While soybean is thought of as a highly competitive and resilient crop, early-season growth and development is critical to maximizing yields. Because soybeans have the potential to produce respectable yields in full, no-till scenarios under heavy corn residue, relatively little attention has been paid to early-season growth and development. While early planting is important, it is early spring vigor and growth rates that determine yield potential. Rainfall patterns have shifted significantly, making very heavy rainfall events more frequent, thus making drainage, tillage, and residue/cover crop research all the more critical.

Here we propose to utilize a wide range of contemporary crop management scenarios to examine many aspects of temperature, water, and nutrient availability and their effects on early planted soybean. We plan to utilize our existing Drainage x Tillage research site near Wells, Minnesota, to investigate the effects of residues on early planted soybean. We will also carefully examine the three-way interactions between residue quantity and quality, tillage, and drainage.

By including residue removal and cover crop treatments, we can investigate the effects of residue level on all aspects of both early-season and season-long soybean growth. We plan a first-of-a-kind experiment to evaluate effects of drainage, tillage, and residue on soil temperatures, moisture, and nutrient availability at the seed, and in the rhizosphere from planting through harvest. Results from this multi-year trial will vastly improve the quality of recommendations regarding fall tillage, cover crop management, and planting management in both well-drained and poorly drained soils.

Set up the U of MN/MSR&PC’s unique site near Wells to examine interactions between Drainage, Tillage, and Residue management.
Objective 1: Plant bulk corn and soybean plots in 2021 to completely eliminate any previous treatment effects
Objective 2: Establish fall tillage, residue, and cover crop treatments in preparation for the 2022 cropping season
Objective 3: Deploy environmental monitoring equipment to examine spring thaw, warm-up, and dry down of the soil profiles

Examine the primary effects of Drainage and Tillage on drivers of spring soil conditions affecting planting, emergence and vigor
Objective 1: Deploy soil monitoring to evaluate soil temperature and moisture profiles after spring thaw through planting to examine soil temperatures and moisture at 2 and 4”
Objective 2: Monitor soil moisture and temperature throughout the profile throughout the growing season
Objective 3: Examine nitrogen availability and mineralization profiles throughout the season

Complete a comprehensive physical, chemical, and biological analysis of the site to evaluate long-term effects of D and T
Objective 1: Measure soil root penetration resistance, bulk density, and water infiltration
Objective 2: Measure total inorganic carbon and nitrogen and total organic carbon and nitrogen
Objective 3: Measure biological parameters related to nitrogen availability: nitrogen mineralization potential and soil microbial community structure by soil phospholipid fatty acid analysis (PLFA)

Updated February 1, 2022:
Soil temperature and water monitoring: We were fully set up to examine both shallow (<12") and deep (0'-24") soil moisture and temperature profiles as affected by tillage and drainage in 2021. However, a couple of issues greatly hindered this work: 1) 2021 was an unprecedented dry year at this site. Due to drought conditions, soil temperature and moisture conditions were extremely anomalous this year. More importantly, though 2) We purchased a complete weather monitoring system in 2021. We purchased an entire system to monitor in each tillage and drainage treatment across all four reps. This system failed to provide reliable data as the sensors continuously went off-line all summer. We worked with the company (ONSET) all summer long, but they could never fix our core issues. We have since returned the entire system and are currently investigating other options for 2022. We have determined that METER environmental monitoring systems will be significantly more robust, and we plan to purchase a system through them this winter.

Practically speaking, this current project has three parts. 1) Soil analysis to evaluate long-term effects of tillage and drainage on soil chemical and physical properties. 2) Evaluation of soil microclimate on soybean emergence, growth, and yield, and 3) Setup for a new multi-year study beginning in 2021.

1) New MS student Carlos Sanchez started in May. He conducted extensive soil sampling and soil testing during the summer season. This work will continue in 2022.
2) Due to failed environmental monitoring equipment, soil and climate data was a bit discontinuous during the crop year. We are currently evaluating this data to determine is value.
3) Adding residue treatments (cover crop, corn residue removal, and control) added a significant amount of work to this project. Logistics for harvest, sampling, tillage, and residue treatments is very complex. We were able to get everything done this fall, however, we were unable to get the cereal rye planted early enough to get good fall growth. We will be dependent on spring growth only in 2021.

4/23/2021 – Tillage
5/1/2021 – Corn and plots planted
5/3/2021 – weather station installed
5/14/2021 – installed 24” sensors
6/14/2021 – root digs – V3 plants – for WinRhizo scans
7/9/2021 – R3 fertilizer applications
7/26/2021 – soil water infiltration measures
9/21/2021 – plant heights and stand counts
10/10/2021 – harvest soybean plots
10/15/2021 – Soil samples
10/18/2021 – Residue removal treatments (with small square baler)
10/26/2021 – Strip till
11/8/2021 – conventional tillage
11/22/2021 – frost seeded cereal ryegrass for a spring cover crop

A poster describing some preliminary results from this trial are attached here. This poster was presented by Carlos Sanchez at the recent international Agronomy meetings held in Salt Lake City, November 7-10, 2021.

View uploaded report

Updated November 22, 2021: