How drones can help counteract grass lodging

Grass lodging often appears in the same places in the field year after year, which is why the researchers behind the project got the idea that they can use drones to find out exactly where these areas are. In this project, scientists measured grass lodging up to 5 years in a row, in order to collect data and find the plots that were most exposed.

Too much fertiliser

“You often see grass lodging in places in the field where there has been applied too much fertiliser. There may be double fertiliser when the tractor turns at the end of the field or when it crosses another track. In such cases, the farmer will be able to make a different fertiliser strategy when he has a complete picture of the risk areas of the field,” said Associate Professor René Gislum from the Department of Agroecology at Aarhus University.

Height as an indicator

Using satellite imagery wasn’t possible, Gislum said, since high resolution imagery is needed to identify grass lodging. Drones proved to be the perfect tool for the job. Gislum said height was used as an indicator, and they looked at a lot of different field trials or plots across years, varieties and treatments to get as much variation in data as possible.

Plots were divided into three different levels of grass lodging:

1. No or little grass lodging (0-30%)
2. Medium grass lodging (30-70%)
3. Heavy grass lodging (70-100%)

Potential for precision agriculture

Gislum said the study can be used in precision agriculture to generate maps of grass lodging and thereby increase seed grass yield at farm level.

“It should be noted that we used grass as a model crop and it cannot be applied directly to other crops. Different crops have different properties, just as the effects on yield may also vary. In the future, we will continue to develop our models to cover more years, so that we can make the model even more robust,” concludes René Gislum.