HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Dell, C. J. Articles by Rice, C. W. Search for Related Content PubMed Articles by Dell, C. J. Articles by Rice, C. W. Agricola Articles by Dell, C. J. Articles by Rice, C. W. Related Collections Fire Nutrient Cycling Nitrogen

Division S-3—Soil Biology & Biochemistry

Short-Term Competition for Ammonium and Nitrate in Tallgrass Prairie

^a USDA-ARS-PSWMRU, University Park, PA 16802
^b Department of Agronomy, 2004 Throckmorton Hall, Kansas State University, Manhattan, KS 66506

^* Corresponding author (curtis.dell{at}ars.usda.gov)

The availability of N limits productivity in tallgrass prairie. Spring burning is common because it results in greater plant productivity despite reducing net N mineralization. To better explain how burning affects inorganic N availability in tallgrass prairie, the partitioning of ¹⁵N among plant and soil pools was measured in June and August 1994. Approximately 2.5 µg N g^–1 soil was injected as either NH₄ or NO₃ to a depth of 15 cm within cores in burned and unburned prairie. Cores were removed from the field 6 d after injection, and ¹⁵N recovery in plant and soil N pools was determined. No more than 14% of the applied ¹⁵N remained in inorganic form 6 d after application. The largest portion of the applied ¹⁵N (35–80%) was recovered in the soil organic nitrogen pool (N_o). Burning significantly increased the immobilization of both NH₄ and NO₃ within N_o, and microbial biomass accounted for 50% of the ¹⁵N recovered in N_o. Accumulation of ¹⁵N in plants accounted for 35% of the applied ¹⁵N with a majority recovered from roots. Burning had little effect on ¹⁵N recovery in plants; however, ¹⁵N accumulations in roots were significantly greater when NO₃ was used. Results indicate that immobilization within soil organic matter (SOM) controls the availability of both NH₄ and NO₃ to plants. Increased immobilization in soils with burning probably results largely from increased microbial N demand resulting from greater litter inputs with wider C to N ratios. Further research is needed to determine if abiotic mechanisms for N immobilization also significantly influence N availability in prairie soils.

Abbreviations: N_i, soil inorganic nitrogen pool • N_o, soil organic nitrogen pool • SOM, soil organic matter

This article has been cited by other articles:

				J. H. Davis, S. M. Griffith, W. R. Horwath, J. J. Steiner, and D. D. Myrold Fate of Nitrogen-15 in a Perennial Ryegrass Seed Field and Herbaceous Riparian Area Soil Sci. Soc. Am. J., April 19, 2006; 70(3): 909 - 919. [Abstract] [Full Text] [PDF]