Estimation of reference bulk density from soil particle size distribution and soil organic matter content

Abstract

Crop growth and yield are affected by soil compactness. Rather than using bulk density, it has been suggested that soil compactness be described by relative bulk density, e.g. the degree of compactness, previously defined as the ratio of bulk density (rho) to reference bulk density (rho(ref)). This study investigated relationships between rho(ref) as defined by Hakansson (1990) and soil particle size distribution (PSD) by analysing soil data from 171 experimental sites in Sweden, two in Poland and three in Finland. PSD was characterised either by the common size fractions (i.e. clay, silt and sand content) or by fitting a (continuous) mathematical function to the experimental PSD data. The Rosin-Rammler equation was used for the latter, and the PSID was characterised by the Rosin-Rammler parameters alpha and beta. We present equations for estimation of rho(ref) from either soil textural classes or from alpha and beta in combination with soil organic matter content (OM). It was shown that rho(ref) is largely controlled by OM. The best model (i.e. the model with the smallest value of Akaike Information Criterion) was found to be one that estimates rho(ref) from alpha, beta and OM. The regression models for calculation of rho(ref) presented here could be incorporated into models for calculation of crop yield losses due to soil compaction. Furthermore, we found good agreement between rho(ref) and values for critical bulk density for root growth reported in the literature, indicating that rho(ref) is a critical bulk density for root growth. (C) 2009 Elsevier B.V. All rights reserved.

Keywords

Reference bulk density; Particle size distribution; Soil texture; Organic matter; Particle density; Degree of compactness; Soil compaction

Published in

Geoderma
2010, volume: 154, number: 3-4, pages: 398-406
Publisher: ELSEVIER SCIENCE BV

SLU Authors

• Keller, Thomas

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    
  • Agroscope
  • Swiss College of Agriculture

UKÄ Subject classification

Agricultural Science

Publication identifier

• DOI: https://doi.org/10.1016/j.geoderma.2009.11.013

Permanent link to this page (URI)

https://res.slu.se/id/publ/59822