科研之友
微信
新浪微博
Facebook
分享链接
摘要
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 NH(4)Cl- and water-extractable 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)(2)H(2)PO(4)) with a log ion activity product (lAP) 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 K(1) of 8.7 and 12% of the surface charge, Type 2 site with log K(2) of 6.0 and 23% of the surface charge, and the Type 3 site with a log K(3) 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.
- 出版日期2010-2-15
