Black Grass Analysis

Geo-4D have been working with MicaSense in order to develop our agricultural services and research new uses for their RedEdge multispectral sensor. Working closely with a local farmer, our team captured data over the 24 acre site with a fixed-wing UAV, before processing the results into an orthomosaic, DSM and several different vegetation indices.

The aim of this project was to allow the farmer to visualise how much black grass was present within the winter wheat crop, where the largest patches were located and to provide them with the information to create a plan of action for the next growing season.

The flight took place in June, and even from the RGB Composite Orthomosaic alone, it was immediately possible to identify the lighter-coloured black grass emerging above the crops. In addition to this, NDVI, NDRE and OSAVI indices were created to allow for further analysis and interpretation of what was and wasn’t black grass. The NDRE layer proved to be the most useful, highlighting a clear difference in the chlorophyll content between the black grass and the wheat crop, which was to be expected as NDVI often loses sensitivity later on in the growing season. The results from the NDRE layer also tied in very well with the interpretation of the RGB Composite layer, and the ground truth information noted by our team on-site.

 

The final results from the project were made available in an online viewer, which allowed the farmer to access the data from a tablet and share it with agronomists, partners, etc. The zones containing black grass were also delineated and exported as shapefiles, which can then be imported into GIS/farm management software and used to assist with planning for future years. 

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