Ohno,T. and Amirbahman,A.(2010): Phosphorus availability in boreal forest soils: A geochemical and nutrient uptake modeling approach. Geoderma, 155, 46-54.

『北方林土壌におけるリンの有用性:地球化学的および栄養吸収モデル化によるアプローチ』


Abstract
 Changes in soil surface charge and phosphorus (P) sorption capacity of soils may affect the availability of P in soils. We investigated how changes in soil properties in the Bear Brook Watershed in Maine (BBWM), which is a long-term paired-watershed experimental acidification study, may affect P availability using the Cushman-Barber plant nutrient uptake simulation model. Both NH4Cl- and water-extractive P and Al in mineral soils were significantly related to soil organic matter content. The results from this study suggest that P solubility in the BBWM soils is controlled through the formation of amorphous aluminum phosphate (Al(OH)2H2PO4) with a log ion activity product (IAP) between -28.6 and -28.8. Surface charge titration and batch P adsorption experiments were conducted on mineral soils from BBWM. The surface charge titration curve was fit to a three-site Langmuir model with the Type 1 site having an average OH- binding strength log K1 of 8.7 and 12% of the surface charge, Type 2 site with log K2 of 6.0 and 23% of the surface charge, and the Type 3 site with a log K3 of 4.2 and 65% of the surface charge. The Cushman-Barber simulation model predicted a 15% and 31% increase in P availability in the acid-treated watershed soils for the softwood and hardwood stands, respectively. This was primarily due to increased water-soluble P content in these soils, suggesting that soil acidification leads to increased P availability to plants. The results from this study clearly demonstrate the importance of the Al-P-organic matter interaction in determining the level of soluble P in soils, a key determinant of P bioavailability to plants.』

1. Introduction
2. Materials and methods
 2.1. Site description and soil sampling
 2.2. Soil chemical characterization
 2.3. Surface charge determination and modeling
 2.4. Phosphorus adsorption isotherm
 2.5. Cushman-Barber modeling
3. Results and discussion
 3.1. Soil surface charge
 3.2. Soil phosphorus chemistry
 3.3. Cushman-Barber P uptake modeling
4. Conclusions
Acknowledgments
References


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