An assessment of soil respiration on two contrasting urban forestry areas using the Solvita^TM Gel System

ABSTRACT

Inadequate soil conditions can affect tree health and longevity but there are few tools available to urban foresters to carry out soil assessments. The Solvita^TM Gel System field test, developed for agricultural purposes, assesses biological activity in soil samples by measuring CO₂ respiration rates.  This test was used alongside other analytical tests using soil samples from two contrasting urban sites; a wooded area and a grassed area with semi-mature trees. The wooded site had 156% higher levels of NPK, 240% more soil organic matter and 252% more easily oxidisable soil organic carbon than the grassed site. In addition, the Solvita^TM Digital Colour Reader value and basal respiration was 196% higher for the wooded site. Soil bulk densities were recorded at 0.97 g cm^-3 and 1.45 g cm^-3 for the wooded and grassed sites respectively. There were significant correlations between basal respiration results and soil organic matter content. A calibrating laboratory experiment identified significant differences in Solvita^TM test values between five soil sample groups with increasing leaf mould content. We conclude that the Solvita^TM Gel System field test has the potential to be used as an urban forest soil assessment tool and its use warrants further research.

KEYWORDS:

• Basal respiration
• soil bulk density
• soil organic matter
• Solivta^TM gel system
• urban soil quality

Acknowledgments

We are grateful for the support of Dr Alan Birtle and his training in the use of relevant laboratory facilities.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

Kit Hardy

Kit Hardy is an arboricultural consultant at A.T. Coombes Associates Ltd, Norwich, England. He is a recent graduate of the MSc in Arboriculture & Urban Forestry course delivered by Myerscough College. His primary interests are in urban forest soils, tree health, tree risk management and fungi.

Irene Weir

Dr Irene Weir is a senior lecturer in Horticulture at Myerscough College, delivering plant and soil science modules and with research interests in soil biology.

Duncan Slater

Duncan Slater is a senior lecturer in arboriculture at Myerscough College and a current candidate for a MEd degree at the University of Central Lancashire.