Soil water chemistry

Aims
  • give data on nutrient conditions and possible toxicity in the soil of relevance to plant roots, fungi, soil fauna and microbes
  • give data on the transport of nutrients, acidifying substances and metals in relation to the water flow
  • establish mass balances of pollutants and other substances in the soil fluid

The soil water is intimately coupled to the chemical and biological processes in the upper soil layers and a sensitive indicator of both acidification and eutrofication. It is essential to follow its composition in order to understand the interplay between soil hydrology and the biological processes on both plot and catchment level.

Soil water is sucked by ceramic bodies in so-called vacuum lysimeters. They are placed in the bleached E layer just below the humus layer and in the B horizon. Three to six ceramic tension lysimeters at each soil depth are installed at one or two places in the catchment. It is difficult to extract available soil water in an indisputable way, but whatever you get adds important information on the situation. Soil water is collected every second month during the frost-free part of the year – if available.

 

Variables

  • normal year: pH, conductivity, Na, K, Ca, Mg, Al, Mn, Fe, NH4, NO3, SO4, Cl, HCO3, total N and total C
  • campaign year additionally: Cu, Zn, Pb, Cd, Hg and labile Al
:
A vaccuum vessel and a tube. Lysimeters used for sucking soil water through porous ceramic "fingers" are installed at two depths in the soil.
The vacuum vessel is partly evacuated and the lysimeter in the soil allowed to suck water for a while. During dry periods no water is taken in.


Contact person: Lage.Bringmark@ma.slu.se