Spring is a good time to fertilize grass pastures. They need adequate fertility to produce well. A soil test is your best guide to amounts of phosphate (P₂O₅), potash (K₂O), and lime that may be needed. Nitrogen (N) is the primary nutrient needed for grasses and rates depend on the type of grass in the pasture.

Bluegrass pastures can benefit from up to 80 lb./acre of N. Tallgrass pasture crops (brome, orchard, etc.) perform well with applications of up to 120 lb./acre of N. April is a good time to apply N to these cool season grass pastures. The suggested N rate for warm season grass pastures (switchgrass, bluestem, etc.) is 90 lb./acre. Early to mid-May is suggested as a time to apply N to warm season grasses. Both dry and liquid N can be used on grass pastures. Some N loss may occur due to volatilization from fertilizers that contain urea.

Adding P₂O₅ or K₂O is recommended only when test levels are in the very low or low range. If P test levels are in those ranges, apply 60 to 40 lb./acre of P₂O₅. When K tests are very low to low, apply 80 to 60 lb./acre of K₂O. A soil pH of 6.0 or higher is adequate for grass pastures. Add lime only when the soil pH is below 6.0. When lime is topdressed, add only one-third to one-half the amount recommended for a tillage or sample depth of 6 inches.