TY - JOUR
T1 - Nitrogen and harvest management effects on switchgrass and mixed perennial biomass production
AU - Sawyer, Anne
AU - Rosen, Carl
AU - Lamb, John
AU - Sheaffer, Craig
N1 - Publisher Copyright:
© 2018 by the American Society of Agronomy.
PY - 2018/7/1
Y1 - 2018/7/1
N2 - Biofuel production using native perennials on marginal soils can reduce US dependence on foreign oil and curtail greenhouse gas emissions with minimal impact on food crop production. We quantified post-establishment biomass yield and N removal as a function of harvest regime (anthesis and post-frost) and N application rate (0, 56, and 112 kg N ha–1) at two marginal sites in Minnesota. We examined three switchgrass (Panicum virgatum L.) monocultures: ‘Shawnee’, ‘Sunburst’, and ‘Liberty’, a new bioenergy variety, and three polycultures: grass-only, grass-legume, and grass-legume-forb. On an excessively-drained loamy sand soil, maximum productivity occurred in ‘Sunburst’ and ‘Shawnee’ switchgrass fertilized at 112 kg N ha–1 yr–1 in the post-frost harvest regime, with 3-yr total yields of 11.0 Mg ha–1, while ‘Liberty’ produced 7.0 Mg ha–1. On an eroded loam soil, maximum post-frost productivity in ‘Shawnee’, ‘Sunburst’, and ‘Liberty’ was similar at 56 and 112 kg N ha–1 yr–1, with total yields of 32.6, 29.8, and 23.5 Mg ha–1, respectively. Yields of the low-diversity (LD) grass mix were similar to ‘Shawnee’ switchgrass at both locations, indicating that an LD grass mix or well-adapted switchgrass monoculture are likely the most productive feedstocks for this region. Most feedstocks produced similar or greater yields and removed less N in the post-frost relative to the anthesis harvest. While producers may have flexibility in harvest timing for some feedstocks in the first few years following establishment, a post-frost harvest regime may promote stand longevity with less N fertilizer use over time.
AB - Biofuel production using native perennials on marginal soils can reduce US dependence on foreign oil and curtail greenhouse gas emissions with minimal impact on food crop production. We quantified post-establishment biomass yield and N removal as a function of harvest regime (anthesis and post-frost) and N application rate (0, 56, and 112 kg N ha–1) at two marginal sites in Minnesota. We examined three switchgrass (Panicum virgatum L.) monocultures: ‘Shawnee’, ‘Sunburst’, and ‘Liberty’, a new bioenergy variety, and three polycultures: grass-only, grass-legume, and grass-legume-forb. On an excessively-drained loamy sand soil, maximum productivity occurred in ‘Sunburst’ and ‘Shawnee’ switchgrass fertilized at 112 kg N ha–1 yr–1 in the post-frost harvest regime, with 3-yr total yields of 11.0 Mg ha–1, while ‘Liberty’ produced 7.0 Mg ha–1. On an eroded loam soil, maximum post-frost productivity in ‘Shawnee’, ‘Sunburst’, and ‘Liberty’ was similar at 56 and 112 kg N ha–1 yr–1, with total yields of 32.6, 29.8, and 23.5 Mg ha–1, respectively. Yields of the low-diversity (LD) grass mix were similar to ‘Shawnee’ switchgrass at both locations, indicating that an LD grass mix or well-adapted switchgrass monoculture are likely the most productive feedstocks for this region. Most feedstocks produced similar or greater yields and removed less N in the post-frost relative to the anthesis harvest. While producers may have flexibility in harvest timing for some feedstocks in the first few years following establishment, a post-frost harvest regime may promote stand longevity with less N fertilizer use over time.
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U2 - 10.2134/agronj2017.11.0657
DO - 10.2134/agronj2017.11.0657
M3 - Article
AN - SCOPUS:85050163545
SN - 0002-1962
VL - 110
SP - 1260
EP - 1273
JO - Agronomy Journal
JF - Agronomy Journal
IS - 4
ER -