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Coarse fragmentsCoarse fragments are estimated using the conventions in NCST (2009). The main purpose for the variable isto allow calculation of available water capacity. In <strong>ASRIS</strong>, hard segregations are included in the estimate ofcoarse fragments. Soft segregations are considered part of the fine earth fraction. If porous segregations(i.e. capable of storing water or providing surfaces for ion-exchange) are present, then the porosity ofcoarse fragments needs to be estimated. In most regions, porosity of coarse fragments will be 0.00 m 3 /m 3(see page 47). Use Table 24 for the estimation method.Abundance is estimated as an average percentage for each of the five layers (if source data rely on theclasses listed by NCST (2009, p140), then use midpoints of each class). The control sections for coarsefragments are the same as those for texture.Table 24: Estimation method for coarse fragmentsEstimationMethodDescription1 Estimate based on replicated measurements of coarse fragments in anexposure or soil pits within the land-unit tract2 Estimate based on a single measurement of coarse fragments in the land-unittract3 Estimate based on direct measurements of similar soils in the same land unittype (e.g. modal profiles)4 Estimate based on direct measurements of similar soils in the region orproject area5 Estimate based on experience with similar soils41
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