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Fertilizing Grass Pastures

By Jerrold Tesmer
Extension Educator, Fillmore and Houston Counties

Are you looking for ways to get more out of your pasture? Have you ever soil tested your pasture? Do you treat your pasture like a valuable crop?

As with other crops, adequate fertilizer is needed for optimal economic production. This might mean being able to increase the number of animals grazing a particular pasture or have pastures last longer into the summer or fall. Soil testing is particularly valuable for determining phosphate and potash needs.

Nitrogen is usually the first nutrient we think of for grasses and grass mixtures. Grasses grown for pasture are a perennial crop. Nitrogen fertilizer guidelines are based on expected yield. The expected yield will vary with such factors as intended use, management intensity, and soil texture.

Nitrogen Guidelines for grasses and grass mixtures in Minnesota.

Nitrogen Table.bmp

Expected yields of 4 or more tons of dry matter per acre are reasonable for situations where soils have good water holding capacity and intensive management practices such as rotational grazing.

The time for nitrogen fertilizer application should match the growth pattern of forage grasses. The majority of grasses found in Minnesota are cool season grasses. With cool season grasses, the majority of growth takes place in late spring and early summer. Therefore, early spring application is suggested for these grasses.

Split application of nitrogen fertilizer is an option for intensive management situations when expected yields are greater than 4 ton per acre. If split application is an option, 75% of the nitrogen should be applied in early spring and 25% in late August.

The listed rates for rates for phosphate and potash can be taken from the results of your soil test. The needed fertilizer should be broadcast to established pastures in early spring for cool season grasses.

Phosphate fertilizer guidelines for grasses and grass mixtures.

Phosphorus Table.bmp

Potash fertilizer guidelines for grasses and grass mixtures.

Potassium Table.bmp

In some field crops, other nutrients have been found to be of value. Research trials in Minnesota have shown that forage grasses and grass mixtures have not responded to application to other nutrients in a fertilizer program. Therefore, none are suggested.

For more information on fertilizer recommendations in Minnesota consult "Fertilizer Guidelines for Agronomic Crops in Minnesota" BU-06240-S Revised 2011, Daniel E. Kaiser, Extension Soil Scientist; John A. Lamb, Extension Soil Scientist; and Roger Elieason, Director, University of Minnesota Soil Testing Laboratory. For more information, visit online: