Bryce Rampton discusses the importance and how to properly perform a flag test in your soybean crop.

Transcript

Even soybean emergence is critical to get the most out of your crop. In this video Bryce Rampton, product development agronomist, explains that the ideal scenario is for all plants to emerge within a 48-hour window. When they emerge at the same time and with uniform spacing, plants can optimize the available resources to produce high yields. When emergence is spread out over four or more days, those later-emerged plants can’t catch up. In fact, they end up competing with other plants for sunlight, moisture and nutrients.

Rampton recommends a flag test as a valuable tool to evaluate emergence in order to determine if changes to planting equipment or practices are necessary for future seasons. 

To conduct a flag test, follow these steps:

1. Identify the monitoring area. After planting and prior to emergence, measure off 100 feet of row and stake both ends with tall pin flags. Measuring more than one row across the drill can also provide info on row-to-row performance.
2. Get your flags ready. Source at least five different colours of small wire flags to mark when plants have emerged from the soil.
3. Flag plants as they emerge. About five to 15 days after planting, cotyledons will begin to crack through the soil. Once they are fully above the soil surface (VE), select the first coloured flag and place it next to the emerged plant. Repeat this step for all plants at VE stage that day. 
4. Return to the site daily to flag newly emerged plants. Place a different coloured flag beside newly emerged plants until you are confident that all viable plants have emerged. Be sure to document the number of days after planting that each flag colour represents.
5. Analyze planting quality between V1 and V3, or when all plants have emerged. Count the number of flags of each colour and determine a percent total for each colour to understand the progression of emergence. Measure the distance between plants to assess the quality of singulation. Assess gaps in the row for lack of seed, unviable seed and dead seedlings.
6. Leave flags in place until R8 (full maturity). At this point, you will be able to analyze the effect emergence date had on final plant height, pod number, seeds per pod, number branches, etc.

For more information, review this Soybean Flag Test instructional document.