<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="6.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Cheng, Yi</style></author><author><style face="normal" font="default" size="100%">Cai, Zu-cong</style></author><author><style face="normal" font="default" size="100%">Zhang, Jin-bo</style></author><author><style face="normal" font="default" size="100%">Chang, Scott X.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Gross N transformations were little affected by 4 years of simulated N and S depositions in an aspen-white spruce dominated boreal forest in Alberta, Canada</style></title></titles><keywords><keyword><style  face="normal" font="default" size="100%">nitrogen</style></keyword><keyword><style  face="normal" font="default" size="100%">NOx</style></keyword><keyword><style  face="normal" font="default" size="100%">nutrients</style></keyword><keyword><style  face="normal" font="default" size="100%">soil properties</style></keyword><keyword><style  face="normal" font="default" size="100%">sulphur and SO2</style></keyword><keyword><style  face="normal" font="default" size="100%">UofA</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2011</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://hxlib.njnu.edu.cn/nsxr/Text%2F2012-10-16-10-04-47qm0swi45xlf2vr45ksvmzo45_Gross%20N%20transformations%20were%20little%20affected%20by%204%20years%20of%20simulated%20N%20and%20S%20depositions%20in%20an%20aspen-white%20spruce%20dominated%20boreal%20f</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">Forest Ecology and Management </style></publisher><volume><style face="normal" font="default" size="100%">262</style></volume><pages><style face="normal" font="default" size="100%">7 pages </style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The effects of 4 years of simulated nitrogen (N) and sulfur (S) depositions on gross N transformations in a boreal forest soil in the Athabasca oil sands region (AOSR) in Alberta, Canada, were investigated using the 15N pool dilution method. Gross NH4+ transformation rates in the organic layer tended to decline (P &lt; 0.10, marginal statistical significance, same below) in the order of control (CK, i.e., no N or S addition), +N (30 kg N ha−1 yr−1), +S (30 kg S ha−1 yr−1), and +NS treatments, with an opposite trend in the mineral soil. Gross NH4+ immobilization rates were generally higher than gross N mineralization rates across the treatments, suggesting that the studied soil still had potential for microbial immobilization of NH4+, even after 4 years of elevated levels of simulated N and S depositions. For both soil layers, N addition tended to increase (P &lt; 0.10) the gross nitrification and NO3− immobilization rates. In contrast, S addition reduced (P &lt; 0.001) and increased (P &lt; 0.001) gross nitrification as well as tended (P &lt; 0.10) to reduce and increase gross NO3− immobilization rates in the organic and mineral soils, respectively. Gross nitrification and gross NO3− immobilization rates were tightly coupled in both soil layers. The combination of rapid NH4+ cycling, negligible net nitrification rates and the small NO3− pool size after 4 years of elevated N and S depositions observed here suggest that the risk of NO3− leaching would be low in the studied boreal forest soil, consistent with N leaching measurements in other concurrent studies at the site that are reported elsewhere.</style></abstract><custom2><style face="normal" font="default" size="100%">Athabasca Oil Sands Region (AOSR)</style></custom2><custom3><style face="normal" font="default" size="100%">http://www.worldcat.org/oclc/5902444093</style></custom3><custom4><style face="normal" font="default" size="100%">OSEMB</style></custom4></record></records></xml>