Tests that are typically run on soil samples include:
Salinity/Alkalinity/Toxicity (saturation extract):
SP, pH, EC, SAR, ESP, HCO3, CO3, Ca, Mg, Na, Cl, B, K, SO4-S.
Fertility (nutrient status):
DTPA Extractables: Zn, Mn, Fe, Cu, N, TKN, NH4N, NO3N
Exchangeables: X-K, X-Ca, X-Mg, X-Na
Olsen-P (for soils with pH > 5.0)
Bray-P (for soils with pH < 5.0)
SO4S (CaPO4 extract)
Characteristics:
Cation Exchange Capacity, Organic Matter, Particle Size Analysis (Sand/Silt/Clay), CaCO3, Lime Requirement, Bulk Density, Moisture Retention analysis (1/3, 1, 5, 10 and 15 atm)
Totals:
As, C, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Se, Si, Zn
We request 300 to 500 grams of sample material, air or oven-dried, at 55-60°C, and ground to pass through a 2 mm sieve (100 grams are needed for Particle Size Analysis and a minimum of 300 grams are needed for preparing saturated paste).
Sodium Adsorption Ratio and Exchangeable Sodium Percent are calculations derived from analysis of Ca, Mg and Na.
For N and C by combustion (Carlo-Erba), 1 gram of sample material needs to be finely ground to pass through a 60 mesh sieve.
To determine available N-P-K on California soils, we normally analyze for NO3-N, Olsen-P and Exchangeable K.
K-Sol is reported in ppm.