Data from: Using spatially rich datasets to assess the influence of channel characteristics on biogeochemical behavior in agricultural watersheds

This dataset represents water quality data collected from ditch and streams in a Minnesota Agricultural Watershed, High Island Creek. Data were collected from an inflatable raft with high spatial resolution resulting in water quality maps for selected portions of the watershed. These data were interpreted within the ecological context of spatial leverage to characterize watershed influences on nitrogen and carbon transport or removal from the stream. These data were used to prepare a manuscript for publication in the journal: Water Resources Research. The abstract and plain language summary from that paper is copied below.AbstractMany agricultural landscapes have undergone significant modifications to drain farmland and improve crop productivity. Subsurface field drainage, ditching and channelization of streams limit opportunities for biogeochemical processing of carbon and nutrients within the channel network. In this study, we used spatially rich water quality data collected from two contrasting regions of an agricultural watershed in south-central Minnesota, USA to assess how watershed features, such as channelization, tile drainage, and presence of lakes or wetlands, influence biogeochemical processing of nitrate (NO3-) and dissolved organic carbon (DOC). In the channelized upstream region, land use is predominantly agricultural (> 92%) with subsurface tile drainage commonly discharging directly to the stream channel. Further downstream, the channel is more natural with increasing lakes and wetlands, including riparian wetlands. We used the concept of reach leverage to interpret biogeochemical behavior (i.e., source vs. sink) in each region of the watershed. Results indicate variability in biogeochemical behavior between the distinct watershed regions, suggesting that channel characteristics and the presence of lentic waters play a role in regulating biogeochemical processing. The upstream, channelized region acts primarily as a conservative transporter or small source of both NO3- and DOC across sampling dates. In contrast, the lentic-influenced region exhibited shifts between source and sink behavior over time, especially for NO3-, influenced by factors such as hydrologic connectivity and discharge. These findings highlight the value of collecting spatially resolved data to enhance our understanding of biogeochemical processing which may be useful to inform effective management and conservation strategies.Plain Language SummaryMany farmlands have been altered to drain water and increase crop production. These changes often involve straightening natural stream channels, which reduces their ability to use nutrients and carbon. In this study, we collected detailed water quality data from two different areas of an agricultural watershed in south-central Minnesota to see how features like straightened channels, drainage systems, and the presence of lakes or wetlands affect the processing of nitrate (NO3-) and dissolved organic carbon (DOC). The upstream area is mostly farmland with drainage systems that empty directly into the stream, while the downstream area has more lakes and wetlands, creating a more natural stream environment. We used a method called reach leverage to understand whether areas of the watershed were sources of NO3- and DOC, or if they removed them. Our results showed differences in nutrient processing between the two areas. The upstream, straightened region mainly transported or slightly increased NO3- and DOC, while the downstream, wetland-rich region alternated between acting as a source and a sink for NO3- depending on water flow and other factors. These findings highlight the importance of collecting detailed, location-specific data to understand nutrient processing and for developing better land and water management strategies.

本数据集展示了从明尼苏达州农业流域中的沟渠和溪流收集的水质数据，具体为高岛溪流域。数据通过使用充气筏以高空间分辨率进行收集，从而生成流域选定区域的水质图。这些数据在生态学背景下，结合空间杠杆作用，用于描述流域对氮和碳在溪流中传输或去除的影响。这些数据被用于撰写一篇准备在《水资源研究》期刊上发表的论文。以下是该论文的摘要和通俗易懂的总结摘要。

摘要：众多农业景观经历了显著的改造，以排干农田并提高作物产量。地下田间排水、沟渠和溪流渠道化限制了碳和营养物质在渠道网络中的生物地球化学转化机会。在本研究中，我们利用了从美国明尼苏达州南中部一个农业流域的两个对比区域收集的丰富空间水质数据，以评估流域特征，如渠道化、地下排水管和湖泊或湿地的存在，如何影响硝酸盐（NO3-）和溶解有机碳（DOC）的生物地球化学转化。在上游渠道化区域，土地利用以农业为主（>92%），地下排水管通常直接排放到溪流渠道中。进一步下游，渠道更加自然，湖泊和湿地（包括河岸湿地）数量增加。我们利用流域范围杠杆的概念来解释流域各区域的生物地球化学行为（即，源与汇）。结果表明，不同流域区域之间生物地球化学行为的差异，表明渠道特征和静水体的存在在调节生物地球化学转化中发挥着作用。上游渠道化区域主要作为保守的传输者或NO3-和DOC的小型来源，在采样日期间保持稳定。相比之下，受静水体影响的区域在源与汇行为之间随时间发生转变，尤其是NO3-，这受到水文连通性和排放等因素的影响。这些发现强调了收集空间解析数据以增强我们对生物地球化学转化的理解的价值，这可能对制定有效的管理和保护策略具有参考价值。

通俗易懂的总结摘要：许多农田已被改造以排水和增加作物产量。这些改造通常涉及直化自然溪流渠道，这减少了它们利用营养物质和碳的能力。在本研究中，我们收集了明尼苏达州南中部一个农业流域两个不同区域的水质数据，以观察直化渠道、排水系统和湖泊或湿地的存在如何影响硝酸盐（NO3-）和溶解有机碳（DOC）的转化。上游区域主要是农田，排水系统直接排入溪流，而下游区域有更多的湖泊和湿地，形成了更加自然的溪流环境。我们使用了一种称为流域范围杠杆的方法来了解流域的哪些区域是NO3-和DOC的来源或去除者。我们的结果显示了两个区域之间营养物质转化的差异。上游直化区域主要传输或轻微增加NO3-和DOC，而下游富含湿地的区域在NO3-作为水源或汇源的行为之间交替，这取决于水流和其他因素。这些发现强调了收集详细、地点特定的数据以了解营养物质转化并制定更好的土地和水管理策略的重要性。