<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Gómez-Rey, Maria Xesús</style></author><author><style face="normal" font="default" size="100%">Madeira, Manuel</style></author><author><style face="normal" font="default" size="100%">Gonzalez-Prieto, Serafin Jesús</style></author><author><style face="normal" font="default" size="100%">Coutinho, João</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Soil C and N dynamics in a Mediterranean oak woodland with shrub encroachment</style></title><secondary-title><style face="normal" font="default" size="100%">Plant and Soil</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">15 N isotope dilution technique</style></keyword><keyword><style  face="normal" font="default" size="100%">gross N mineralization</style></keyword><keyword><style  face="normal" font="default" size="100%">hot water-soluble C</style></keyword><keyword><style  face="normal" font="default" size="100%">particulate organic matter</style></keyword><keyword><style  face="normal" font="default" size="100%">Soil respiration</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2013</style></year></dates><volume><style face="normal" font="default" size="100%">371</style></volume><pages><style face="normal" font="default" size="100%">339-354</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Background and aims Intensive land use has led to degradation and abandonment of Portuguese oak woodlands, and subsequent shrub encroachment may have altered the spatial heterogeneity of soil C and N pools. The aim of this study was to evaluate the effects of shrub invasion on soil C and N dynamics in an oak woodland in Southern Portugal. Methods Soil was sampled beneath and outside scat- tered Quercus suber L. canopies, considering non- encroached areas and areas encroached by shrubs (Cistus ladanifer L. or Cistus salviifolius L.). Results The spatial heterogeneity of soil C and N contents was mainly associated with tree presence. Outside tree canopies, the labile C pools were larger (mainly beneath C. ladanifer) and C cycling was faster in encroached areas than in non-encroached areas. Net and gross N mineralization and urease and protease activities were also higher in encroached than in non- encroached areas; however, the metabolic quotient and the Cmicrobial/Corganic ratio were not significantly affected. Beneath the tree canopy, significant effects of encroachment included a small increase in soil labile C and the enzymatic activity beneath C. ladanifer. Conclusions The results indicate the potential capaci- ty of shrub encroachment to accumulate soil organic C in the long term. The rate of soil C and N turnover promoted by shrub encroachment may depend on the Cistus species present.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Gómez-Rey, Maria Xesús</style></author><author><style face="normal" font="default" size="100%">Garcês, Ana</style></author><author><style face="normal" font="default" size="100%">Madeira, Manuel</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Organic C distribution and N mineralization in soil of oak woodlands with improved pastures</style></title><secondary-title><style face="normal" font="default" size="100%">Revista de Ciências Agrárias</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">agroforestry systems</style></keyword><keyword><style  face="normal" font="default" size="100%">legumes</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean climate</style></keyword><keyword><style  face="normal" font="default" size="100%">soil quality.</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2011</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2011///</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">34</style></volume><pages><style face="normal" font="default" size="100%">80 - 92</style></pages><isbn><style face="normal" font="default" size="100%">0871-018X UL - http://www.scielo.gpeari.mctes.pt/scielo.php?script=sci_arttext&amp;pid=S0871-018X2011000100008&amp;nrm=iso</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Cork oak woodlands in Portugal are a multipurpose agroforestry system occurring in areas mostly degraded by former cereal crops and overgrazing. The objective of this study was to evaluate the effect of scattered cork oak trees (Quercus suber L.) on soil quality, considering two land use systems: unmanaged pastures and improved pastures. Soil samples were collected in a square grid around scattered cork oak trees to evaluate the spatial variability of soil bulk density and chemical properties. In soil samples taken beneath tree canopy and in the open, net N mineralization was evaluated by aerobic incubations. Also, laboratory incubations were carried out to evaluate the effect of roots (tree or/and herbaceous) and water solutions (bulk precipitation, throughfall or stemflow) on net N mineralization.Contents of organic C, total N and extractable P were increased beneath the tree canopy, and gradually decreased with the increase of distance to the tree trunk. Improved pastures established 26 years ago increased organic C (0.76 kg m-2), total N (0.06 kg m-2) and extractable P (2.70 g m-2) amounts in the 0-10 cm soil layer beneath the tree canopy relatively to those of unmanaged pastures. Net N mineralization was significantly greater (about 2 times) in soils beneath the tree canopy than in those of open areas. N mineralization was unaffected by addition of throughfall or stemflow, while a significant reduction resulted from tree roots addition, this effect being stronger for herbaceous plant roots than for tree roots. Maintenance of tree cover combined with permanent improved pastures should be considered to improve soil quality in oak woodlands of Southern Portugal.</style></abstract><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;publisher: scielopt</style></notes></record></records></xml>