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 (1) Citing Articles via Google Scholar Google Scholar Articles by Kumar, K. Articles by Russelle, M. P. Search for Related Content PubMed Articles by Kumar, K. Articles by Russelle, M. P. Agricola Articles by Kumar, K. Articles by Russelle, M. P. Related Collections Residue management Nutrient Cycling Nutrient Management Nitrogen Soil Biochemistry

Nitrogen Management

Enhanced Protease Inhibitor Expression in Plant Residues Slows Nitrogen Mineralization

^a Dep. of Soil, Water, & Climate, 1991 Upper Buford Circle, Room 439, Univ. of Minnesota, Saint Paul, MN 55108, USA
^b USDA-ARS Plant Sci. Res. Unit, 1991 Upper Buford Circle, Room 439, Univ. of Minnesota, Saint Paul, MN 55108, USA; K. Kumar, current address: Res. and Dev., Metropolitan Water Reclamation District of Greater Chicago, 6001 West Pershing Rd., Cicero, IL 60804-4112

^* Corresponding author (kuldip.kumar{at}mwrd.org)

Received for publication September 8, 2005. Organic N mineralization by extracellular proteases affects inorganic N availability and loss. Soil N mineralization is slowed by addition of purified protease inhibitors. We hypothesized that elevated concentrations of protease inhibitors in plant residues would reduce soil and plant residue N mineralization. Isogenic controls and transgenic plants of Brassica (Brassica napus L.), Japonicum rice (Oryza sativa L.), and tobacco (Nicotiana tabaccum L.) showing enhanced wound-inducible protease inhibitor production were grown in a greenhouse, and leaves were mechanically wounded 3 d before shoot removal. Transgenic plants and their isogenic controls did not differ in N concentration, C/N ratio, or lignin concentration in shoot residues, but protease inhibitor concentration was 1.5 to 2.3 times greater in the transgenic lines. In laboratory incubations in a loamy sand soil, inorganic N in leachate from transgenic plants was significantly lower than isogenic controls for the first 30 d when the residues remained on the soil surface and were higher at one or more dates thereafter. When residues were mixed with soil, differences were observed only for Brassica. Cumulative N mineralization in static incubations of residues mixed with soil followed the order Brassica > tobacco > rice residues. In general, transgenic residues mineralized between 22 and 27% less N than control plant residues in the first 30 d, but no differences in soil N mineralization were detected. Thus, protease inhibitor concentration of plant residues should be included with measures of total N concentration, C/N ratio, and lignin concentration to improve prediction and potentially management of short-term N mineralization from plant residues.

This article has been cited by other articles:

				J. Nyiraneza and S. Snapp Integrated Management of Inorganic and Organic Nitrogen and Efficiency in Potato Systems Soil Sci. Soc. Am. J., August 9, 2007; 71(5): 1508 - 1515. [Abstract] [Full Text] [PDF]