Phosphorus and potassium, however, are critical to maintaining a productive stand of legumes. An annual soil test should be used to determine the need for phosphorus and potassium and will also indicate if there is a deficiency in micronutrients.

Legumes are more sensitive to low soil pH than are most forage grasses and, based on soil test recommendations, lime should be applied when pH soil values fall below 6.0.  Many of the annual clovers are also intolerant of high pH soils.  Most perennial clovers and the medics (including alfalfa) tolerate a fairly wide range of soil pH but are most productive when the soil pH is near neutral.

John Caddel, Forage Agronomist, 
Professor of Plant & Soil Sciences

john.caddel@okstate.edu