SGS-LTER Long Term Nitrogen Concentration in LTNPP Monitoring on the Central Plains Experimental Range, Nunn, Colorado, USA 1987 - 2011, ARS Study Number 6

This data package was produced by researchers working on the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University. Long-term datasets and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive project collection within the Digital Collections of Colorado (http://digitool.library.colostate.edu/R/?func=collections&collection_id=3429). The data table and associated metadata document, which is generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection. Additional information and referenced materials can be found: http://hdl.handle.net/10217/83462.
Aboveground plant nitrogen dynamics monitoring consists of two separate data sets. a) Long-term peak-crop nitrogen concentrations have been sampled since 1983 annually from sites sampled for ANPP estimates across the CPER. Plots are clipped for ANPP in August each year and include moderately grazed sites in sections 24 and 25, ungrazed treatments at ESA and owl creek, coarse textured soils in owl creek, fine textured soils in section 25, as well as three catena topopositions in section 24. These datasets have been designed for monitoring and so it is advised to consider calcuating average based at the transect level. B) Seasonal dynamics of life-form (dominant grass, forb, shrub species) nitrogen concentrations were obtained from random grab samples of aboveground plant tissue are taken monthly from May-Aug. and in Oct., Dec., Feb., and April from 1983 – 2007 at sites where ANPP has been collected since 1983 (ESA, ridge, mid-slope and swale in section 24). The objectives are to assess annual/seasonal weather and site productivity/management with quantity and quality of forage and/or litter production. Combined, these two data sets also provide an estimate of nitrogen yield. These data can be linked with secondary producer data sets such as annual cattle weight gains, grasshopper abundance, small mammal monitoring, etc., to assess how forage/plant tissue quantity and quality drive population dynamics. Resources in this dataset:Resource Title: Website Pointer to html file. File Name: Web Page, url: https://portal.edirepository.org/nis/mapbrowse?scope=knb-lter-sgs&identifier=143 Webpage with information and links to data files for download

本数据包由致力于短草草原长期生态研究项目（SGS-LTER）的研究人员所制作，该项目由科罗拉多州立大学负责管理。关于SGS-LTER项目的长期数据集及其背景信息（如提案、报告、照片等）均收录于科罗拉多州数字收藏馆的全面项目集合中（http://digitool.library.colostate.edu/R/?func=collections&collection_id=3429）。生态元数据语言生成的数据表及其相关元数据文档可能通过服务于生态研究社区的其它数据存储库获得，并代表SGS-LTER项目集合的组成部分。更多信息和参考资料可查阅：http://hdl.handle.net/10217/83462。
地上植物氮素动态监测数据集包含两个独立的部分：
a) 自1983年起，对CPER区域内用于估算ANPP的采样点进行年度采样，以监测长期峰值作物氮浓度。每年8月，对用于ANPP的样地进行剪辑，包括第24和第25节的适度放牧地、ESA和猫头鹰溪的未放牧处理区、猫头鹰溪的粗质地土壤、第25节的细质地土壤，以及第24节的三条坡向地貌。这些数据集旨在进行监测，因此建议在样带水平上计算平均值。
b) 从1983年至2007年，每月从5月至8月以及10月、12月、2月和4月，从1983年起收集ANPP的地点（ESA、脊部、中坡和第24节的凹地）随机采集地上植物组织的随机抓取样本，以获取生命形态（优势草类、杂草、灌木物种）的氮浓度季节动态。这些数据的目的是评估年度/季节性天气以及场地生产力/管理对牧草和/或凋落物生产数量和质量的影響。综合这两个数据集，还可以提供氮产量的估计。这些数据可与年度牲畜体重增长、蝗虫丰度、小型哺乳动物监测等次级生产者数据集相结合，以评估牧草/植物组织数量和质量如何驱动种群动态。
数据集中包含的资源：资源标题：指向HTML文件的网站指针。文件名：网页，URL：https://portal.edirepository.org/nis/mapbrowse?scope=knb-lter-sgs&identifier=143 网页包含有关数据和下载链接的信息。