Earlier Planting Date and Decreased Population Impacts on Full Season Early Maturity Soybeans
Sustainable Production
DiseaseField management Pest
Lead Principal Investigator:
Nicole Fiorellino, University of Maryland
Co-Principal Investigators:
Project Code:
Contributing Organization (Checkoff):
Institution Funded:
Brief Project Summary:
The start of indeterminate soybean reproductive stages depends on the detection of the length of night. Due to this, later-planted soybeans do not have as much time to develop leafy growth. Additional photosynthesis from leaves and nodes for pod production can mean additional yield, with more time to grow. However, issues with earlier planting have occurred where cooler, wetter soils slow germination, may cause seeds to rot and permit sudden death syndrome infection. This research compares new varieties of full-season soybeans planted on three different dates, evaluates plots for deficiencies and disorders, and compares tissue and soil contents to yield at the end of the season.
Key Beneficiaries:
#agronomists, #Extension agents, #farmers
Unique Keywords:
#agronomy, #early planting, #planting, #planting date
Information And Results
Project Summary

This project is the first of a multiple year study to evaluate changes to full season soybean planting date and
population and its impact on yield and farmer profitability.

Project Objectives

This project is the first of a multiple year study to evaluate changes to full season soybean
planting date and population and its impact on yield and farmer profitability.

Project Deliverables

To evaluate the yield impacts of combinations of planting dates and planting populations on full season soybeans, we will establish small plots (eight-30” rows wide, length determined by field size) at two University of Maryland Research and Education Centers (RECs), one each on the Eastern Shore and Western Shore, to observe results across different climate and weather. We will utilize two planting dates (early, mid-April, and late, early May), two MG categories (early MG 3, <3.4, and late MG 3, >3.6), three populations (80k, 100k, and 120k seeds per acre), and at least three popular varieties in each MG category from different brands/companies. Each combination will be replicated three times at each location. Project team members will evaluate stand count and branching in season, collect yield via harvest of the center two rows of each plot with Almaco R1 research combine (Almaco Co., Nevada, IA). Grain yield, harvest moisture, and test weight will be measured for each plot. These data will be collected with a Seed Spector LRX system (Almaco Co., Nevada, IA) and recorded on Microsoft xTablet T1600, and profitability calculation based on seed price, yield, and average grain price at the completion of data collection.

We are requesting funds to modify our current John Deere Maxemerge-2 four-row planters, currently set up for 30” row spacing to a five-row 15” spacing planter able to plant into no-till conditions. The smaller between-row spacing will allow for the inclusion of one additional row unit and we will outfit each row with updated row cleaners and closing wheels. The proposed modifications will help align our equipment and field trials to better represent the conditions that MD soybean growers are facing and allow us to generate results that are more representative of MD conditions.

Progress Of Work

The study has been established at the locations listed in the proposal (Wye and Beltsville). Stand counts and branching data have been collected at each location and we are preparing for a timely harvest, barring no major weather events as we move into the fall.


View uploaded report PDF file

Final Project Results

Benefit To Soybean Farmers

The transition from vegetative to reproductive growth in indeterminate soybeans depends on the detection of night length, or number of hours without sunlight as the season continues. As soybeans are planted later into the growing season, they do not have as much time to develop biomass. They also miss the opportunity for longer days and intercepting additional sunlight, to drive photosynthesis towards production of pods – which could decrease yield. The general hypothesis is a longer growing season, and therefore greater photosynthesis, could increase soybean yields. If there is a benefit to early planting, it should be either time savings for the farmer, maybe shifting planting of soybeans before or during corn planting to get it completed earlier, or the benefit should be a financial one, either through increased grain yield or decrease seed cost or both, ideally. Research from across the US has demonstrated soybean yields can be maintained while decreasing planting population, ultimately decreasing seed costs. Therefore, the potential for increased farmer profitability exists.

With the interest in pushing planting dates earlier, we acknowledge that other management decisions must be changes to accompany the earlier planting date; farmers cannot plant soybeans earlier without making other management changes to maximize yields. While nationally research has not demonstrated a clear trend to shifting maturity groups with shifting planting dates, generally, it has been shown that an earlier maturity variety should be used for earlier planting, to ensure flowering while daylight is lengthening, and reproductive development takes place before the hottest temperatures of the
summer. This management scenario presents risks though, as earlier harvest may be necessary to prevent yield losses from shattering or grain damage due to lower moisture content. While early- to mid-MG 4 soybeans generally yield well in Maryland, a shift to a MG 3 soybean may be necessary in this early planting scenario. Therefore, we will evaluate MG 3 varieties in this study, to hone in on where in the MG 3 continuum would yield be optimized at early planting across multiple populations.

We are proposing a multi-year study, with funds requested annually per MSB’s funding cycle, whereby we begin our evaluation under narrowed parameters (MG 3, two planting dates, three populations) in full season soybeans at multiple locations in MD, then shift our focus to double crop soybeans in a similar evaluation. The overall goal of this multi-year study is to provide MD farmers with updated planting recommendations when shifts in planting date must be made.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.