Canadian Forest Service Publications
Nitrogen mineralization assessment using PRSTM probes (ion-exchange membranes) and soil extractions in fertilized and unfertilized pine and spruce soils. 2014. Harrison, D.J.; Maynard, D.G. Canadian Journal of Soil Sciences 94(1):21-34.
Issued by: Pacific Forestry Centre
Catalog ID: 35369
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Several assay approaches that measure mineralizable nitrogen (N) have been used, with varying success, to assess the N supply power of soil. We compared Plant Root Simulators (PRSTM probes, Western Ag Innovations, Inc., Saskatoon, SK) with chemical extractions in an incubation to evaluate how these methods quantify N-mineralization activity of forest soils. Nitrogen mineralization was compared in spruce- and pine-forest soils that had varying N status and had been subjected to 14 yr of N-based fertilization. We paired the assays to determine how the measures co-varied after 1, 2, 4, 6, 8, 10 and 12 wk of incubation. Significant correlations existed between PRS probes and extractable ammonium (NH 4 ) in the spruce (r0.567, PB0.001) and pine (r0.730, PB0.001) soils, although trendlines differed by soil type. Nitrate (NO 3 ) PRS relationships were evident only in the spruce soils (r0.916, PB0.001), as the pine soils produced minimal NO 3 : Both assays provide opportunities for assessing N-mineralization processes in forest soils and differences between assays appear to be related to soil N availability. The PRS probes responded primarily to factors affecting ion mobility because of the cumulative nature of the PRS probes; whereas the static soil extractions were more sensitive to variations in mineralization and immobilization fluxes.