A Review of Modeled Water Use Efficiency of Highly Productive Perennial Grasses Useful for Bioenergy

James R Kiniry,Sumin Kim

doi:10.3390/agronomy10030328

Abstract

Whole plant productivity is obviously the ultimate product of leaf photosynthesis and this has led to numerous efforts to relate the two. However, often with perennial grasses, plant productivity is more sink-limited than source-limited, causing the linkage between the photosynthetic rate and productivity to be weak or nonexistent. This has led to a different approach, characterizing plant productivity in terms of the efficiency of intercepted light use in producing biomass, also called radiation use efficiency. Likewise, the efficiency of the use of water to produce plant biomass, or water use efficiency, has been the object of much interest. The use of a simulation model to quantify biomass, using radiation use efficiency in parallel with a daily water balance simulation, allows for the effective calculation of water use efficiency. In this project, the process of determining radiation use efficiency with field data is described, as well as example values for highly productive perennial grasses useful for feedstock for bioenergy. In addition, values of water use efficiency for these grasses are reported and compared with other perennial grasses and common cultivated crops.

Highlights

High-yielding perennial grasses, such as switchgrass (Panicum virgatum L.) and giant miscanthus (Miscanthus × giganteus), have been promoted as promising second-generation biofuel feedstocks in the U.S and elsewhere
We report water use efficiency (WUE) as the plant dry weight increase divided by the amount of water transpired
Values for perennial grasses range from 0.4 g per MJ for prairie sandreed (Calamovilfa longifolia (Hook.) Scribn.) in Montana [22] to 4.4 g per MJ for Alamo switchgrass in Texas [28]

Summary

Introduction

High-yielding perennial grasses, such as switchgrass (Panicum virgatum L.) and giant miscanthus (Miscanthus × giganteus), have been promoted as promising second-generation biofuel feedstocks in the U.S and elsewhere. Their ability to produce large fuel loads on marginal sites that are not ideal for row crops with minimal inputs of fertilizer has pushed them to the forefront of bioenergy discussions. These models all have a similar basic functionality All these models simulate the interception of light by the leaf canopy and the conversion of light into biomass. They all partition biomass into the various plant components. These models simulate drought stress and its impacts on plant growth

Methods

Results

Conclusion