Phosphorus fractions in grassland and shrubland soils at the Sevilleta NWR

This study examined the concentration of organic and inorganic phosphorus in surface soils of a Bouteloua gracilis-Bouteloua eriopoda grassland, and a Larrea tridentata shrubland, in the northern Chihuahuan Desert, New Mexico, USA. In this desert where the grassland vegetation has a uniform spatial distribution and individual shrubs have a patchy spatial distribution across the landscape, vegetation strongly influences the distribution of soil nutrients. Most studies of soil phosphorus fractions in desert soils have focused primarily on inorganic P fractions and have demonstrated the importance of geochemical controls on soil P cycling. This study addressed the question of whether organic phosphorus, determined by the presence of different vegetation types, also contributes to soil P cycling. Within soils of similar age, topography, parent material, and climatic regime, samples were collected under and between vegetation and analyzed for P fractions following a modified sequential fractionation scheme.

本研究针对美国新墨西哥州奇瓦瓦沙漠北部的格兰马草-垂穗草（Bouteloua gracilis-Bouteloua eriopoda）草原与三齿拉瑞阿（Larrea tridentata）灌丛的表层土壤，测定了其中有机磷与无机磷的浓度。该荒漠中，草原植被呈均匀空间分布，而单株灌丛在景观尺度上呈斑块状空间分布，植被对土壤养分分布具有显著调控作用。现有针对荒漠土壤磷组分的研究多聚焦于无机磷组分，且已证实地球化学过程对土壤磷循环的调控作用。本研究旨在探究：不同植被类型主导下的有机磷是否同样参与土壤磷循环。在成土年龄、地形、母质与气候条件均一致的土壤中，研究人员在植被冠层下及植被间采集土壤样品，并采用改良的连续分级分离方案对样品中的磷组分进行分析。