Effect of microbial activity on penetrometer resistance and elastic modulus of soil at different temperatures

A - Papers appearing in refereed journals

Gao, W., Muñoz-Romero, V., Ren, T., Ashton, R. W., Morin, M., Clark, I. M., Powlson, D. S. and Whalley, W. R. 2017. Effect of microbial activity on penetrometer resistance and elastic modulus of soil at different temperatures. European Journal of Soil Science. 68 (4), pp. 412-419.

AuthorsGao, W., Muñoz-Romero, V., Ren, T., Ashton, R. W., Morin, M., Clark, I. M., Powlson, D. S. and Whalley, W. R.
Abstract

We explore the effect of microbial activity stimulated by root exudates on the penetrometer resistance of soil and its elastic modulus. This is important because it is a measure of the mechanical strength of soil and it correlates closely with the rate of elongation of roots. A sandy soil was incubated with a synthetic root exudate at different temperatures, for different lengths of time and with selective suppression of either fungi or bacteria. The shape of the temperature response of penetrometer resistance in soil incubated with synthetic exudate was typical of a poikilothermic temperature response. Both penetrometer resistance and small strain shear modulus had maximum values between 25 and 30°C. At temperatures of 20°C and less, there was little effect of incubation with synthetic root exudate on the small strain shear modulus, although penetrometer resistance did increase with temperature over this range (4–20°C). This suggests that in this temperature range the increase in penetrometer resistance was related to a greater resistance to plastic deformation. At higher temperatures (> 25°C) penetrometer resistance decreased. Analysis of the DNA sequence data showed that at 25°C the number of Streptomyces (Gram‐positive bacteria) increased, but selective suppression of either fungi or bacteria suggested that fungi have the greater role with respect to penetrometer resistance.

Year of Publication2017
JournalEuropean Journal of Soil Science
Journal citation68 (4), pp. 412-419
Digital Object Identifier (DOI)doi:10.1111/ejss.12440
Open accessPublished as ‘gold’ (paid) open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeWheat
Delivering Sustainable Systems (SS) [ISPG]
Publisher's version
Output statusPublished
Publication dates
Online22 Jun 2017
Publication process dates
Accepted04 Apr 2017
PublisherBlackwell Publishing Oxford
Wiley
Copyright licenseCC BY
Grant IDS5352
ISSN1351-0754

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