Keeping the K in Carrots: Drone Technology to Uncover Potassium Variations

Optimizing field management of an organic carrot farm in the Netherlands, using drone-acquired multispectral imagery and Pix4Dmapper Ag software...

  • Organization Aurea Imaging
  • Country The Netherland
  • Industry Agriculture
  • Project Date October 2015
  • Project Members Bert Rijk, Anja Hoorweg
  • Project Size 10 Hectares
  • Number of Images 176
  • GSD 12 cm

Project Description

arrots are an important crop in Dutch agriculture, with net yields up to 100 t/ha and a high nutrient requirement, especially for potassium. As farms increase in size and technologies evolve, it pays off to use new technologies for better and more precise management of larger fields.
For this use case, a farmer of organic carrots in the Netherlands and agronomy firm Agrifirm asked Aurea Imaging to acquire multispectral imagery and assist in its analysis and interpretation. The goal was to assess carrot plant health and quickly detect deficiencies or problem areas for improved cultivation.

Data Acquisition

A senseFly eBee fixed wing drone acquired the images using an Airinov Multispec4C camera with sensors in Red, Green, Near-Infrared and Red-Edge bands. A single 15 minute flight in grid pattern had a high frontal overlap of 80% and side overlap of 75%. 176 images at 12 cm GSD were taken at 120m altitude, then processed with results delivered within 24 hours.

Achieved Result

After processing in Pix4Dmapper, an NDRE index map was calculated, highlighting variations on the carrot field.

Two locations, one with high NDRE and one with low NDRE values, were selected for soil sampling. Potassium reserves (K-value), a variable that directly affects the health of the carrots, were measured.

Samples revealed 55 ppm for the good areas (high NDRE) and 9 ppm for the bad (low NDRE), with target carrot K-values being 30-40 ppm.
Fertilizer will be applied according to the soil sampling results, using a shapefile of customized fertilizer application classes for tractor guidance, with low K-value locations receiving a large dose of potassium, and high K-value locations receiving low potassium fertilizer.

Advantage of the New Technology

The NDRE Map, generated from Pix4Dmapperӳ Index Calculator, assisted in selecting soil sampling locations and the discovery of soil potassium variations, which have a potentially large influence on crop growth and quality. This targeted K-fertilization reduced the negative environmental impact of K percolation into groundwater and lowered costs by reducing fertilizer amount. On-site scouting uses visual inspection to assess crop status from the ground. Unfortunately, such ground-based techniques are limited by the viewing angle and spectral constraint of the human eye. Innovative technologies using drones and multispectral imagery have tremendous potential in complementing field scouting and the art of agronomy.


Author: Bert Rijk (Aurea Imaging), Anja Hoorweg (Agrifirm Plant)