Keller, Thomas
- Institutionen för mark och miljö, Sveriges lantbruksuniversitet
- Agroscope
Sammanfattning
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.
Nyckelord
aggregate stability; dispersible clay; potassium; soil pore size; water retention
Publicerad i
International Agrophysics
2018, volym: 32, nummer: 1, sidor: 57-67
Utgivare: DE GRUYTER OPEN LTD
SLU författare
Globala målen (SDG)
SDG15 Ekosystem och biologisk mångfald
UKÄ forskningsämne
Markvetenskap
Publikationens identifierare
- DOI: https://doi.org/10.1515/intag-2016-0091
Permanent länk till denna sida (URI)
https://res.slu.se/id/publ/93988