Optical and Thermal Remote Sensing of Turfgrass Quality, Water Stress, and Water Use under Different Soil and Irrigation Treatments

Saleh Taghvaeian,Mark Crookston,Mary Hattendorf,José Chávez

doi:10.3390/rs5052327

Abstract

Optical and thermal remote sensing data were acquired at ground level over several turfgrass species under different soil and irrigation treatments in northern Colorado, USA. Three vegetation indices (VIs), estimated based on surface spectral reflectance, were sensitive to the effect of reduced water application on turfgrass quality. The temperature-based Grass Water Stress Index (GWSI) was also estimated by developing non-transpiring and non-water-stressed baselines. The VIs and the GWSI were all consistent in (i) having a non-linear relationship with the water application depth; and, (ii) revealing that the sensitivity of studied species to water availability increased in order from warm season mix to Poa pratensis L. and then Festuca spp.. Implemented soil preparation treatments had no significant effect on turfgrass quality and water stress. The differences between GWSI-based estimates of water use and the results of a complex surface energy balance model (METRIC) were not statistically significant, suggesting that the empirical GWSI method could provide similar results if the baselines are accurately developed under the local conditions of the study area.

Highlights

In recent decades, a fast population growth along with high rates of urbanization has exacerbated the pressure on water managers to meet urban water requirements
38% of the incident radiation in NIR waveband was reflected on average, an indication of large number of hydrated cell walls and air cavities in the mesophyll tissue of turf blades
All turfgrass species that received higher rates of irrigation were darker in color

Summary

Introduction

A fast population growth along with high rates of urbanization has exacerbated the pressure on water managers to meet urban water requirements. Such a pressure is substantially greater for municipalities in arid/semi-arid regions (e.g., western USA), where water resources are scarce and in high demand. Boland [1] argued that since freshwater is over-allocated in many parts of the world and it is not feasible to make new water resources available, the best solution to mitigate possible consequences of climate change relies in demand management rather than in supply development. Demand management is less time and money consuming and less dependent on the uncertain effects of climate change [1]

Methods

Results

Conclusion