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Title: DEVELOPMENT OF A NEW SOIL EXTRACTANT FOR SIMULTANEOUS PHOSPHORUS, AMMONIUM, AND NITRATE ANALYSIS

Author
item Haney, Richard
item HANEY, E - STATE OF TX-RR COMMISSION
item HOSSNER, L - TEXAS A&M UNIV
item Arnold, Jeffrey

Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/19/2005
Publication Date: 7/15/2006
Citation: Haney, R.L., Haney, E.B., Hossner, L.R., Arnold, J.G. 2006. Development of a new soil extractant for simultaneous phosphorus, ammonium, and nitrate analysis. Communications in Soil Science and Plant Analysis. 37(11-12):1511-1523.

Interpretive Summary: A new soil extractant (H3**A) with the ability to extract NH4, NO3, and P from soil was developed and tested against 32 soils, which varied greatly in clay content, organic C, and soil pH. The extractant (H**3A) eliminates the need for separate P extractants for acid and calcareous soils and maintains the extract pH, on average, within one unit of the soil pH. This new soil extractant will save time and money for soil testing laboratories and possibly improve the accuracy of soil tests.

Technical Abstract: A new soil extractant (H3**A) with the ability to extract NH4, NO3, and P from soil was developed and tested against 32 soils, which varied greatly in clay content, organic C, and soil pH. The extractant (H3**A) eliminates the need for separate P extractants for acid and calcareous soils and maintains the extract pH, on average, within one unit of the soil pH. The extractant is composed of organic root exudates, lithium citrate and two synthetic chelators (DTPA, EDTA). The new soil extractant was tested against Mehlich 3, Olsen and water for extractable P, and 1 M KCl and water extractable NH4 and NO2/NO3. The pH of the extractant after adding soil, shaking, and filtration was measured for each soil sample (5 extractants x 2 reps x 32 soils=320 samples) and was shown to be highly influential on extractable P, but have no effect on extractable NH4 or NO2/NO3. H3**A was highly correlated with soil extractable inorganic N (NH4, NO2/NO3) from both water (r=0.98) and 1 M KCl (r=0.97), as well as being significantly correlated with water (r=0.71), Mehlich 3 (r=0.83) and Olsen (r=0.84) for extractable P.