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

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Mc Laughlin, R. A. Articles by Hansen, E. A. Search for Related Content PubMed Articles by Mc Laughlin, R. A. Articles by Hansen, E. A. Agricola Articles by Mc Laughlin, R. A. Articles by Hansen, E. A.

Nitrogen Fertilization and Ground Cover in a Hybrid Poplar Plantation: Effects on Nitrate Leaching¹

ABSTRACT

A 3-yr study in northern Wisconsin measured the effects of ground cover treatments and N fertilization on tree growth, NO₃^–-N leaching, and N mineralization in an irrigated hybrid poplar (Populus deltoides Bartr. x P. trichocarpa Torr. and Gray, clone NC-9922) plantation. Annually fertilized (112 kg N/ha per year) and unfertilized plots were either maintained weed-free (bare soil), allowed to revegetate with native weeds, or seeded to birdsfoot trefoil (Lotus corniculatus L.). Soil solution NO₃^–-N was monitored in samples from permanently installed cup lysimeters. During the first two growing seasons, fertilization in bare soil plots increased NO₃^–-N concentrations below the rooting zone to over 150 mg N/L. Tree growth response to fertilization in these plots occurred primarily in the third growing season, and NO₃^–-N concentrations were much lower in and below the rooting zone relative to previous years. Fertilization increased NO₃^–-N concentrations in the rooting zone during growing seasons two through four in trefoil plots and three and four in native weed plots. Nitrate-N concentrations below the rooting zone in all trefoil and native weed plots averaged 11 mg/L until the end of the fourth growing season when it averaged 20 to 24 mg/L in fertilized plots. Fertilization significantly increased soil N mineralization in buried plastic bags only in plots with a ground cover and was 42 to 47% greater in these plots compared with fertilized bare soil plots. This study indicates that ground cover plays an important role in preventing leaching losses of fertilizer and native soil N in young biomass plantations.

Key Words: biomass plantations • weed control • Lotus corniculatus L. • Populus spp.

¹ Journal Article no. 9947 of the Purdue Univ. Agric. Exp. Stn. Research supported in part by the USDA Forest Service, North Central Forest Exp. Stn., St. Paul, MN 55108 (Agreement no. NC 13-80-35).

² Graduate instructor and associate professor, Dep. of Forestry and Natural Resourc., Purdue Univ., W. Lafayette, IN 47907; and principal hydrologist, USDA Forest Service, For. Sci. Lab., Rhinelander, WI 54501.

Received for publication July 13, 1984.