Agronomic Soil Chemistry — Resource Gradient Experiment
Data in the KBS LTER core database may not be published without written permission of the lead investigator or project director Full terms of use
Agronomic chemistry of surface (0-25 cm) soils occasionally collected in the fall (usually after harvest) for fertilizer and liming recommendations and analyzed for pH, lime index, phosphorus, potassium, calcium, magnesium, and cation exchange capacity by an analytical service laboratory.
This datatable is part of the Resource Gradient Experiment dataset. This dataset contains the agronomic yields and soil properties of the
LTER Resource Gradient Experiment, which applies nine different rates of nitrogen fertilization (F1-F9) to annual row crops under rainfed (since 1999) and irrigated (since 2003) conditions. Since 2006, row crops have followed the same rotation as the LTER Main Cropping System Experiment (MCSE; corn-soybean-wheat); continuous corn was grown from 1999-2005. Nitrogen fertilization rates differ by crop (since 2008) and are given on the plot map.
The experiment moved to its current location in the LTER Main Site in 2005; previous experimental designs and locations are given here
Note
| Experiment: | Resource Gradient Experiment |
| Data available from: | September 2011 to November 2023 |
| Dataset: | KBS033 |
| Datatable ID: | KBS033-005.120 |
| Core Areas | Inorganic Nutrients,Disturbance |
| Repository link: | http://doi.org/10.6073/pasta/b87efd66b937c806061635e752862d8a |
| Related Tables: | |
| Personnel: |
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| Last Updated | 2025-10-03 |
| Variate | Description | Units |
|---|---|---|
| site | experimental site that was sampled | |
| sample date | date the sample was taken | |
| plot | plot number | |
| treatment | treatment where the sample was taken from | |
| replicate | replicate plot the sample was taken from | |
| top depth cm | the top depth of the soil sample | cm |
| bottom depth cm | the bottom of the soil core | cm |
| irrigated | true if the plot is irrigated, false if it is not | |
| ph | pH measured | |
| p | Bray P1 phosphorus in ppm | mg/kg |
| k | potassium in ppm | mg/kg |
| ca | calcium in ppm | mg/kg |
| mg | magnesium in ppm | mg/kg |
| lime index | the lime index | |
| cec | estimated cation exchange capacity meq/100g | |
| z ppm | zinc in ppm | mg/kg |
| s ppm | sulfur in ppm | mg/kg |
| b ppm | boron in ppm | mg/kg |
| lab | the lab that performed the anlysis | |
| om loi | percentage of soil organic matter measured by loss on ignition | % |
| p m3 | phosphorus Mehlich in ppm | mg/kg |
| k percent | % | |
| mg percent | % | |
| ca percent | % | |
| h percent | % |
Data Excerpt
| site | sample_date | plot | treatment | replicate | top_depth_cm | bottom_depth_cm | irrigated | ph | p | k | ca | mg | lime_index | cec | z_ppm | s_ppm | b_ppm | lab | om_loi | p_m3 | k_percent | mg_percent | ca_percent | h_percent |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Resource Gradient Experiment | 2025-09-23 | 103 | F3 | R1 | 0 | 25 | false | 6.0 | 25.0 | 90.0 | 700.0 | 120.0 | 5.9 | A&L Great Lakes Laboratories, Inc | 1.4 | 34.0 | 3.9 | 16.9 | 59.0 | 20.2 | ||||
| Resource Gradient Experiment | 2025-09-23 | 104 | F4 | R1 | 0 | 25 | false | 5.8 | 24.0 | 93.0 | 650.0 | 105.0 | 5.6 | A&L Great Lakes Laboratories, Inc | 1.4 | 33.0 | 4.3 | 15.7 | 58.4 | 21.6 | ||||
| Resource Gradient Experiment | 2025-09-23 | 101 | F1 | R1 | 0 | 25 | false | 5.8 | 28.0 | 138.0 | 550.0 | 90.0 | 5.1 | A&L Great Lakes Laboratories, Inc | 1.5 | 39.0 | 7.0 | 14.8 | 54.4 | 23.7 | ||||
| Resource Gradient Experiment | 2025-09-23 | 102 | F2 | R1 | 0 | 25 | false | 6.1 | 29.0 | 119.0 | 650.0 | 115.0 | 5.7 | A&L Great Lakes Laboratories, Inc | 1.3 | 39.0 | 5.3 | 16.8 | 56.9 | 21.0 | ||||
| Resource Gradient Experiment | 2025-09-23 | 105 | F5 | R1 | 0 | 25 | false | 5.6 | 23.0 | 103.0 | 600.0 | 90.0 | 6.4 | A&L Great Lakes Laboratories, Inc | 1.5 | 32.0 | 4.1 | 11.7 | 46.8 | 37.4 |