Identification of plant leaf phosphorus content at different growth stages based on hyperspectral reflectance

BMC Plant Biol. 2021 Jan 7;21(1):28. doi: 10.1186/s12870-020-02807-4.

Abstract

Background: Modern agriculture strives to sustainably manage fertilizer for both economic and environmental reasons. The monitoring of any nutritional (phosphorus, nitrogen, potassium) deficiency in growing plants is a challenge for precision farming technology. A study was carried out on three species of popular crops, celery (Apium graveolens L., cv. Neon), sugar beet (Beta vulgaris L., cv. Tapir) and strawberry (Fragaria × ananassa Duchesne, cv. Honeoye), fertilized with four different doses of phosphorus (P) to deliver data for non-invasive detection of P content.

Results: Data obtained via biochemical analysis of the chlorophyll and carotenoid contents in plant material showed that the strongest effect of P availability for plants was in the diverse total chlorophyll content in sugar beet and celery compared to that in strawberry, in which P affects a variety of carotenoid contents in leaves. The measurements performed using hyperspectral imaging, obtained in several different stages of plant development, were applied in a supervised classification experiment. A machine learning algorithm (Backpropagation Neural Network, Random Forest, Naive Bayes and Support Vector Machine) was developed to classify plants from four variants of P fertilization. The lowest prediction accuracy was obtained for the earliest measured stage of plant development. Statistical analyses showed correlations between leaf biochemical constituents, phosphorus fertilization and the mass of the leaf/roots of the plants.

Conclusions: Obtained results demonstrate that hyperspectral imaging combined with artificial intelligence methods has potential for non-invasive detection of non-homogenous phosphorus fertilization on crop levels.

Keywords: Hyperspectral imaging; Phosphorus fertilization; Precision agriculture; Supervised classification.

Publication types

  • Comparative Study

MeSH terms

  • Apium / chemistry*
  • Apium / growth & development
  • Beta vulgaris / chemistry*
  • Beta vulgaris / growth & development
  • Carotenoids / analysis
  • Chlorophyll / analysis
  • Crop Production / methods*
  • Crops, Agricultural / chemistry
  • Fertilizers*
  • Fragaria / chemistry*
  • Fragaria / growth & development
  • Hyperspectral Imaging / methods
  • Phosphorus / analysis*
  • Plant Leaves / chemistry*

Substances

  • Fertilizers
  • Chlorophyll
  • Phosphorus
  • Carotenoids