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Data from: Mitigating nitrogen pollution with under-sown legume-grass cover crop mixtures in winter cereals

    This study was part of a cover crop-based, organic rotational no-till cropping systems experiment conducted from 2015-2017 at Pennsylvania State University’s Russell E. Larson Agricultural Research Center in Rock Springs, PA, USA, employing a corn (*Zea mays* subsp. mays L.), soybean (*Glycine max* (L.) Merr.), spelt (*Triticum spelta* L.) rotation that is typical for feed and forage farmers in the Mid-Atlantic USA. Data include: Nitrate leaching from anion resin bags; Nitrous oxide fluxes from static chambers and isotopomers; Soil inorganic N including ammonium and nitrate; Soil moisture and temperature; Cover crop biomass as well as carbon and nitrogen content and nitrogen isotope ratios; Cash crop yields.

    Isotope-corrected Critical Ratio calculations

      This Microsoft Excel workbook (168.259 Mb) calculates Critical Ratios for triacylglycerols based on manually entered mass spectra, with isotope correction by isotope patterns calculated at www.ChemCalc.org. Average mass spectra across integrated peaks are manually entered according to the instructions in the Supplementary Material to the publication 'The Updated Bottom Up Solution for Mass Spectrometry of Soybean Oil in a Dietary Supplement Gelcap".

      Data from: Soil organic carbon and isotope composition response to topography and erosion in Iowa

        The dataset includes topographic information, soil properties, and 137Cs levels collected from a 15 ha cropland under soybean/maize (C3/C4) rotation in June 2002. The cropland is located in the central-western part of the Walnut Creek watershed, Story County, Iowa. 128 sampling locations were collected and three soil samples were obtained using a 3.2 cm-diameter push probe from the 0 to 30 cm soil layer within a 1 m × 1 m quadrat at each sampling location. Deeper soil samples were collected from 30 to 50 cm layers in locations where sediment deposition was observed. The three samples from each sampling location were mixed and analyzed to determine soil properties, SOC content and its carbon (C) isotope composition (C12 to C13 ratio), and 137Cs levels. For landscape topography of each sampling location, topographic metrics were derived from a digital elevation mode using LiDAR (Light Detection and Ranging) data. These data are useful in investigating the fate of eroded SOC in croplands and its responses to landscape topography.