Abstract

This study investigated the impact of monovalent cations on clay dispersion, aggregate stability, soil pore size distribution, and saturated hydraulic conductivity on agricultural soil in Iran. The soil was incubated with treatment solutions containing different concentrations (0-54.4 mmol l(-1)) of potassium and sodium cations. The treatment solutions included two levels of electrical conductivity (EC= 3 or 6 dS m(-1)) and six K: Na ratios per electrical conductivity level. At both electrical conductivity levels, spontaneously dispersible clay increased with increasing K concentration, and with increasing K: Na ratio. A negative linear relationship between percentage of water-stable aggregates and spontaneously dispersible clay was observed. Clay dispersion generally reduced the mean pore size, presumably due to clogging of pores, resulting in increased water retention. At both electrical conductivity levels, hydraulic conductivity increased with increasing exchangeable potassium percentage at low exchangeable potassium percentage values, but decreased with further increases in exchangeable potassium percentage at higher exchangeable potassium percentage. This is in agreement with earlier studies, but seems in conflict with our data showing increasing spontaneously dispersible clay with increasing exchangeable potassium percentage. Our findings show that clay dispersion increased with increasing K concentration and increasing K: Na ratio, demonstrating that K can have negative impacts on soil structure.

Keywords

aggregate stability; dispersible clay; potassium; soil pore size; water retention

Published in

International Agrophysics
2018, Volume: 32, number: 1, pages: 57-67
Publisher: DE GRUYTER OPEN LTD

SLU Authors

• Keller, Thomas

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    
  • Agroscope

Sustainable Development Goals

SDG15 Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss


UKÄ Subject classification

Soil Science


Publication identifier

DOI: https://doi.org/10.1515/intag-2016-0091

Permanent link to this page (URI)

https://res.slu.se/id/publ/93988