Modifications to the New Soil Extractant H3A.

A new soil extractant (H³A) with the ability to extract NH₄, NO_3, and P from soil was originally developed and tested against 32 soils, which varied greatly in clay content, organic C, and soil pH. Modifications to the extractant include eliminating EDTA, DTPA, and shaking time has been reduced from 30 min to 10 min. This extractant (H³A) eliminates the need for multiple soil extractants when analyzing for inorganic N (ammonium, nitrate, nitrite) and P (ortho or elemental) as well as separate soil P extractants for acid and calcareous soils. The new extractant also maintains the soil extract pH, on average, within one point five units of the soil pH. The extractant is composed of naturally occurring organic acid root exudates and lithium citrate. The extractant contains no N or P compounds. The modifications were tested on 60 soils collected from the NAPT program and 60 soil samples with manure amendments.