New Zealand Journal of Agricultural Research abstracts

---

Relationship between spectral reflectance and water stress conditions of Bermuda grass (Cynodon dactylon L.)

Namik Kemal Sönmez¹

Yasar Emekli²

Mustafa Sari³

Ruhi Bastug²

¹Akdeniz University
Remote Sensing Research and Application Center
07059 Antalya, Turkey
nksonmez@akdeniz.edu.tr

²Akdeniz University
Faculty of Agriculture
Department of Farm Structure & Irrigation
07059 Antalya, Turkey

³Akdeniz University
Faculty of Agriculture
Department of Soil Science
07059 Antalya, Turkey

Abstract Remotely sensed data is an important tool for precision crop management. Satellite imaging systems and related-hand held instruments are frequently proposed for detection of crop stress caused by water, soil compaction and lack of nutrients, etc. This study was conducted to investigate how Bermuda grass reflectance changes with the onset of water stress. Four different irrigation treatments were examined: 100% (I₁), 75% (I₂), 50% (I₃) and 25% (I₄) of the evaporation measured in the Class A Pan. A non-irrigated plot was used as a control treatment (I₅). Spectral reflectance data were collected using a hand-held spectroradiometer which measured in the blue, green, red and near-infrared. Soil water content was monitored by a neutron probe. Water-stressed Bermuda grass (treatments I₄ and I₅) had lower spectral reflectance in near-infrared and higher reflectance in red wavebands than the other treatments. The results were statistically tested using one-way analysis of variance and Duncan’s multiple range test. Highly significant relationships were found between different irrigation treatments and near infrared wavelengths (P < 0.01, R² = 0.94) and between the irrigation treatments and the normalised difference vegetation index (NDVI) (P < 0.01, R² = 0.80). Results indicate that different water stress on Bermuda grass could be determined by using spectral reflectance, especially NDVI and near-infrared reflectance regions. Analysis of experimental data indicated that it is possible to use remotely sensed data to develop maps of water stress conditions of Bermuda grass (Cynodon dactylon).

Keywords Bermuda grass; NDVI; remote sensing; spectroradiometer; water stress

A07029; Online publication date 15 July 2008; Received 28 April 2007; accepted 24 April 2008

New Zealand Journal of Agricultural Research, 2008, Vol. 51: 223–263
0028–8233/08/5103–0223 © The Royal Society of New Zealand 2008

PDF file of entire paper: Print-quality (992K) | screen-quality (705K)