Methods matter! To ensure transparency in our lab’s work, facilitate the work of others, and encourage open discussion on measurements of soil processes and properties, we are proud to share our group’s standard operating procedures (SOPs). Many of these methods, in particular soil enzyme assays, are the subject of methodological development by our group; please refer to Publications for peer-reviewed articles that provide rationale and richer discussion on these.
Lab-based SOPs
- Autoclave-extractable (ACE) protein
- Aggregate fractionation (wet sieving)
- Ammonium-N extraction + colorimetry
- CO2 quantification (IRGA) – part of mineralizable C
- Deaminase assay
- Dissolved organic C / total N
- Enzyme assays using pNA-linked substrates (amide bonds)
- Enzyme assays using pNP-linked substrates (ester and glycosidic bonds)
- Additional discussion can be found in this YouTube webinar
- Free amino acids
- Fourier-transform infrared (FTIR) spectroscopy
- Gravimetric water content (GWC); calculation template.
- Mehlich III-extractable P
- Microbial biomass C and N (chloroform gas fumigation)
- Microbial biomass P (hexanol liquid fumigation)
- Microbial biomass P (chloroform gas fumigation)
- Nitrate-N extraction + colorimetry
- Oxidative enzymes (peroxidase, phenol oxidase)
- Permanganate-oxidizable C (POXC)
- Protease assay
- Resin extractable P
- Resin lysimeter – assembly
- Resin lysimeter extraction for leachate N and P determination
- Root washing
- Sequential P fractionation (modified Hedley)
- Sequential inorganic P fractionation (Chang & Jackson)
- Soil pH
- Texture (by hydrometer)
- Total C and N
- Total P (soils, plants) by wet digestion (HNO3+H2O2)
- Total P (soils) by lithium borate fusion
- Total organic P (soils)
- Water-extractable Pi (WEP)
- Water-holding capacity (WHC)
Field-based SOPS
- Corn / soybean aboveground biomass*
- Cover crop aboveground biomass
- Belowground biomass: in-growth root cores
- Belowground biomass: root transect sampling
- Tissue grinding
- Giddings coring and sectioning
- Greenhouse gas (GHG) emissions
- Resin lysimeter installation and harvest
- HOBO temperature sensors