Field Guide. cropping and pastoral grazing on flat to rolling country.

SOIL INDICATORSSoil porosity under <strong>cropping</strong> Remove a spade slice of soil from the side of the hole created bytaking the 20 cm cube of topsoil, or take a number of clods from thesoil structure <strong>and</strong> consistence test. Examine the sample for soil porosity by comparing against the threephotographs opposite.SOIL POROSITY, <strong>and</strong> particularly macroporosity (the number of largepores), influences the movement of air <strong>and</strong> water in the soil. It isimportant to assess soil porosity as well as aggregate size distribution.Soils with good structure have a high porosity between <strong>and</strong> withinaggregates, but soils with large structural units may not havemacropores <strong>and</strong> coarse micropores within the large clods, <strong>and</strong> thereforemay not be adequately aerated.18 VISUAL SOIL ASSESSMENT: Volume 1