Photogrammetry for assessment of pasture biomass

Authors

  • Kathryn Wigley Lincoln Agritech
  • Jennifer L. Owens Agriculture and Agri-Food Canada
  • Matthias Westerschulte Lincoln Agritech
  • Paul Riding Lincoln Agritech
  • Jaco Fourie Lincoln Agritech
  • Armin Werner Lincoln Agritech

DOI:

https://doi.org/10.33584/jnzg.2019.81.394

Abstract

New tools are required to provide estimates of pasture biomass as current methods are time consuming and labour intensive. This proof-of-concept study tested the suitability of photogrammetry to estimate pasture height in a grazed dairy pasture. Images were obtained using a digital camera from one site on two separate occasions (May and June 2017). Photogrammetry-derived pasture height was estimated from digital surface models created using the photos. Pasture indices were also measured using two currently available methods: a Rising Plate Meter (RPM), and Normalised Difference Vegetation Index (NDVI). Empirical pasture biomass measurements were taken using destructive sampling after all other measurements were made, and were used to evaluate the accuracy of the estimates from each method. There was a strong linear relationship between photogrammetry-derived plant height and actual biomass (R2=0.92May and 0.78June) and between RPM and actual biomass (R2=0.91May and 0.78June). The relationship between NDVI and actual biomass
was relatively weaker (R2=0.65May and 0.66June). Photogrammetry could be an efficient way to measure pasture biomass with an accuracy comparable to that of the RPM but further work is required to confirm these preliminary findings.

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Published

2019-10-22

How to Cite

Wigley, K., Owens, J. L., Westerschulte, M., Riding, P., Fourie, J., & Werner, A. (2019). Photogrammetry for assessment of pasture biomass. Journal of New Zealand Grasslands, 81, 33–40. https://doi.org/10.33584/jnzg.2019.81.394

Issue

Volume 81, 2019, Napier

Section

Vol 81 (2019)

License

Copyright

This work is licensed under a Creative Commons Attribution-Non Commercial-NoDerivatives 4.0 International License. Rights granted to the New Zealand Grassland Association through this agreement are non-exclusive. You are free to publish the work(s) elsewhere and no ownership is assumed by the NZGA when storing or curating an electronic version of the work(s). The author(s) will receive no monetary return from the Association for the use of material contained in the manuscript. If I am one of several co-authors, I hereby confirm that I am authorized by my co-authors to grant this Licence as their agent on their behalf. For the avoidance of doubt, this includes the rights to supply the article in electronic and online forms and systems.

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