EFFECT OF NITROGEN, PHOSPHORUS, AND POTASSIUM ON YIELD, PERSISTENCE, AND NUTRIENT CONTENT OF TIMOTHY

Abstract

High levels of both N and K from fertilizer were required to obtain optimum yield of timothy and also to maintain timothy as the dominant species in a grass sod. Phosphorus was required in relatively small amounts. Timothy degenerated when an imbalance of N and K was induced through fertilization and did so most rapidly when N was applied without K. Increasing N applications generally increased N content but the extent of the increase was modified when K was also applied, similarly K application increased K content but levels were modified downward when N was also applied. P content was affected only slightly by P application but levels were lowered when yields were increased by a combination of N and K. Critical nutrient concentrations of 1.6, 0.20, and 1.2% for N, P, and K respectively were determined for first-crop timothy cut at the fully headed stage. Higher levels of N and P were observed in second-cut material.