Die invloed van verdigtingspoging, klei-en waterinhoud op verdigting van geselekteerde Hoëveldgronde

Abstract

Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/tjps20 Die invloed van verdigtingspoging, klei-en waterinhoud op verdigting van geselekteerde Hoëveldgronde

Advances in soil physics and soil water management research in South Africa, 1979–2003

“…To describe the compactibility and degree of compaction of soils, the maximum and preferably also the minimum bulk densities are required. Strong and similar relationships between maximum bulk density and the clay or silt plus clay content were found by Henning et al (1986), Smith et al (1997a) and Nhantumbo (1998). A method for determining the minimum bulk density of soils was developed by Nhantumbo & Bennie (2001).…”

“…A number of pedotransfer functions were developed or applied, relating soil textural parameters to water retentivity (Hutson, 1986;Mottram et at., 1981;Lambooy, 1984;Streuderst, 1985;Van Rensburg, 1988;Bennie & Van Rensburg, 1992;Van Antwerpen et at., 1994), soil compactibility or compressibility (Moolman, 1981;Henning et at., 1986; Huyssteen & Moolman, 1988;Smith et at., 1997;Nhantumbo, 1998) and plant available water (Beukes, 1985;Boedt & Laker, 1985;Bennie et at., 1997).…”

“…During the period under review excellent progress was made with investigating the compactibility and compressibility of South African soils with contributions from Moolman (1981), Henning et al (1986), Van Huyssteen & Moolman (1988), Smith et al (1997aSmith et al ( , 1997b and Nhantumbo (1998). To describe the compactibility and degree of compaction of soils, the maximum and preferably also the minimum bulk densities are required.…”

Quantifying the Impact of Off-Road Driving on Root-Area Distribution in Soils

“…At Site 2 the topsoil (2T) was very close to moderately sorted and the subsoil moderately well. Henning et al (1986) found that soils with moderately sorted sand fractions are more prone to soil compaction than soils with poorly sorted sand fractions. Moolman & Weber (1978) found extreme compaction of well-sorted fine sandy soils in the southwestern Cape of South Africa.…”

“…This negative impact was even during dry soil conditions. It is well known and literature shows that soils with higher water contents (especially those at just below field capacity) are much more susceptible to soil crusting and sub-soil compaction than soils with lower water contents (SASTA, 2001;Bennie, 1972;Henning et al, 1986;Nortjé et al, 2012). Therefore it would be expected that if the root density study was done under wet conditions (higher soil water content), the impact on root density distribution would have been much worse.…”