Soil Analytical Tests

OM-LOI.

This method the amount of oxidizable organic matter as determined by the gravimetric weight change associated with high temperature oxidation of soil organic matter in a muffle furnace. Soil organic matter values are used to estimate potential nitrogen mineralization, pesticide management and for crop production management. The method is generally reproducible within ± 20%.

pH (in 1:2 soil:water).

This method determines the pH of soil using a pH meter. It is most accurate for soils with a pH between 4.0 to 9.0. This method provides values of the disassociated H-ions contacting the electrode. The method is generally reproducible within 0.2 pH units.

P.

This is soil composition test by acid digest. This procedure analyzes the concentration of phosphorus by utilizing a nitric acid/hydrogen peroxide closed vessel microwave digestion. Determination is by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). The approximate method detection limit is 1 mg/kg.

SP.

This is a soil properties test that quantifies the soil water content of a saturated soil. At saturation all soil pore space is occupied by water and no free water collects on the surface. Estimates of soil water holding capacity, wilting point and texture can be made from the saturated moisture content. The method is generally reproducible within ± 12%.

Na.

This is a soil salinity test. This method determines the concentration of sodium in a soil saturation paste extract using Atomic Absorption Spectrometry (AAS) or Inductively Coupled Plasma Emission Spectrometry (ICP-AES). The method detection limit for these cations is approximately 0.02 mmolc/L on a solution basis and it is generally reproducible within ± 7%.

NO3-N, Olsen P (Bray-P for pH<6), K, Zn, Mn, Fe, Cu, pH & EC (in 1:2 soil:water), Free Lime, xCa, xMg, xNa, B (hot water), CEC, SO4-S.

This is a fertility and salinity package. It tests for nitrates, phosphorus, potassium, zinc, manganese, iron, copper, pH & EC, free lime, exchangeable calcium, exchangeable magnesium, exchangeable sodium, boron, cation exchange capacity and sulfates.

NO3-N, Olsen P (Bray-P for pH<6), K, Zn, Mn, Fe, Cu, SP, pH, ECe, ESP, Free Lime, sK, sCa, sMg, sNa, B (hot water), SO4-S, Cl.

This is a fertility and salinity package. It tests for nitrates, phosphorus, potassium, zinc, manganese, iron, copper, pH, SP, ESP, free lime, soil potassium, soil calcium, soil magnesium, soil sodium, boron, sulfates and chlorine.

SO4-S.

This is a soil fertility test. This method estimates the amount of sulfate sulfur in the soil by extraction with monocalcium phosphate. This method is only accurate for the time of sampling since sulfur is constantly being mineralized in the soil. The method has a detection limit of approximately 0.5 mg/kg sulfur as sulfate and is generally reproducible within 8%.

Total Zn, Mn, Fe, Cu.

This is a combined soil fertility test for zinc, manganese, iron and copper.

TOC.

This is a soil fertility test. It determines the total amount of organic carbon in a soil sample. This analysis is based on Shimadzu C/N analyzer for solid samples.

Zn.

This is a soil fertility test. It utilizes the DTPA micronutrient extraction method that estimates the amount of available zinc in a soil sample. Analyte concentrations are determined by atomic absorption spectrometry (AAS) or inductively coupled plasma atomic emission spectrometry (ICP-AES). The method has shown to be well correlated to crop response to zinc fertilizers. The method detection limit is approximately 0.1 mg/kg and is generally reproducible to ± 10%.