Impacts of management practices on bioenergy feedstock yield and economic feasibility on Conservation Reserve Program grasslands

Abstract

Perennial grass mixtures planted on Conservation Reserve Program (CRP) land are a potential source of dedicated bioenergy feedstock. Long-term nitrogen (N) and harvest management are critical factors for maximizing biomass yield while maintaining the longevity of grass stands. A six-year farm-scale study was conducted to understand the impact of weather variability on biomass yield, determine optimal N fertilization and harvest timing management practices for sustainable biomass production, and estimate economic viability at six CRP sites in the United States. Precipitation during the growing season was a critical factor for annual biomass production across all regions, and annual biomass production was severely reduced when growing season precipitation was below 50% of average. The N rate of 112 kg ha À1 produced the highest biomass yield at each location. Harvest timing resulting in the highest biomass yield was site-specific and was a factor of predominant grass type, seasonal precipitation, and the number of harvests taken per year. The use of N fertilizer for yield enhancement unambiguously increased the cost of biomass regardless of the harvest timing for all six sites. The breakeven price of biomass at the farmgate ranged from $37 to $311 Mg À1 depending on the rate of N application, timing of harvesting, and location when foregone opportunity costs were not considered. Breakeven prices ranged from $69 to $526 Mg À1 when the loss of CRP land rental payments was included as an opportunity cost.Annual cost of the CRP to the federal government could be reduced by over 8% in the states included in this study; however, this would require the biomass price to be much higher than in the case where the landowner receives the CRP land rent. This field research demonstrated the importance of long-term, farm-scale research for accurate estimation of biomass feedstock production and economic viability from perennial grasslands.

Biomass production of herbaceous energy crops in the United States: field trial results and yield potential maps from the multiyear regional feedstock partnership

“…Conservation Reserve Program lands may represent an important resource for producing cellulosic bioenergy feedstock without competing for land with food, feed, and fiber production. Our long‐term field study during 2008–2013 indicates that the annual biomass yield was 2.82 Mg ha −1 for warm‐season mixture CRP land and 5.10 Mg ha −1 for cool‐season mixture CRP land under best management practices (Anderson et al ., ). Nitrogen fertilization is the key agronomic management factor determining biomass yield on CRP land, but applications of 112 kg N ha −1 are probably not the best economic practice with such low biomass production.…”

“…Nitrogen fertilization is the key agronomic management factor determining biomass yield on CRP land, but applications of 112 kg N ha −1 are probably not the best economic practice with such low biomass production. Therefore, it is very important to conduct economic analyses based on rental payments, input costs including fertilizer, biomass yield, and price received for biomass (Anderson et al ., ).…”

“…A 6‐year field study (2008–2013) was conducted through the Feedstock Partnership on established CRP lands at six sites that represented CRP grassland distribution in the United States (Lee et al ., ; Anderson et al ., ). Three of the sites—Ellis County, KS, Jackson County, OK, and Foster County, ND—were planted to predominantly warm‐season grass mixtures, and the other three sites—Judith Basin County, MT, Oconee County, GA, and Boone County, MO—to cool‐season grass mixtures.…”

Effects of nitrogen fertilization and bioenergy crop type on topsoil organic carbon and total Nitrogen contents in middle Tennessee USA

“…However, we found that N fertilization significantly increased SOC and TN in both SG and GG croplands. This was likely due to the minimal management and mechanical disturbance in our plots, which minimized soil decomposition due to less exposure of below surface soil to air, consequently diminished soil C and N losses in favor of soil C and N accumulations in perennial bioenergy feedstock grasslands [56][57][58]. In Table 1.…”

Adopting bioenergy crops: Does farmers’ attitude toward loss matter?

“…We refer readers to Anderson et al. () for a study regarding using CRP land as a potential source of biomass production.…”