Comparative Nutrient Use Efficiency by Candidate Biofuel Crops

This report focuses on efforts at the Throckmorton Purdue Agricultural Center, where the objective is to determine how variation in soil test P and K impacts biomass yield, tissue P and K concentrations, and biomass composition (neutral detergent fiber, acid detergent fiber, lignin, sugars, starch) of switchgrass. This research has taken on additional importance because engineers have recently revealed that efficiency of conversion of plant biomass to liquid fuels using pyrolysis is markedly reduced with K in biomass. Briefly stated, high biomass yield with minimal tissue K will be one of several key factors determining system efficacy.

Plots were established in 2007 on a site where a previous alfalfa nutrition study created a wide range in soil test P and K. Biomass yields have been obtained in 2008, 2009, and 2010. Biomass sample analyses for all years have been completed. Soil samples (0 to 10 and 10 to 20 cm) have been obtained and P and K analyses completed. Analysis of variance and regression are being used to determine the relationships among soil and tissue P and K levels and biomass yield and composition. Mr. Patrick Woodson joined the research effort in the summer of 2010 and will complete the analysis of these data for his M.Sc. degree. IN-25F