Making Better Herbicide Decisions with Weed Density Mapping

Proper weed control early during the growing season is essential for reducing nutrient competition, gaining optimal crop health, and preventing yield loss. Weed management in corn and soybeans can be an extremely difficult problem to tackle and, if left unmanaged, can cause nearly a 52% corn yield loss and 49% yield loss in soybeans according to research conducted by the Weed Science Society of America and Kansas State University.

For decades, herbicide use has proven to be effective, but resistant weeds have created challenges for this management practice. When pre-emergent herbicide resistance or delayed planting occurs, Sentera’s FieldAgent™ weed density mapping analytics can provide users with an exact snapshot of weed pressure and location in a field. Utilizing the weed density mapping analytics tool empowers growers to save time, reallocate inputs, and create treatment prescriptions with better precision.

How it Works

FieldAgent weed density maps use computer vision technology to accurately identify location and density of weeds, capturing 100-times more measurements than manual scouting. This technology provides growers with an accurate count of weeds by analyzing every pixel of every captured image and accurately identifies the location and density of weeds in the field.  FieldAgent transforms the results into a color-coded map, giving an exact snapshot of weed pressure.

At the field edge without an internet connection, results are delivered in a color-coded map containing precise weed location data that can be exported to your favorite prescription writing tool. The result – FieldAgent saves you time and money when finding yield-robbing weeds.

Complete Picture, Better Control

It may only take 2-3 weeks for weeds to reach 4 inches in height and can start to grow several inches per week, which is when they have their greatest impact on yield. Another factor to consider is the short time window for herbicide usage. If a field is flown using FieldAgent’s weed density mapping tool during the critical period of weed control (CPWC), growers may still have time to implement a post-planting weed management plan. In fact, the weed density mapping tool can detect weeds as small as 2 inches in diameter, allowing you the make more precise herbicide decisions during the CPWC.

The chart below, from the University of Nebraska, illustrates the cost of delaying weed control in soybeans.

Let’s look at the cost of delaying weed management at the V2 soybean stage with 30-inch row spacing:

Target yield: 60 bu/acre
After 10% yield loss: 54 bu/acre
Market price: $9.00/bu
Profit loss: $54/acre

As you can see from the chart, the yield loss potential becomes exponential after the 5 percent yield loss threshold. According to the University of Nebraska, you can expect a 2 percent yield loss per leaf stage after this point, potentially increasing your profit loss to over $300/acre if weeds are left uncontrolled through the R3 stage.

An investment in a Sentera complete solution (drone, sensor, FieldAgent subscription, and weed density mapping analytics) is approximately $6,000, depending on the option you choose, with an approximate FieldAgent $1,500/year subscription renewal. Assuming an herbicide cost of $35/acre, the investment pays for itself in the first year alone on half section, or 320 acres of soybeans. As you continue to make your business goals for the 2020 growing season, Sentera is the perfect solution to help you meet them.