Collecting data on the farm is almost as common these days as complaining about the weather. Putting that data to work to enhance crop performance and yields is critical as margins tighten and you still strive for higher yields.
Advances in mapping technology have proven to be an effective tool in many aspects of farming operations, including when used as a part of weed management efforts. However, there’s much more to managing weeds — and determining whether or not fall weed control is needed — than just looking at some maps of your cropland. How you collect, interpret, utilize and act upon the information you’ve gathered are also important steps.
Marking for weeds
“You can use technology to mark points in the field where weed problems exist and then follow up with a fall application,” says Mark Licht, a cropping systems specialist at Iowa State University Extension. “But you also need to connect it to yield numbers and determine whether or not there were decreases; and then follow up the next spring with spot-specific applications.”
According to Licht, whether you do fall applications is dependent on a number of variables, including where you’re located (geographically) and how long the growing season is, though the use of mapping imagery can certainly help in the decision-making process. He says satellites, airplane flyovers and unmanned aerial vehicles can all be used to capture high-resolution, accurate imaging, but he indicates that the use of Normalized Difference Vegetation Index, or NDVI, technology — with its ability to distinguish between healthy and unhealthy tissue — is one of the most common technologies used.
But even with many imagery choices available, Licht reminds everyone nothing is perfect, especially when it comes to using the technology to help determine the necessity for fall applications.
“We have the technology and resolution quality available to allow people to do stuff on their computer screens, but it won’t necessarily tell you the whole story,” he explains. “You still might need to go out in the field and check things, because ground truthing is still important.”
Ground truthing not only allows you to see potential levels of infestation firsthand, but also helps you identify weeds in the field. According to Licht, this is an important step in the whole process, because knowing what species you’re dealing with will help you determine if it’s a weed that will come back and cause a problem in the spring.
“The technology today allows you to see things in great detail, so using maps to determine the size and scope of a problem area is a good first step,” says Licht, who explains imagery technology has improved a lot over the last five years, which has led to an increased interest in its use.
“I think mapping and imaging is becoming more of a viable option for growers because the technology has gotten so good, [and] it has also gotten much more inexpensive,” he concludes.
Mapping trouble spots is a simple tool for managing tough weed control areas in the field. Adding yield and other layers to the map to determine profit impact will help you refine your weed management program for the future.
Yontz writes from Urbandale, Iowa.
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