Can too much lime cause problems in your pasture?
It is a common expression among farmers that when it comes to adding soil amendments “You can’t use too much lime” but like many old axioms it turns out this one isn’t true.
While applying lime to depleted soil can seem to revitalize the first year after an application but by the end of the third year signs that something is radically wrong can start to appear. Basically the excessive amount of lime prevents the plants from drawing potassium and magnesium up in amounts sufficient for good quality and yield.
Adding calcium also helps to increase the pore space in soil, which is generally a good thing in pastures that have a tendency to become compacted. But if you create too much pore space your soil can dry out quickly and in areas where water is at a premium this can be a huge problem. Many soil scientists feel there is a correlation between the calcium to magnesium ratio in soils to the productivity of the soil. Graeme Sait outlines the importance of knowing your soil and allowing it to breathe:
“Soil breath is all about achieving the optimum ratio between calcium and magnesium in your soil and this, in turn, depends on the CEC of your soil. CEC is a measure of the clay component of the soil. A sandy soil might have a CEC of 4, while a heavy clay soil might have a CEC of 40. In the heavy clay soil you need more calcium to help push apart the high clay component. Here, the ideal Ca:Mg ratio might be 7:1. Conversely, in the sandy soil you might need a Ca:Mg ratio of just 3:1, because you need more magnesium to help create structure in a soil where there is none. In general, the closer you can move your particular Ca:Mg ratio towards ” ideal” for your soil type, the better you will do in your growing enterprise.”
Check out the rest of his article at this link
The effect of too much calcium from lime directly effects the availability of other elements in the soil and may cause a higher pH value. Soil pH is a measure of the acidity and alkalinity in soils. A pH of 7 is neutral. A pH greater than 7 is basic, and less than 7 is acidic. Grass forages perform well in soils with a pH between 6 and 7.
So what’s the best way to proceed? Not to sound like Johnny One Note but the answer is get a soils test and apply nutrients accordingly.
For more information take a look at Neal Kinsey’s blog