<?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%">Otieno, D. O.</style></author><author><style face="normal" font="default" size="100%">Mirzaei, H.</style></author><author><style face="normal" font="default" size="100%">Hussain, M. Z.</style></author><author><style face="normal" font="default" size="100%">Li, Y. L.</style></author><author><style face="normal" font="default" size="100%">Schmidt, M. W. T.</style></author><author><style face="normal" font="default" size="100%">Wartinger, M.</style></author><author><style face="normal" font="default" size="100%">Jung, E.</style></author><author><style face="normal" font="default" size="100%">Ribeiro, N.</style></author><author><style face="normal" font="default" size="100%">Pereira, J. S.</style></author><author><style face="normal" font="default" size="100%">Tenhunen, J.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Herbaceous layer development during spring does not deplete soil nitrogen in the Portuguese montado</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Arid Environments</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Biomass development of the herbaceous vegetation</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean ecosystems</style></keyword><keyword><style  face="normal" font="default" size="100%">pasture</style></keyword><keyword><style  face="normal" font="default" size="100%">Plant and soil nitrogen pools</style></keyword><keyword><style  face="normal" font="default" size="100%">Portuguese montado</style></keyword><keyword><style  face="normal" font="default" size="100%">Root distribution and nutrient uptake</style></keyword><keyword><style  face="normal" font="default" size="100%">Soil moisture</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><urls><web-urls><url><style face="normal" font="default" size="100%">http://linkinghub.elsevier.com/retrieve/pii/S0140196310002922</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">75</style></volume><pages><style face="normal" font="default" size="100%">231 - 238</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Nitrogen (N) content in the soil and in the herbaceous biomass were monitored during spring of 2004e2006 to determine how the herbaceous layer development inﬂuences soil N availability in the montado ecosystem of southern Portugal. Highest (246.6 52.7 g m2 ) and lowest (123.2 89.5 g m2 ) peak biomass occurred in 2006 and 2005 respectively. Total soil N within the top 20 cm soil proﬁle ranged between 0.2 0.1% in February and 0.41 0.2% in May, while available soil N was lowest (5 2 mg g 1 soil) in February but increased three-to-ﬁve fold in March and was &gt;17.5 mg g 1 soil at senescence in May. Signiﬁcant (p &lt; 0.001) increase in total N in the aboveground pool occurred between February and May. There was however, no decay in soil N content. Instead, the herbaceous vegetation enhanced soil N input and N retention in the ecosystem. Most of the herbaceous plants were annuals with large reserves of organic N at senescence, which returned to the soil as detritus. The herbaceous vegetation is a critical component of the montado that contributes to N recharge and cycling within the ecosystem</style></abstract><issue><style face="normal" font="default" size="100%">3</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%">Otieno, D. O.</style></author><author><style face="normal" font="default" size="100%">Kurz-Besson, C.</style></author><author><style face="normal" font="default" size="100%">Liu, J.</style></author><author><style face="normal" font="default" size="100%">Schmidt, M. W. T.</style></author><author><style face="normal" font="default" size="100%">Do, R. Vale-Lobo</style></author><author><style face="normal" font="default" size="100%">David, T. S.</style></author><author><style face="normal" font="default" size="100%">Siegwolf, R.</style></author><author><style face="normal" font="default" size="100%">Pereira, J. S.</style></author><author><style face="normal" font="default" size="100%">Tenhunen, J. D.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Seasonal Variations in Soil and Plant Water Status in a Quercus suber L. Stand: Roots as Determinants of Tree Productivity and Survival in the Mediterranean-type Ecosystem</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%">Drought stress</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf water potential</style></keyword><keyword><style  face="normal" font="default" size="100%">osmotic adjustment</style></keyword><keyword><style  face="normal" font="default" size="100%">oxygen isotope</style></keyword><keyword><style  face="normal" font="default" size="100%">root distribution</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2006</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2006///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.springerlink.com/index/10.1007/s11104-004-7539-0</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">283</style></volume><pages><style face="normal" font="default" size="100%">119 - 135</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Studies were conducted to examine changes in soil (Ys) and plant water status during summer in a 16-year old Quercus suber plantation in southern Portugal. Continuous measurements were conducted between May 2003 and August 2004, while discontinuous measurements were conducted on a monthly basis between May and September 2003 and repeated between March and September 2004. Intensive measurements were conducted on ﬁve trees with mean height and DBH of 5.3 m and 11.6 cm, respectively, growing at close proximity to each other. Weather conditions and soil water potential (Ys) at the rhizosphere of each of the trees measured at 0.3 and 1 m soil depth were continuously monitored. Predawn (Ypd) and midday (Ymd) leaf water potentials were determined every month. Soil and plant samples were also collected in June and September from diﬀerent locations within the study site for d 18 O isotope composition analysis. Pressure–volume (p–v) curves were constructed from plant shoots at diﬀerent times during the vegetative period to determine osmotic potential at full saturation (P 100 ), water potential at turgor loss point (Ytlp), relative water content at turgor loss point (R*tlp) and bulk modulus of elasticity (e). Signiﬁcant P &lt; 0.05 decline in Ys occurred between May and September, the lowest value recorded being –2.0 MPa. Decline in soil moisture aﬀected tree water status, but decline in leaf water potential varied signiﬁcantly (P &lt; 0.05) among the trees. At the end of summer drought, lowest Ypd measured was –1.7 MPa while the highest measured during this time was –0.8 MPa. Diﬀerences among trees were attributed to diﬀerences in rooting depth, as shown by regression analysis of 18 O isotopes. Radial stem growth ceased when Ys within the upper 0.3 m depth approached –1.5 MPa. The upper soil layers contributed approximately 33% of the total tree water requirement, between spring and mid summer when drought was experienced by trees. Deep soil layers however, supplied most of the water required during drought and no growth was recorded during this time. Stressed trees increased solute concentration of their tissues by a Magnitude of 0.7 MPa while bulk tissue elastic modulus increased by about 17 MPa. The study emphasizes the signiﬁcance of roots as determinants of tree productivity and survival in the Mediterranean ecosystems.</style></abstract><issue><style face="normal" font="default" size="100%">1-2</style></issue></record></records></xml>