Soil Organic Matter and Phosphorus Chemistry of Acidic Barren Soils: Ultrahigh Resolution FT-ICR Mass Spectrometry and NMR Studies.

The effects of organic and conventional blueberry production on soil phosphorus and organic matter chemistry were investigated with ³¹P-NMR and ultrahigh resolution mass spectrometry, respectively.  In addition, acid phosphatase and b-glucosidase enzymatic activities were measured to investigate processes that regulate soil P bioavailability and C dynamics.  Regression analysis indicated that water-extractable P was preferentially adsorbed to short-range ordered (SRO) Al minerals, while OM was preferentially adsorbed to SRO-Fe minerals.  The ³¹P-NMR results show that organic management soils had lower inorganic to organic ratios of soil P (0.9) as compared to the three conventional management soils (4.6).  Principal component analysis shows that orthophosphate-P and the lignin components of OM were associated with SRO-Al minerals, and that the condensed aromatic OM components and monoester- and DNA-P species were associated with the SRO-Fe minerals.  It is speculated that soil amendments with OM containing greater lignin content may be more effective in increasing soil P bioavailability which may reduce the quantity of P fertilizer used.