<?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%">Llorente, Mireia</style></author><author><style face="normal" font="default" size="100%">Glaser, Bruno</style></author><author><style face="normal" font="default" size="100%">Turrión, María-Belén</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Anthropogenic disturbance of natural forest vegetation on calcareous soils alters soil organic matter composition and natural abundance of 13C and 15N in density fractions</style></title><secondary-title><style face="normal" font="default" size="100%">European Journal of Forest Research</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">13C</style></keyword><keyword><style  face="normal" font="default" size="100%">15N</style></keyword><keyword><style  face="normal" font="default" size="100%">density fractions</style></keyword><keyword><style  face="normal" font="default" size="100%">Land use change</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2010</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2010///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.springerlink.com/index/10.1007/s10342-010-0402-3</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">129</style></volume><pages><style face="normal" font="default" size="100%">1143 - 1153</style></pages><isbn><style face="normal" font="default" size="100%">1034201004023</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">In the last century, many calcareous soils in Castilla Leo´n (northwestern Spain) have been transformed from natural Quercus ilex forest to cropped land. Reforestation with Pinus halepensis has been taking place during the past 40 years. In order to obtain a better understanding of how these disturbances affect ecosystem functioning, we studied the quantity and quality of soil organic matter (SOM) in natural forest ecosystems, cropland and Pinus plantations. Density fractionation combined with ultrasonic dispersion enables separation and study of SOM fractions: free organic matter (OM), OM occluded into aggregates and OM stabilized in organo-mineral complexes, considered on the basis of the type of physical protection provided. We separated SOM density fractions and determined the concentrations of C and N, C/N ratios and the natural isotopic abundance (d 13 C and d 15 N values). Transformation of Quercus forest to cropland resulted in major losses of SOC and N, as expected. However, subsequent reforestation with Pinus resulted in good recovery of the original SOC and soil N pools. This indicates the potential for enhanced C storage in agricultural soils by their reversion to a forested state. Study of the density fractions and their 13 C and 15 N signatures enabled better understanding of the high stability of OM in calcareous soils, and analysis of d 13 C variations throughout the proﬁle also enabled identiﬁcation of past C3/C4 vegetation change. Despite the different OC contents of soils under different land use, OM stabilization mechanisms were not signiﬁcantly different. In calcareous soils, accumulation of SOC and N is mainly due to organo-mineral associations, resulting in physicochemical stabilization against further decomposition.</style></abstract><issue><style face="normal" font="default" size="100%">6</style></issue></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%">Llorente, Mireia</style></author><author><style face="normal" font="default" size="100%">Turrión, M Belén</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Microbiological parameters as indicators of soil organic carbon dynamics in relation to different land use management</style></title><secondary-title><style face="normal" font="default" size="100%">European Journal of Forest Research</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Calcareous soil</style></keyword><keyword><style  face="normal" font="default" size="100%">Metabolic quotient</style></keyword><keyword><style  face="normal" font="default" size="100%">Microbial biomass</style></keyword><keyword><style  face="normal" font="default" size="100%">Soil respiration</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year></dates><volume><style face="normal" font="default" size="100%">129</style></volume><pages><style face="normal" font="default" size="100%">73-81</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Labile C fractions: microbial biomass C (MBC), K2SO4 extractable C (CK2SO4 ) and the cumulated mineralized C in 21 days incubation at 28C (C–CO2(21d) ), were compared as land use indicators in a calcareous soil under three different management systems: native Querqus ilex forest (under and outside tree cover), a Pinus halepensis plantation, and cropped land (with cereals). Microbial biomass and activity were found to be low and coincided with high carbonate contents. As indicators of land use, CK2SO4 and C–CO2(21d) showed the same sensitivity as MBC. C–CO2 emissions were measured in an incubation experiment in order to study C mineralization kinetics. The data for cumulative amounts of C–CO2 released showed a good ﬁt (R 2 [0.94) to the ﬁrst-order kinetic model Cm = Co(1 - e -kt ). The kinetic parameters Co and Cok were affected by land use and especially by tree cover. Principal components analysis was applied to the data and the relationship among microbial metabolic quotient (qCO2), labile C pools, and MBC revealed a decrease in efﬁciency of organic substrate utilization with an increase in availability and lability of the organic matter.</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%">Llorente, Mireia</style></author><author><style face="normal" font="default" size="100%">Turrión, M. Belén</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Microbiological parameters as indicators of soil organic carbon dynamics in relation to different land use management</style></title><secondary-title><style face="normal" font="default" size="100%">European Journal of Forest Research</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Calcareous soil</style></keyword><keyword><style  face="normal" font="default" size="100%">Metabolic quotient</style></keyword><keyword><style  face="normal" font="default" size="100%">Microbial biomass</style></keyword><keyword><style  face="normal" font="default" size="100%">Soil respiration</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2009///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.springerlink.com/index/10.1007/s10342-008-0249-z</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">129</style></volume><pages><style face="normal" font="default" size="100%">73 - 81</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Labile C fractions: microbial biomass C (MBC), K2SO4 extractable C (CK2SO4 ) and the cumulated mineralized C in 21 days incubation at 28C (C–CO2(21d) ), were compared as land use indicators in a calcareous soil under three different management systems: native Querqus ilex forest (under and outside tree cover), a Pinus halepensis plantation, and cropped land (with cereals). Microbial biomass and activity were found to be low and coincided with high carbonate contents. As indicators of land use, CK2SO4 and C–CO2(21d) showed the same sensitivity as MBC. C–CO2 emissions were measured in an incubation experiment in order to study C mineralization kinetics. The data for cumulative amounts of C–CO2 released showed a good ﬁt (R 2 [0.94) to the ﬁrst-order kinetic model Cm = Co(1 - e -kt ). The kinetic parameters Co and Cok were affected by land use and especially by tree cover. Principal components analysis was applied to the data and the relationship among microbial metabolic quotient (qCO2), labile C pools, and MBC revealed a decrease in efﬁciency of organic substrate utilization with an increase in availability and lability of the organic matter.</style></abstract><issue><style face="normal" font="default" size="100%">1</style></issue></record></records></xml>