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

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Read, J. J. Articles by McGowen, S. L. PubMed PubMed Citation Articles by Read, J. J. Articles by McGowen, S. L. Agricola Articles by Read, J. J. Articles by McGowen, S. L. Related Collections Forage Management Nitrogen Nutrients Animal Waste Irrigation

Swine Effluent Application Timing and Rate Affect Nitrogen Use Efficiency in Common Bermudagrass

^a USDA–ARS, Genetics and Precision Agriculture Research Unit, P.O. Box 5367, Mississippi State, MS 39762
^b USDA–ARS, U.S. Dairy Forage Research Center, 1925 Linden Dr. West, Madison, WI 53706
^c USDA–Natural Resources Conservation Service, 4900 Oklahoma Ave. Suite 300, Woodward, OK 73801. Journal number J-11205 of the Mississippi Agriculture and Forestry Experiment Station. Mention of a trademark, proprietary product or vendor does not constitute a guarantee or warranty of the product by the USDA and does not imply its approval to the exclusion of other products or vendors that also may be suitable

^* Corresponding author (john.read{at}ars.usda.gov).

Received for publication October 17, 2007. Bermudagrass [Cynodon dactylon (L.) Pers.] hay production is integral to manure management on southeastern swine farms. But swine effluent timing must be synchronized with crop nitrogen (N) demands to decrease the potential for soil N accumulation and nitrate (NO₃) leaching. Field studies were conducted on a Prentiss sandy loam (coarse-loamy, siliceous, semiactive, thermic Glossic Fragiudult) to determine N-use efficiency (NUE) and residual soil NO₃–N. Two rates of 10 and 20 cm yr^{– 1} (260 and 480 kg ha^–1 N, respectively) were applied in four timing treatments: April to September (full season), April to May, June to July, and August to September. Plots were harvested every 7 to 9 wk beginning in June, and soil was sampled in fall after a killing frost and the following spring. Annual uptake of N and P were least in the August to September timing treatment. Doubling the effluent rate increased N uptake 112% in 2000 (from 130 to 276 kg ha^–1) and 53% in 2001 (from 190 to 290 kg ha^–1), suggesting 10-cm did not meet crop N demands. Due to low rainfall and decreased forage yield in 2000, doubling the effluent rate led to increased soil NO₃–N to 30-cm depth in fall 2000 and spring 2001. Averaged across timing treatments, soil NO₃–N at 5-cm depth ranged from 8.5 mg kg^–1 in non-irrigated controls to 39.6 mg kg^–1 with 20-cm effluent. Results indicate low NUE in the order of 30 to 38% for applications in August to September increase the risk to surface and ground water quality from excess N remaining in soil.

Abbreviations: DM, dry matter • NH₄–N, ammonium nitrogen • NO₃–N, nitrate nitrogen • NUE, nitrogen use efficiency