It is difficult to control few if any of the experimental variables and winter conditions make it miserable for humans and tough on equipment.
Laboratory studies allow more control and a more comfortable working environment.
However, duplicating winter field conditions in a laboratory setting is a real challenge. A laboratory freezing chamber was designed and built to hold four of the 13-cm diameter by 1.2 m long soil columns we used in our field studies. The columns were packed with a Webster clay loam topsoil. A bromide tracer was placed in the soil layer 5 - 15 cm below the soil surface. The freezing chamber with four soil columns in place was wheeled into a walk-in freezer for 48 hours or more.