DOI: 10.5061/dryad.34tmpg4v8
title: Data from: Soybean yield is positively linked to organic matter, but planting date remains more influential

description: Establishing connections between soil health indicators and crop
 performance will help ensure that tests recommended to farmers relate to
 outcomes of interest. This study assessed the relationship of soybean
 [Glycine max (L.) Merr] yield with three common soil health indicators:
 soil organic matter (SOM), permanganate oxidizable carbon (POXC), and
 autoclaved citrate extractable nitrogen (ACE‐N). These tests were assessed
 alongside other factors (soil test phosphorus, soil test potassium [STK],
 mapped clay, planting date, summer precipitation, and location). Soil
 samples were collected from 457 producer‐managed fields between 2019 and
 2021 in Arkansas, Michigan, North Carolina, and Wisconsin. Planting date
 and yield were reported by producers, while mapped clay and rainfall were
 determined using publicly available data. Simple linear regression was
 used to assess the relationship between soil health indicators and yield:
 the natural log of SOM and POXC were positively associated with soybean
 yield (R2 = 0.07, p &lt; 0.001; R2 = 0.03, p &lt; 0.001), while
 ACE‐N was not (p = 0.872). Multiple linear regression was used to further
 test the relationship of SOM and POXC with yield, while accounting for
 other factors that contribute to soybean yield. Models explained 27% of
 variation in yield, with significant factors including SOM or POXC,
 soybean planting date, STK, and mapped clay. Based on standardized
 coefficients, planting date was the most influential factor associated
 with yield. Broadly, our results indicate that improvements in yield are
 linked to higher SOM, but management decisions like planting early are
 critical for achieving high yields.
description: # Data from: Soybean yield is positively linked to organic matter, but
 planting date remains more influential
 [https://doi.org/10.5061/dryad.34tmpg4v8](https://doi.org/10.5061/dryad.34tmpg4v8) ## Description of the data and file structure This study looked at the relationship of soybean yield and soil organic matter (and other soil health tests) on 457 farmer fields. ### Files and variables #### File: Dataset\_forRepository11\_20\_24.xlsx **Description:** Each sample is from one field. As coordinates of each field would be identifying information for participating farms, locations are included based on US Counties. ##### Variables * | Collumn Name | Description & Units | | :------------ | :---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Year | Year of sampling and crop yield | | State | US State Name (or region, a small number of Wisconsin samples were in surrounding states) Abbreviations are as follows, AR = Arkansas, MI = Michigan, NC = North Carolina, WI = Wisconsin | | Soybean Yield | Farmer reported soybean seed yield, in kilograms per hectare | | Planting Date | Farmer reported planting date, in day-of-year format | | Summer Precip | The sum of June, July, and August precipitation from Daymet’s monthly climate summaries on a 1 km grid, in millimeters | | pH | soil pH  | | STP | Bray-1 soil test phosphorus, in milligrams per kilogram of soil | | STK | Bray-1 soil test potassium, in milligrams per kilogram of soil | | Percent Clay | Percent clay in top 15 cm, determined through Web Soil Survey | | OM-LOI | Organic matter loss on ignition, in % | | POXC | Permanganate oxidizable carbon, in milligrams per kilogram of soil | | ACE-N | Autoclave citrate extractable nitrogen, in grams per kilogram of soil | | County | U.S. County name, in lieu of coordinates. Coordinates would identify study participants (the 12 samples in Wisconsin border states have their state in parentheses)  | ## Code/software Microsoft excel or another spreadsheet software is needed to view this data. ## Access information Data was derived from the following sources: * Generated data in a laboratory * Daymet * Web Soil Survey