Net primary production in three bioenergy crop systems following land conversion

Abstract

Aims Identifying the amount of production and the partitioning to above-and belowground biomass is generally the first step toward selecting bioenergy systems. There are very few existing studies on the dynamics of production following land conversion. The objectives of this study were to (i) determine the differences in aboveground net primary production (ANPP), belowground net primary production (BNPP), shoot-to-root ratio (S:R) and leaf area index in three bioenergy crop systems and (ii) evaluate the production of these three systems in two different land use conversions. Methods This investigation included biometric analysis of NPP on three agricultural sites converted from conservation reserve program (CRP) management to bioenergy crop production (corn, switchgrass and prairie mix) and three sites converted from traditional agriculture production to bioenergy crop production. Important findings The site converted from conventional agriculture produced smaller ANPP in corn (19.03 ± 1.90 standard error [SE] Mg ha-1 year-1) than the site converted from CRP to corn (24.54 ± 1.43 SE Mg ha-1 year-1). The two land conversions were similar in terms of ANPP for switchgrass (4.88 ± 0.43 SE for CRP and 2.04 ± 0.23 SE Mg ha-1 year-1 for agriculture) and ANPP for prairie mix (4.70 ± 0.50 SE for CRP and 3.38 ± 0.33 SE Mg ha-1 year-1 for agriculture). The BNPP at the end of the growing season in all the bioenergy crop systems was not significantly different (P = 0.75, N = 8).