of what they add.

CEC Rating * 10 = Capacity of Chemicals Per Acre
 

Farmers use many soil samples to determine how many chemicals their soil can hold. If they add too much herbicide in the spring, that soil won’t absorb other fertilizers later resulting in a waste of money.

Farmers are often blamed for hurting the environment by polluting waterways with fertilizers while really, paying attention to a soil’s CEC rating is everyone’s responsibility.

- Colvin