At Iowa Learning Farms, we have many tools in our tool belt to help us collect data and conduct field research. Funded by the USDA-NRCS National Conservation Innovation Grant (NCIG), one tool we use to collect groundwater samples are groundwater suction lysimeters at research farms throughout the state. Lysimeters have been installed at our cover crop mixture sites on research farms throughout Iowa. These fields that are under different crop treatments – single species cover crop, multi species cover crop, and no cover. The lysimeters reach 24” into the fields of corn or soybean to allow us to sample water from the crop root zone and analyze the differences in nitrate-nitrogen leaching among the three treatments. After the lysimeters are installed, we travel to field sites throughout the year and collect water samples.
Once field research is completed at a site, what goes in must come out. Unseasonably warm weather this fall allowed the Iowa Learning Farms team the chance to dig out 24 lysimeters at McNay Research Farm near Chariton in early November. We started by removing crop residue from around the lysimeter cap. We took the protective cap off, cleaned the cap, and then the fun began.
We used a spade to dig out a deep but targeted area of soil around the lysimeter and then removed loose soil.
We continued to dig down until at least 1/3 to 1/2 of the lysimeter tube was exposed. Digging out that much of the lysimeter allowed us to get a grip on the tube and relieve some suction pressure on the lysimeter from the surrounding soil.
After a few strong pulls with a firm grip, the lysimeter worked free of the soil and came out with a final reverse squat.
We collected all 24 of our lysimeters from McNay Research Farms and delivered them back to our lab on campus.