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Visual structure assessment and mechanical soil properties of re‐cultivated soils made up of loess
Author(s) -
Rücknagel J.,
Dumbeck G.,
Harrach T.,
Höhne E.,
Christen O.
Publication year - 2013
Publication title -
soil use and management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.709
H-Index - 81
eISSN - 1475-2743
pISSN - 0266-0032
DOI - 10.1111/sum.12033
Subject(s) - bulk density , compaction , soil water , arable land , macropore , soil structure , soil science , cohesion (chemistry) , soil compaction , loess , aggregate (composite) , sphere packing , environmental science , geotechnical engineering , mineralogy , materials science , geology , chemistry , composite material , ecology , mesoporous material , biochemistry , organic chemistry , geomorphology , biology , agriculture , catalysis
Re‐cultivated soils (previously piled soils used as the final surface cover in renovation of open cast mine sites) are particularly susceptible to compaction, which is why a simple estimate of mechanical strength is necessary for land management. In this study, therefore, precompression stress (−6 kP a matric potential) was determined for a total of 20 soil layers from 9 repeatedly cultivated areas of arable land in North Rhine–Westphalia (Germany), along with the aggregate density/dry bulk density ratio (as a measure of density heterogeneity) and air capacity (as a soil ecological parameter). These results are contrasted with the determination of packing density. Packing density (PD) is an integrated parameter that combines various properties (aggregate size, cohesion of the soil structure, root distribution, biogenic macropores and aggregate arrangement) and is assessed visually in the field. Packing density levels range between 1 (very loose soil) and 5 (very highly compacted). There is a strongly negative relationship between packing density and both the aggregate density/dry bulk density ratio and air capacity. Conversely, mechanical precompression stress increases with packing density. Ranges of the individual parameters can be assigned to each of the packing density levels. Packing density level 3 represents an optimization with regard to mechanical soil stability whilst maintaining minimum air capacity requirements (5–8 Vol.‐%).