Soybean planting date and tillage interactions for variable rate seeding across management zones
Sustainable Production
Field management Soil healthTillage
Lead Principal Investigator:
Missy Bauer, B&M Crop Consulting
Co-Principal Investigators:
Project Code:
Contributing Organization (Checkoff):
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Brief Project Summary:

Many soybean planters being purchased by farmers today are equipped with the ability to vary the seeding rate as they go across the field. The idea of variable rate planting in soybeans may allow farmers to fine tune their plant populations based on management zones within a field. The foundation of the variable rate is that highly productive soils may produce adequate yields with lower plant populations and medium to poor productive soils may need higher plant populations to optimize yield. Previous studies with B&M Crop Consulting have shown an agronomic and economic improvement with variable rate soybean planting across management zones, but some environments seem to respond to higher...

Unique Keywords:
#soil and tillage management
Information And Results
Final Project Results

Updated October 14, 2019:

The early planting date increased yields on average 3.1 to 4.8 bu/ac. The earlier planting dates resulted in reaching 75% emergence 10 to 19 days sooner than the late planting date. The V1 growth stage was reached 7 to 16 days sooner than the late planting. The sooner V1 is reached the more opportunity for a higher total number of nodes on a plant. The early planting dates increased canopy closure 4.6 to 15 days sooner than the late planting dates. An earlier calendar date of canopy closure will improve total light capture and potentially lead to increased yields. The number of pods and seeds per plant was increased in 3 out of the 4 site locations with the early planting date compared to late planting. The increase in pods came from an increase in nodes per plant or an increase in the number of pods per node depending on the location. In the one site year location where pods and seeds per plant were not increased with early planting date, final populations were a driving factor instead.

Vertical tillage increased yields in both the early and late planting date averaging 2.0 bu/ac across the site year locations. The early planting date averaged 4.1 bu/ac increase across the locations in 2017 and 2018. The overall objective was to determine if the VRA prescription should be changed based on planting date and tillage. The best economical treatment across the site year locations was early planting with vertical tillage and the lower average population (VRA B). In comparing early planting vertical tillage with VRA B to planting late in no-till with VRA B; yields increased an average of 6.7 bu/ac across the site year locations. If planting late, vertical tillage and higher populations were important and increased yields an average of 3.2 bu/ac compared to no-till with lower populations. Population should be adjusted based on planting date by increasing population with later dates. Tillage was not consistently influenced by population. However, in the late planting dates, the no-till treatments did have higher yields with VRA A prescription but it was not always economical. Although in 2017, which was a cooler early growing season, it was economical to have the higher prescription in no-till with the late planting date.

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.