Evaluation of Potential Inputs to Improve Late-planted Soybean Yield
Limited research is performed on late-planted soybean and farmers are actively seeking information on what input(s) will provide the most value to his/her operation when soybean is planted late.
The objective of this trial was to evaluate the impact that potential inputs have on the yield potential of late-planted soybean.
This study was comprised of ten treatments in a randomized complete block design with three replications. Four treatments added one component to the base management (BM) treatment as indicated with a ‘+’ and four treatments removed one component from the high management (HM) treatment as indicated with a ‘-‘ (Table 1).
A 2.7 MG soybean product was planted in all treatments. • Row spacing was 30 inches.
Weeds were uniformly managed.
Hero® insecticide at 5 fl oz/acre was applied across all treatments at R6 to control salt marsh caterpillars, except the HM-InFu treatment.
Good yields were obtained with the BM treatment considering that the soybean was planted six weeks past the optimum planting date of the first week in May.
Increasing the seeding rate, adding sulfur and zinc, or applying a fungicide and insecticide all had similar yield increases over the BM treatment.
Diseases, such as septoria brown spot or anthracnose, could be controlled with a fungicide.
Insects, such as wooly bear caterpillars, grasshoppers, or bean leaf beetles, could be controlled with an insecticide.
Potassium thiosulfate reduced yield and the most visual symptom was severe burning of the leaves. Potassium provided a positive yield response in 2017, but in that year, potassium was applied as potassium chloride to the base of the plants rather than using a foliar application, as was done in this trial.
It is important to note that potassium thiosulfate can be safely applied but too high a rate was used with too little water and the fertilizer damaged the soybean plants.
The HM treatment yielded more than the BM treatment.
The highest yield in the study was obtained when removing the potassium thiosulfate treatment from the HM system, because the crop was not damaged by the foliar fertilizer application.
Reducing the seeding rate from 180,000 to 120,000 seeds/acre, or removing the insecticide and fungicide application equally reduced yields compared to the HM treatment.
What Does This Mean for Your Farm?
In late-planted soybean, the addition of a fungicide and insecticide or planting a higher seeding rate of 180,000 seeds/acre consistently provided higher yields and greater returns to the soybean production system.