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Topics : Soil Fertility for Forage Crops : Maintenance


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Nitrogen Management for Grasses

Grasses, unlike legumes, require regular applications of nitrogen for optimum production. The rate and timing of nitrogen application should be based on the expected yield through the season. The general recommendation is 40 pounds of nitrogen per ton of expected yield per acre. The best approach to nitrogen management for grasses is to apply the nitrogen in the spring and after each cutting, based on the expected yield for the next cutting. Applying all of the nitrogen at one time is very inefficient and increases the risk that the nitrogen can be lost before the full needs of the crop are met. An example nitrogen management program for intensively managed grass hay is illustrated in Table 2.

Nearly all the common nitrogen fertilizer sources and manure work well for fertilizing grasses. Anhydrous ammonia is an exception because it must be injected into the soil. Urea, UAN (solution nitrogen), and manure will be most effective if applied immediately before rainfall. One-half inch of rain will incorporate the nitrogen and reduce potential nitrogen volatilization losses from these materials. Rain will also reduce plant burning caused by the fertilizer or manure.