soils question

[Terri]

Is there any reason to know the Cation Exchange Capacity?

OK, I know that a high CAC is better, but my land is what it is. Will knowing the CEC be of any practical value?

My soil is neutral sandy clay, with a PH of about 7, and it grows good grass (as does most of the midwest!). I am interested in raising some veggies, and so I am looking to fertilize it. The soils out here are almost a little low in NPK, and so is mine. But, will knowing the CEC help me any?

Thanks!

[hillsidedigger]

The addition of organic matter can raise the CEC but might increase the acidity which can be fixed with (small amounts, lime is natural) of lime and maybe bone meal.

Minerals added to low CEC soil leach away rapidly.

[Cabin Fever]

CEC is just a measurement of the ability of soil to retain (ie, keep from leaching) cations. Many fertilizer elements are cations (potash, calcium, magnesium, ammonia, etc). It's harder to change the pH of a soil with a high CEC.

[Terri]

So, if it has a higher CEC, then the fertilizer lasts longer, as opposed to washing away during the next rainfall?

Should the fertilization schedule be changed to reflect the CEC?

[Cabin Fever]

As a soil scientist, I do not believe in a “fertilization schedule.” I recommend fertilization based on soil test results.

[Terri]

Thanks!