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Penetration resistance of gypsiferous horizons
Author(s) -
POCH R. M.,
VERPLANCKE H.
Publication year - 1997
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/j.1365-2389.1997.tb00219.x
Subject(s) - penetrometer , gypsum , penetration (warfare) , soil water , soil science , geology , penetration test , entisol , water resistance , mineralogy , geotechnical engineering , environmental science , materials science , composite material , mathematics , operations research , subgrade , paleontology
Summary To assess the importance and the possible causes of penetration resistance of horizons with gypsum, 20 horizons in seven irrigated profiles were studied. Gypsum contents ranged from 0 to 900 g kg −1 . Penetrometer tests were performed on undisturbed soil cores by means of a needle penetrometer at different matric potentials. The increase of penetration resistance on drying was caused by changes in the effective stress of the soils, calculated from their soil water characteristic curves. Multiple regression tests showed that besides water content and bulk density, gypsum content was positively correlated with penetration resistance. It seems that in the soils studied the increase of penetration resistance caused by gypsum is due to the growth of gypsum crystals in pre‐existing pores, which reduces the volume of regular and continuous voids necessary for root growth.