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Biomass Yield Enhancement Required for a Replacement Switchgrass Variety
Author(s) -
Haankuku Choolwe,
Epplin Francis M.
Publication year - 2015
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj14.0349
Subject(s) - panicum virgatum , yield (engineering) , biomass (ecology) , agronomy , production (economics) , economics , bioenergy , environmental science , biofuel , biology , microbiology and biotechnology , microeconomics , materials science , metallurgy
For perennial grasses such as switchgrass ( Panicum virgatum L.) used to produce biomass for biorefineries, the replacement of an existing stand with a new variety may require the loss of a year of production. If the opportunity cost of production is considered, a new cultivar (challenger) expected to result in only a modest yield increase relative to the existing variety (defender) may fail to achieve the clearly superior criterion required by variety release committees. The objective of the study is to determine the minimum expected yield increase in a new switchgrass variety that is required to economically justify the replacement of the defender. An economic model based on capital budgeting analysis is developed. Sensitivity of the expected yield increment was examined with respect to the discount rate, biomass price, field costs, and planning horizon. Results were obtained for estimated defender yields of 16.25 and 24.0 Mg ha −1 . The required yield increment is inversely related to the length (years) of the planning horizon and to the price of the biomass and is positively related to costs and the discount rate. For the base parameter levels, (a defender yield of 16.25 Mg ha −1 , biomass price of US$53 Mg −1 , discount rate of 5%, and planning horizon of 20 yr), a 15% yield increase of 2.4 Mg ha −1 would be required to justify replacement. Economic assessments are important to both producers and breeders when quantifying yield targets for enhanced cultivars.