Uniform emergence is often cited as the hallmark step to reaching higher yield goals. If you can get all the plants up within 48 hours of each other, uniformity is optimized and the chance of each plant setting a uniform ear is increased. This should theoretically lead to increased yield.
Studies have shown that within a 3-4 day timeframe late emerging plants were NOT considered a weed. Other studies showed that plants at a 2 leaf delay would result in less yield.
In 2017 we found that 74% of yield was attributed to plants emerging within the first 24 hours. In 2018 we found that 54% of yield was attributed to plants emerging within the first 24 hours. Plants showed a 2-6% yield reduction for those emerging after 24 hours. Plants showed a 1-3% yield reduction for those emerging after 24 hours but before 48 hours. However, plants emerging between 24 and 48 hours still contributed to overall yield.
Variable rate technologies have been developed as a means of intensifying management with the goal of increasing yield and reduce costs. The process for deriving value from variable rate seeding starts with good management zones. These can be based on soil type, yield history, topography, and electrical conductivity. Our goals for corn and soybean variable rate seeding are a little different. With corn we are looking to vary populations to match the yield potential across the field. With soybeans we are looking to vary populations across the field in an attempt to get a more uniform emerged population across the whole field. We do this by increasing population in “tougher” portions of the field and decreasing populations in portions of the field where we typically have more uniform and consistent emergence. While we are making these recommendations with more confidence, we find it important to test various seeding rates in a variety of soil and environmental conditions. The following study helps us test each year what optimum seeding rates should be in various environmental conditions, whether you are using VRS or a single rate across your fields.
Soybean Planting Date Study
Industry and University studies alike have heralded the benefit of planting soybeans early. Studies have shown that pushing the planting back date with the goal of having a larger leaf area to harvest more light at the point in July where they are just reaching R3 can help set additional bushels. We were curious about these findings in our environment and geographic conditions, so we set up a study to test these facts.
Soybean Fungicide Study
Use of foliar fungicides in soybeans has been shown to improve crop health in soybean varieties susceptible to various fungal diseases. This improvement in crop health can result in a 2.6 bushel per acre increase in yield. When insecticide was included in treatment, response increased to 5.3 bushels. (Pioneer) Many factors must be considered before choosing to apply a foliar fungicide. These include current and forecasted humidity levels, amount of rainfall, and type and amount of residue from the previous crop. Additionally, type of disease present is important in soybeans. Diseases originating in the root system will not be controlled with fungicides. Neither will diseases stemming from bacterial or viral diseases such as bacterial blight or soybean vein necrosis.
Fungicides will be effective on fungal diseases for 14-21 days after application. Applications are usually timed to ensure this timeframe for protection falls between pod set and maturity to protect the reproductive stages of the growing season. Generally, we shoot for applications around R3, which is the start of pod development. Some research from the University of Illinois suggests that a single application at R3 is just as effective as two applications at R3 and R5. Other research from BASF suggests that two fungicide applications are beneficial. We wanted to discover what the average response in our geography is. Over the past 4 years, we have tested fungicide trials across the county to see what kind of response we can see in a typical year.