RGB Vegetation Indices, NDVI, and Biomass as Indicators to Evaluate C3 and C4 Turfgrass under Different Water Conditions

José Marín,Jaime Lloret,Lorena Parra,Alberto Masaguer,Pedro V Mauri,Salima Yousfi

doi:10.3390/su12062160

Abstract

Grasslands have a natural capacity to decrease air pollution and a positive impact on human life. However, their maintenance requires adequate irrigation, which is difficult to apply in many regions where drought and high temperatures are frequent. Therefore, the selection of grass species more tolerant to a lack of irrigation is a fundamental criterion for green space planification. This study compared responses to deficit irrigation of different turfgrass mixtures: a C4 turfgrass mixture, Cynodon dactylon-Brachypodium distachyon (A), a C4 turfgrass mixture, Buchloe dactyloides-Brachypodium distachyon (B), and a standard C3 mixture formed by Lolium perenne-Festuca arundinacea-Poa pratensis (C). Three different irrigation regimes were assayed, full irrigated to 100% (FI-100), deficit irrigated to 75% (DI-75), and deficit irrigated to 50% (DI-50) of container capacity. Biomass, normalized difference vegetation index (NDVI), green area (GA), and greener area (GGA) vegetation indices were measured. Irrigation significantly affected the NDVI, biomass, GA, and GGA. The most severe condition in terms of decreasing biomass and vegetation indices was DI-50. Both mixtures (A) and (B) exhibited higher biomass, NDVI, GA, and GGA than the standard under deficit irrigation. This study highlights the superiority of (A) mixture under deficit irrigation, which showed similar values of biomass and vegetation indices under full irrigated and deficit irrigated (DI-75) container capacities.

Highlights

In recent decades, the development of big cities and industry have provoked an increase in environmental pollution and poor air quality
The most severe irrigation conditions in term of decreasing biomass were deficit irrigated to 50% of container capacity (DI-50)
The most severe deficit irrigation in terms of decreasing vegetation indices was deficit irrigated to 50% of container capacity (DI-50)

Summary

Introduction

The development of big cities and industry have provoked an increase in environmental pollution and poor air quality. This situation is likely to increase in the future because climatic change is expected to decrease precipitation and increase the emission of pollutant gases. Urban green spaces have been defined as a key ingredient for city sustainability [1]. It has been reported that the provision of urban green space and its associated benefits are important for sustainable urban development from ecological, economic, and social perspectives [2]. The quality of urban green spaces could be at risk with reduced rainfall as well as greater frequency and duration of droughts [4]

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