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 Related articles in JEQ Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed 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 (14) Citing Articles via Google Scholar Google Scholar Articles by Sparling, G. Articles by Schipper, L. A. Search for Related Content PubMed PubMed Citation Articles by Sparling, G. Articles by Schipper, L. A. GeoRef GeoRef Citation Agricola Articles by Sparling, G. Articles by Schipper, L. A. Related Collections Carbon Sequestration Ecological Risk Assessment Soil Organic Matter

TECHNICAL REPORTS
Ecological Risk Assessment

Three Approaches to Define Desired Soil Organic Matter Contents

^a Landcare Research, Private Bag 11052, Palmerston North, New Zealand
^b Landcare Research, P.O. Box 69, Lincoln, New Zealand

^* Corresponding author (SparlingG{at}LandcareResearch.co.nz)

Received for publication February 13, 2002. Soil organic C is often suggested as an indicator of soil quality, but desirable targets are rarely specified. We tested three approaches to define maximum and lowest desirable soil C contents for four New Zealand soil orders. Approach 1 used the New Zealand National Soils Database (NSD). The maximum C content was defined as the median value of long-term pastures, and the lower quartile defined the lowest desirable soil C content. Approach 2 used the CENTURY model to predict maximum C contents of long-term pasture. Lowest desirable content was defined by the level that still allowed recovery to 80% of the maximum C content over 25 yr. Approach 3 used an expert panel to define desirable C contents based on production and environmental criteria. Median C contents (0–20 cm) for the Recent, Granular, Melanic, and Allophanic orders were 72, 88, 98, 132 Mg ha^-1, and similar to contents predicted by the CENTURY model (78, 93, 102, and 134 Mg ha^-1, respectively). Lower quartile values (54, 78, 73, and 103 Mg ha^-1, respectively) were similar to the lowest desirable C contents calculated by CENTURY (55, 54, 67, and 104 Mg ha^-1, respectively). Expert opinion was that C contents could be depleted below these values with tolerable effects on production but less so for the environment. The CENTURY model is our preferred approach for setting soil organic C targets, but the model needs calibrating for other soils and land uses. The statistical and expert opinion approaches are less defensible in setting lower limits for desirable C contents.

Abbreviations: NSD, National Soils Database

Related articles in JEQ:

This Issue in Journal of Environmental Quality

JEQ 2003 32: 745-750. [Full Text]  

This article has been cited by other articles:

				G. P. Sparling, D. Wheeler, E.-T. Vesely, and L. A. Schipper What is Soil Organic Matter Worth? J. Environ. Qual., March 1, 2006; 35(2): 548 - 557. [Abstract] [Full Text] [PDF]