GLBRC132:Switchgrass Nitrogen Rate Experiment
This dataset contains data from the Switchgrass Nitrogen Rate Experiment (formerly Nitrogen/Harvest) at the KBS GLBRC Intensive Field Site. Switchgrass is grown under 8 rates of nitrogen fertilization (F1-F8; 0-196 kg N/ha) with each treatment plot replicated in four blocks (R1-R4). From 2010–2012, the experiment also included split plots with two harvest strategies (H1, H2; 1 vs 2 harvests/yr) for each nitrogen treatment; from 2013 onward all split plots are harvested only once in the fall, with yields measured separately 2013-2022 and combined starting in 2023.
- Status: active
- Temporal Coverage 2009-01-01 to 2025-12-31
Tables
- GLBRC081-003 Dry Matter Yields
Dry matter yields from machine harvests (~6 inch cutting height) of the Switchgrass Nitrogen Rate Experiment recorded as Mg dry matter per hectare.
- GLBRC088-011 Soil Inorganic Nitrogen
Soil extractable nitrogen (ammonium and nitrate plus nitrate) concentrations in surface soils (0-25 cm) of the Switchgrass Nitrogen Rate Experiment, monitored over the 2009-2010 growing seasons, and reported as mg N per kg dry soil.
- GLBRC088-023 Soil pH
Soil pH of surface cores (0-25 cm) from the Switchgrass Nitrogen Rate Experiment taken periodically to evaluate the need for liming. Analytical samples are prepared from field moist soil samples, sometimes in duplicate resulting in two pH measurements per sample.
- GLBRC088-027 Soil Water Chemistry
Soil water (leachate) samples collected biweekly throughout the growing season from low-tension soil water samplers (also called suction lysimeters) buried ~1.2 meters deep in replicates R2-R4 of the Switchgrass Nitrogen Rate Experiment and analyzed for a range of chemical parameters.
data collection ceased after the 2021 season
- GLBRC091-002 Plant Total Carbon and Nitrogen
Total carbon and nitrogen content in the switchgrass crop of the Switchgrass Nitrogen Rate Experiment. A subsample of the machine harvested crop is dried, ground, and analyzed for carbon and nitrogen content, reported as a percentage; the remaining subsample is archived.
- GLBRC093-006 Soil Bulk Density of Deep Cores
Soil bulk density of deep (0-1 m) cores collected from the Switchgrass Nitrogen Rate Experiment in 2013 for Leilei Ruan. Cores were taken from each treatment plot and sectioned into 0-10, 10-25, 25-50, and 50-100 depth intervals.
- GLBRC096-003 Archived Plant Samples
A list of archived plant material from the Switchgrass Nitrogen Rate Experiment. A subsample from the machine harvested crop is dried, ground and archived, and may also be analyzed for total carbon and nitrogen. Note that “Unsorted” indicates that subsamples from harvested switchgrass are not sorted to species and may contain plant material from other species. Also note that the plot label is derived from the following information “treatment name, plot number – original number of harvests per year”. For “SWF1 108-H1”, as an example, SWF1 is fertilization level #1 (0 kg N/ha), 108 is the plot in block #1 that is the eighth from the west, and H1 is the initial harvest strategy of 1 harvest per year.
- GLBRC130-005 Root Biomass in Deep Cores
Root biomass in deep cores (0-1 m) collected from the Switchgrass Nitrogen Rate Experiment in 2013 for Leilei Ruan. Cores were taken from each treatment plot and sectioned into 0-10, 10-25, 25-50, and 50-100 depth intervals.
- GLBRC132_002 Switchgrass Stand Counts
Stand counts of switchgrass populations in the Switchgrass Nitrogen Rate Experiment periodically conducted in the spring to assess growth and recruitment. Counts are reported in number of plants per square meter.
- GLBRC132-003 Soil Total Carbon and Nitrogen
- Soil total carbon and nitrogen in surface (0-25 cm) and deep (0-1 m) core samples from the Switchgrass Nitrogen Rate Experiment. Deep core samples were collected - in 2013 for Leilei Ruan, taken from each treatment plot, and sectioned into 0-10, 10-25, 25-50, and 50-100 depth intervals. - in 2024 for Ashim. Taken from each plot and sectioned into the same depth intervals.
- GLBRC132-004 Plant N and P from Jach-Smith and Jackson (2020)
Plant nitrogen and phosphorus responses to zero, medium and high nitroen application rates.
- GLBRC132-005 Stable isotope and hyphal biomass data from Jach-Smith and Jackson (2020)
Stable isotope and AMF hyphal biomass responses to zero, medium and high nitrogen application rates.
- GLBRC132-006 Soil nitrogen and phosphorus data from Jach-Smith and Jackson (2020)
Soil nitrogen and phosphorus responses to zero, medium and high nitrogen application rates.
- GLBRC132-007 Decadal deep core CN comparison
- Deep core samples were taken from every plot in 2013 and 2024. This datatable is a complication of the deep core CN data from https://data.sustainability.glbrc.org/datatables/723 and https://data.sustainability.glbrc.org/datatables/734
- GLBRC132-008 Canopy species and height
- Canopy species composition and height is surveyed at or near maturity of the dominant plant species using the Line-Point Intercept (LPI) . This method is used to quantify changes in dominant plant species by measuring their canopy cover and height. It involves lowering a pin or rod at regular intervals along transects and recording the first plant species intercepted. Percent cover for each species is calculated from the number of hits divided by total sampling points, allowing researchers to track shifts in dominance over time
- KBS078-021 Agronomic Soil Chemistry
Agronomic soil test results of the Switchgrass Nitrogen Rate Experiment. Surface soils (0-25 cm) are periodically sampled, air dried, and sent to an analytical laboratory (MSU Soil and Plant Nutrient Lab through 2022) for testing and fertilizer and liming recommendations.