Interseeded clover into corn: Yield and soil N data
Data files
Sep 16, 2026 version files 62.67 KB
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Dryad_InterseedData.xlsx
58.19 KB
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README.md
4.48 KB
Abstract
Inter-seeding red clover (Trifolium pratense L.) provides an alternative method to incorporate cover crops into continuous corn (Zea mays L.) in the Upper US Midwest. Red clover is a leguminous cover crop that can grow in low-radiation environments and is winter-hardy. Systems with red clover have demonstrated improved corn yield and a fertilizer N equivalence, but understanding these effects with inter-seeding warrants further investigation. The objectives of this study were to determine the effect of inter-seeding red clover on (i) plant-available N during and after red clover decomposition, (ii) optimum N rates for corn, and (iii) corn yields. The experimental design was a randomized, complete block-split plot design, with cover crop as the main plot factor (treatments with and without inter-seeded red clover) and N-rate as a split-plot factor (N-rates between 0 and 315 kg-N ha−1 in 45 kg-N ha−1 intervals). Quadratic plateau response curves with a bootstrapping technique were used to determine differences in optimum N rate among treatments. Corn yields were evaluated with or without red clover inter-seeded following the first inter-seeding year. Red clover accumulated biomass values of 50 kg ha−1 up to 300 kg ha−1 pre-termination when inter-seeded with corn at the V4–V5 growth stage without detriment to yield. Corn yield was improved with clover treatments in one of four site years tested, resulting in a (15–17 kg ha−1) lower N requirement that year. Overall, our results indicate that inter-seeding red clover into continuous corn did not provide an agronomically meaningful nitrogen fertilizer equivalence to the cropping system.
Dataset DOI: 10.5061/dryad.zs7h44jsk
Description of the data and file structure
This data set contains soil nitrogen values and corn yield values with and without interseeded red clover in a continuous corn system. These data accompany the publication "Nitrogen fertilizer equivalence of red clover when inter-seeded into corn". All measurements were collected at the Arlington Agricultural Research Station in Arlington, Wisconsin, between 2017-2020. Soils were analyzed at the University of Wisconsin Soil and Forage Analysis Laboratory.
Files and variables
File: Dryad_InterseedData.xlsx
Description: Excel document with a "Yield" tab, a "Soil N_averages" tab, and a "Soil N_Raw" tab.
Variables with descriptions: Each variable below has a short description with the measurement descriptions in one column and accompanying codes used in the data set in the second column.
Sampling Time - time of year when samples were taken. Time windows detailed below. Exact dates provided in the methods in the text.
| Sampling Time | Code (character) |
|---|---|
| Fall (early November) | Fall |
| Early Spring (late May) | Spring1 |
| In-season late spring (late June) | Spring2 |
Year - the calendar year of the expirment. Experimental data was collected 2017-2020.
| Year | Code (numeric) |
|---|---|
| 2017 | 2017 |
| 2018 | 2018 |
| 2019 | 2019 |
| 2020 | 2020 |
Whole plot treatments - treatment codes for the complete block split plot experimental design. "Clover Always" was a treatment with red clover inter-seeded every year. "Clover planted the year prior" had data collected in treatments that had clover growing the previous year, but not the current year. "No clover" treatments never had clover growing. "Reference rye" was a ceral rye cover crop that was grown adjacent to the experimental fields and used as a reference plant for nitrogen dynamics with red clover.
| Whole plot treatments (complete block) | Code (character) |
|---|---|
| Clover Always | Clover |
| Clover planted the year prior | Clover_YP |
| No Clover | None |
| Reference Rye | Rye |
Split plot treatments - treatment codes for the split-plot nitrogen (N) fertilizer rates in kg N ha1
| Split plot N fertilizer rate (kg N ha-1) | Code (numeric) |
|---|---|
| 0 | 1 |
| 45 | 2 |
| 90 | 3 |
| 135 | 4 |
| 180 | 5 |
| 225 | 6 |
| 270 | 7 |
| 315 | 8 |
Block - the block replicates in the complete plot split plot experimental design. There were four replicates for each treatment.
| Block | Code (character) |
|---|---|
| 1 | Rep 1 |
| 2 | Rep 2 |
| 3 | Rep 3 |
| 4 | Rep 4 |
| 5 | Unreplicated interseeded reference rye with N |
| 6 | Unreplicated interseeded reference rye no N |
Depth - Sampling depth for soil samples (cm) taken with a soil corer. At least 6 subsamples per plot were homogenized into treatment-level soil samples.
| Depth (cm) | Code (numeric) |
|---|---|
| 0-15 cm | 1 |
| 0-30 cm | 2 |
| 30-60 cm | 3 |
Code/software
Excel or other spreadsheet reader is required to view this data set.
Access information
Other publicly accessible locations of the data:
- NA
Data was derived from the following sources:
- NA