Measuring Water Content in Vegetation

To accurately estimate vegetation health, it’s important to measure water content. Water stress negatively affects plant growth and health, cutting back on photosynthesis efficiency. In most cases, researchers look at water content on a leaf/variety basis. A portable field agricultural spectrometer like the PSR+ allows researchers to measure water content/stress in the field without affecting the sample. The PSR+ is a full range (350-2500nm) NIR field portable spectroradiometer with high resolution and high sensitivity for clear and accurate spectra. Using the PSR+, spectra are collected quickly, accurately and without sample preparation. The spectra can exhibit main water absorption features including the most pronounced at 1450nm and 1950nm. In addition less prominent but easily recognized features between 400-700nm can also be analyzed. All data is saved as ASCII files for use with 3rd party analysis software like R or ENVI. The PSR+ and all Spectral Evolution spectroradiometers include DARWin SP Data Acquisition software with 19 vegetation indices, including the Normalized Difference Water index (NWDI) and Water Band Index (WBI). The indices are accessed from pull down menus in DARWin. Leaf spectra can be collected using our unique leaf clip which features a reversible plate with one side for white reference measurements and the other for leaf reflectance. The leaf clip includes a built-in light source that is kept away from the sample so no heat-related problems occur to damage the sample.

Download a technical paper on maize foliar water stress levels by clicking here.

The PSR+ is designed for field use in vegetation reseaerch. The unit is lightweight and portable with two Li-ion batteries for a full day in the field, and no moving optical parts to breakdown. High resolution and unmatched sensitivity (NER specifications) make the PSR+ the spectroradiometer of choice for critical field work, including measuring water content in leaves with our leaf clip.

DARWin SP Data Acquisition software is included with every spectrometer and spectroradiometer. DARWin includes a pulldown menu for access to 19 vegetation indices including NDVI, NDWI, and WBI.