Land use change converts temperate dryland landscape into a net methane source

Drylands cover approximately 40% of the global land surface and are thought to contribute significantly to the soil methane sink. However, large-scale methane budgets have not fully considered the influence of agricultural land use change in drylands, which often includes irrigation to create land cover types that support hay or grains for livestock production. These land cover types may represent a small proportion of the landscape but could disproportionately contribute to greenhouse gas exchange and are currently omitted in estimates of dryland methane fluxes. We measured greenhouse gas fluxes among big sagebrush, introduced wetlands, and hay meadows in a semi-arid temperate dryland in Wyoming, USA to investigate how these small-scale irrigated land cover types contributed to landscape-scale methane dynamics. Big sagebrush ecosystems dominated the landscape while the introduced wetlands and hay meadows represented 1% and 12%, respectively. Methane uptake was consistent in the big sag..., Raw flux data for methane, carbon dioxide, and other species were measured using a paired Picarro-Licor trace gas analyzer from June – August 2021 (flux data is in ghg_raw.csv, data for statistical analysis in ghg_stats.csv). Net nitrogen mineralization data was collected through ion exchange resins (data is in n_raw.csv). Bulk density, soil texture, pH, and soil carbon and nitrogen were completed on soil samples analyzed at Yale University (data is in soilcn.csv). Carbon and nitrogen were measured on an elemental analyzer. Soil texture was estimated using particle size analysis. pH was measured using a bench top pH meter. Land cover classification was done using the NatureServe database for Sublette County, WY (data used for scaling is in landcover.xlsx and shapefile is in landcover.zip). In 'included' tab on landcover.xlsx, there are two sections of data on the left and right, not one rectangular table of data., , # Land use change converts temperate dryland landscape into a net methane source Raw flux data for methane, carbon dioxide, and other species were measured using a paired Picarro-Licor trace gas analyzer from June – August 2021 (flux data is in `ghg_raw.csv`, data for statistical analysis in `ghg_stats.csv`). Net nitrogen mineralization data was collected through ion exchange resins (data is in `n_raw.csv`). Bulk density, soil texture, pH, and soil carbon and nitrogen were completed on soil samples analyzed at Yale University (data is in `soilcn.csv`). Carbon and nitrogen were measured on an elemental analyzer. Soil texture was estimated using particle size analysis. pH was measured using a bench top pH meter. Land cover classification was done using the NatureServe database for Sublette County, WY (data is in `landcover.xlsx` and in landcover.zip). In 'included' tab on landcover.xlsx, there are two sections of data on the left and right, not one rectangular table of data. ## Descript...,# 土地利用变化将温带旱地景观转变为甲烷净源 干旱旱地（Drylands）约占全球陆地总面积的40%，被认为对土壤甲烷汇（soil methane sink）具有显著贡献。然而，当前大规模甲烷收支核算尚未充分考虑旱地农业土地利用变化的影响——这类变化通常通过灌溉改造形成可生产饲草或谷物以支撑畜牧生产的土地覆被类型。此类土地覆被类型虽仅占景观的小部分，却可能对温室气体交换产生不成比例的影响，且当前旱地甲烷通量的估算中尚未纳入这类区域。 我们在美国怀俄明州的半干旱温带旱地中，针对大果沙棘（big sagebrush）、人工湿地（introduced wetlands）与干草甸（hay meadows）开展了温室气体通量测量，以探究这类小型灌溉土地覆被类型如何影响景观尺度的甲烷动态。研究区域内大果沙棘生态系统占据景观主导地位，人工湿地与干草甸的占比分别为1%和12%。大果沙棘生态系统的甲烷吸收表现一致，…… 2021年6月至8月期间，采用配对式Picarro-Licor痕量气体分析仪测量了甲烷、二氧化碳及其他物种的原始通量数据，相关通量数据存储于ghg_raw.csv，统计分析所用数据存储于ghg_stats.csv。通过离子交换树脂收集了净氮矿化数据，对应数据存储于n_raw.csv。对土壤样品开展了容重、土壤质地、pH值以及土壤碳氮含量的测定，样品分析工作在耶鲁大学完成，相关数据存储于soilcn.csv。其中，碳氮含量采用元素分析仪测定；土壤质地通过粒径分析进行估算；pH值使用台式pH计测定。土地覆被分类基于怀俄明州萨布利特县的NatureServe数据库完成，缩放分析所用数据存储于landcover.xlsx，形状文件存储于landcover.zip。landcover.xlsx的"included"工作表中，数据分为左右两个独立区块，而非单一的矩形表格。 # 土地利用变化将温带旱地景观转变为甲烷净源 2021年6月至8月期间，采用配对式Picarro-Licor痕量气体分析仪测量了甲烷、二氧化碳及其他物种的原始通量数据，相关通量数据存储于ghg_raw.csv，统计分析所用数据存储于ghg_stats.csv。通过离子交换树脂收集了净氮矿化数据，对应数据存储于n_raw.csv。对土壤样品开展了容重、土壤质地、pH值以及土壤碳氮含量的测定，样品分析工作在耶鲁大学完成，相关数据存储于soilcn.csv。其中，碳氮含量采用元素分析仪测定；土壤质地通过粒径分析进行估算；pH值使用台式pH计测定。土地覆被分类基于怀俄明州萨布利特县的NatureServe数据库完成，缩放分析所用数据存储于landcover.xlsx，形状文件存储于landcover.zip。landcover.xlsx的"included"工作表中，数据分为左右两个独立区块，而非单一的矩形表格。