Fertilization of Extremely Grazed and Moderately Grazed Mixed-Grass Prairie with Slow Release Phosphorus and Urea

J. M. Volk, W.T. Barker, P. Nyren and D. Whitted

NDSU Animal and Range Sciences Department, and Central Grasslands Research Extension Center
 

• Introduction
• Methods
• Results

• Extremely Grazed Trial

• Moderately Grazed Trial
• Conclusion

Introduction

Many studies have reported on fast release nitrogen and phosphorus fertilization of rangeland, but few have reported on slow release fertilizers or changes in botanical composition as a result of fertilization, which may be as important as changes in forage production. Response of extremely and moderately grazed mixed-grass prairie vegetation to annual applications of slow release phosphorus (P) and slow release urea (N) was studied during a four-year period at the Central Grasslands Research Extension Center (CGREC) near Streeter, North Dakota. Fertilizer rates of 0, 24, and 48 pounds/acre of elemental P were applied May 1 and June 20. Fertilizer rates of 33 and 66 pounds/acre of elemental N were also applied June 20. Both the phosphorus and nitrogen fertilizers are slow release fertilizers encapsulated with a synthetic polymer.
 

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