Do you know what the pH of your pasture is? 

A soil pH within in the range of 6.0 to 7.0 helps ensure optimal nutrient availability for pasture plants and promotes healthy growth. 

A soil test will show your soil pH and help you understand which nutrients are needed to meet yield goals. If you need to increase the pH of your soil (make it less acid), the SMP buffer test will help you determine how much liming material is needed. Ground limestone (calcium carbonate) or dolomitic limestone (containing Mg) are applied to maintain an appropriate soil pH.

Applying and incorporating lime into the root zone before planting a new seeding is most effective. Topdressing lime on the soil’s surface in established pastures primarily affects the top couple of inches of the soil profile, since it is not mobile in the soil profile. Note that legumes require a higher soil pH than grasses for optimal growth due to the requirements of the symbiotic relationship with Rhizobium bacteria that results in biological nitrogen fixation. Grass species can tolerate a slightly acidic soil (around pH 5.5), whereas many clovers such as white clover are more sensitive to acidic soil and will not grow well in soils with a pH below 5.8. Alfalfa is even more sensitive and requires a minimum soil pH of 6.2–6.5.

To learn more about liming your pastures, refer to Applying Lime to Raise Soil pH for Crop Production (Western Oregon) (EM 9057).