Wattle & Daub: Craft, Conservation & Wiltshire Case Study
3.6 Daub
4.1 Soils
4.1.3 Strength
4.2 Dung
4.2.2 Lignin
4.2.3 Urine
4.3 Fibre
5.4.2 Renewal

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4.2.4 Microbial Debris

The microbial debris makes up the majority of the faeces. It has been established that such organic matter helps bind soil aggregates, yet an organic soil also has the undesirable property of being volumetrically unstable and so may shrink in a manner similar to clay.[70] It is possible that the faecal microbial debris in daub is prevented from decomposition by becoming biochemically-protected (chemical compounds that are not subject to decomposition), silt- and clay-protected, or microaggregate-protected (physically protected), although the function of the latter is known to predominate. However, a soil may become saturated with organic material due to limits of these protection mechanisms. Therefore, if too much dung is added to a soil it is likely that a proportion of the organic matter will be unprotected and may then decompose and damage the daub.[71] Protection mechanisms therefore assist a soil to stabilise added microbial debris (i.e. to nullify the affects of organic matter) but do not represent a benefit in their addition to a daub.

[70] New Zealand Ministry of Agriculture and Forestry (2004).
[71] Six, Conant, Paul and Paustian (2002).