Desert Fertilization Experiment: ecosystem response to nutrient enrichment across an urban airshed in the Sonoran desert

Launched in 2006 with support from the National Science Foundation (NSF) and leveraged by the CAP LTER, the Carbon and Nitrogen deposition (CNdep) project sought to answer the fundamental question of whether elemental cycles in urban ecosystems are qualitatively different from those in non-urban ecosystems. Ecosystem scientists, atmospheric chemists, and biogeochemists tested the hypothesis that distinct biogeochemical pathways result from elevated inorganic nitrogen and organic carbon deposition from the atmosphere to the land. To test the hypothesis, scientists examined the responsiveness of Sonoran desert ecosystems to nutrient enrichment by capitalizing on a gradient of atmospheric deposition in and around the greater Phoenix metropolitan area. Fifteen desert study sites were established, with five locations each west and east of the urban core, and in the urban core in desert preserves. In addition to the gradient of atmospheric deposition in and around the urban core, select study plots at each of the fifteen desert locations receive amendments of nitrogen, phosphorus, or nitrogen + phosphorus fertilizer. Measured variables include soil properties, perennial and annual plant growth, and atmospheric deposition of nitrogen. At the close of the initial grant period, the CAP LTER assumed responsibility for the project, renamed the Desert Fertilization Experiment, which provides a remarkable platform to study the long-term effects of nutrient enrichment on ecosystem properties. This data set features an amalgamation of data from the CAP LTER's long-term Desert Fertilization Experiment. The data presented here bring together many aspects of the project, and are featured in several papers, notably Hall et al. 2009 and 2011, and Sponseller et al. 2012. Investigators interested in other and more recent data from the CAP LTER's long-term Desert Fertilization Experiment should search the data repository for 'desert fertilization experiment'. Citations: Hall, S. J., B. Ahmed, P. Ortiz, R. Davies, R. A. Sponseller, and N. B. Grimm. 2009. Urbanization alters soil microbial functioning in the Sonoran Desert. Ecosystems 12:654.671. https://doi.org/10.1007/s10021-009-9249-1 Hall, S. J., R. A. Sponseller, N. B. Grimm, D. Huber, J. P. Kaye, C. Clark, and S. L. Collins. 2011. Ecosystem response to nutrient enrichment across an urban airshed in the Sonoran Desert. Ecological Applications 21:640-660. doi:10.1890/10-0758.1 Sponseller, R. A., S. J. Hall, D. Huber, N. B. Grimm, J. P. Kaye, C. Clark, and S. Collins. 2012. Variation in monsoon precipitation drives spatial and temporal patterns of Larrea tridentata growth in the Sonoran Desert. Functional Ecology, DOI 10.1111/j.1365-2435.2012.01979.x.碳氮沉降（Carbon and Nitrogen deposition, CNdep）项目于2006年启动，由美国国家科学基金会（National Science Foundation, NSF）资助，由CAP LTER依托运行，旨在解答一个核心科学问题：城市生态系统的元素循环是否在本质上有别于非城市生态系统。 生态系统科学家、大气化学家与生物地球化学家针对该假说展开验证：大气向陆地沉降的无机氮与有机碳浓度升高，会形成独特的生物地球化学循环路径。 为验证该假说，研究人员借助大凤凰城都会区及其周边的大气沉降梯度，探究了索诺兰沙漠生态系统对养分富集的响应。研究共设立15个沙漠样地：城市核心区以西、以东各设5个样地，城市核心区内的沙漠保护区内亦设5个样地。 除利用城市核心区及其周边的大气沉降梯度外，研究人员还对15个沙漠样地中的部分样方施加了氮肥、磷肥或氮磷复合肥。实测变量涵盖土壤理化性质、多年生与一年生植物生长状况，以及大气氮沉降通量。 初始资助周期结束后，CAP LTER接管了该项目，并将其更名为“沙漠施肥实验（Desert Fertilization Experiment）”，该平台为研究养分富集对生态系统特性的长期影响提供了绝佳的研究载体。 本数据集整合了CAP LTER长期开展的沙漠施肥实验的相关观测数据。本次发布的数据整合了该项目的多维度观测结果，已被多篇学术论文引用，其中代表性文献包括Hall等人2009年、2011年的研究以及Sponseller等人2012年的研究。 如需获取CAP LTER沙漠施肥实验的其他最新数据，研究人员可在数据仓储中检索关键词“desert fertilization experiment”。 参考文献： Hall, S. J., Ahmed, B., Ortiz, P., Davies, R., Sponseller, R. A. & Grimm, N. B. 2009. 城市化改变索诺兰沙漠的土壤微生物功能. 《生态系统（Ecosystems）》12: 654-671. https://doi.org/10.1007/s10021-009-9249-1 Hall, S. J., Sponseller, R. A., Grimm, N. B., Huber, D., Kaye, J. P., Clark, C. & Collins, S. L. 2011. 索诺兰沙漠城市气区范围内生态系统对养分富集的响应. 《生态应用（Ecological Applications）》21: 640-660. doi:10.1890/10-0758.1 Sponseller, R. A., Hall, S. J., Huber, D., Grimm, N. B., Kaye, J. P., Clark, C. & Collins, S. 2012. 季风降水变化驱动索诺兰沙漠三齿拉瑞阿（Larrea tridentata）生长的时空格局. 《功能生态学（Functional Ecology）》, DOI: 10.1111/j.1365-2435.2012.01979.x.