Research Accomplishment Reports 2009

Determining Impact of Lower Soybean Plant Populations on Other Practices within the Soybean Production System

C. Lee
Department of Plant and Soil Sciences

 

Non-Technical Summary

$28 to $32/acre, depending on soybean seed size and seeding rate. If additional data supports the initial findings, then farmers could save a significant amount of money. The purpose of this project is to determine if lower soybean populations can produce high yields while reducing input costs.

2009 Project Description

Soybean varieties were seeded at a range of populations at Lexington, New Haven and Hopkinsville, KY this season. Growing conditions and yields for 2009 were excellent, but optimum plant populations for full season soybeans remained near 100,000 seeds/a (247,000 seeds/hectare). Other studies were initiated to look at numerous inputs on soybean to see if any would increase yield. All inputs alone did not increase yield, but all inputs with higher seeding rates increased yields. Unfortunately in these studies, we did not have the higher seeding rates without the additional inputs. However, the data from this season would suggest that the combination of more inputs (seed treatment, fungicide treatment, foliar fertilizer and higher seeding rates) could increase yield. Preliminary economic analyses indicate that these yield increases are not enough to offset the costs from the additional inputs. This season, 2009, was an extremely good year for soybean production. We will investigate both of these studies again in 2010.

2009 Impact

These are ongoing studies, but the seeding rate trials tend to support earlier research. Farmers who reduce seeding rates by 40,000 seeds/acre (difference between "normal" seeding rate and our recommended seeding rate) will not reduce yields, based on our research. In addition, they will save about $12 to $15 per acre in production of soybean. Again, since yields are not reduced, the farmer actually nets an additional $12 to $15 per acre.