Description:  This program focuses on nitrogen mineralization, or the internal generation of NO₃ and NH₄ wiithin soils, at BBWM. This is considered one of the primary indicators of watershed response to experimental treatments with ammonium sulfate.  Results, after more than 10 years of treatment, have shown higher forest floor N mineralization in both hardwood and softwood stands in the treated watershed (West Bear Brook) compared to the reference watershed (East Bear Brook).  N mineralization in addition to other indicators has been linked to the theory that the West Bear Brook Watershed has moved from Stage 1 to Stage 2 of Nitrogen Saturation.  Continuing this program should provide ongoing information about the duration and characteristics of Stage 2 as well as the transition into Stage 3 (the final stage of N saturation).  In addition, greater focus will be placed on linkages of N mineralization with climate (e.g. soil moisture, temperature, etc.).

General Methodology:  Soil samples are periodically collected from both hardwood and softwood stands of each watershed. These samples are split so that half is placed back in the ground (in situ) and the other half is immediately processed for NO₃-N and NH₄-N extractions.  After approximately 6 weeks, in situ samples are retrieved and processed for NO₃-N and NH₄-N extractions.  This allows us to get a temporal rate of net nitrogen mineralization for each forest stand within each watershed.

Data Summary:

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