Radiation-Use Efficiency, Biomass Accumulation, and Potential Carbon Footprint Reduction of Vetivergrass.

Vetivergrass [Vetiveria zizanioides (L.) Nash] now reclassified as [Chrysopogon zizanioides (L.) Roberty] is a densely tufted perennial grass domesticated in south India. Most cultivars are naturally sterile and do not set seed, nor do they produce stolons or rhizomes. The most grown cultivar ‘Sunshine’ was named after the Vetiver grown by Eugene Le Blanc, at Sunshine, Louisiana, USA.  This cultivar has been grown in Louisiana for well over 100 years and has never shown signs of invasiveness. The tillers are strong and stiff. The leaves are narrow, erect, keeled, and the margins are rough to touch. Its massive fine root system can grow very fast and can reach depths up to 3-5 m in the first year. The deep root system makes the vetivergrass extremely drought tolerant. In the US the grass is adapted to the USDA Plant Hardiness Zones 9 to 11 and will grow over a wide range of marginal conditions. The grass has done well in Florida, Louisiana, and South Texas. Plants heights of 1.5 to 2.0 m and up to 40 Mg ha^-1 of dry cellulosic biomass have been reported in Central Texas under dryland conditions. The grass has the ability to re-grow very quickly after harvest. In addition, vetivergrass is highly resistant to most pests and diseases. It can easily be controlled by glyphosate herbicide or by digging up the crown. Besides the many uses of vetivergrass (erosion control, perfumery etc.), it also has potential as a bioenergy feedstock crop. The high aboveground biomass and deep rooting system offer a huge potential carbon (C) sink for C footprint reduction.  In this study we quantify biomass accumulation and the key components of radiation-use efficiency of vetivergrass: rate of dry matter (DM) accumulation, leaf area index (LAI), fraction of intercepted photosynthetically active radiation (FIPAR), etc.