Growing crops for biofuel and forage while conserving soil and water

Master of ScienceDepartment of AgronomyHumberto BlancoThe use of renewable feedstocks to produce cellulosic ethanol is quickly becoming a reality as facilities to produce cellulosic ethanol are scheduled to open in the upcoming years. Initial feedstocks for these facilities are thought to be crop residues such as corn (Zea mays L.) and wheat (Triticum aestivum L.) residues. However, additional feedstocks, such as perennial warm-season grasses (WSG), maybe needed to meet the demands of these bioenergy facilities. Thus, the development of regional dedicated energy crop systems is a high priority. Our objectives were to: a) assess the impacts of growing WSG on water storage, soil physical and hydraulic properties, soil organic carbon (SOC) dynamics, and water and wind erosion as compared with row crops, b) assess the impacts of growing WSG on biomass and forage production and quality and c) determine the most adaptable WSG species to dryland conditions. A number of dedicated energy crops and their performance across three different moisture regimes in Kansas were studied. Biomass yield, soil physical and hydraulic properties, and soil water and wind erosion parameters were measured between August 2010 and August 2012. Additionally, forage quality under two cutting systems (biofuel and forage) and two harvest heights (0.1 m and 0.2 m) and water infiltration was determined in 2011. Differences in bulk density, water retention, infiltration and SOC were found to be minimal. However, differences in wind and water erosion parameters indicate that WSG can protect soil from erosion. Furthermore, soil water data indicate that WSG are better suited to use early season moisture to accumulate biomass than annual row crops. Yield results indicate that a two cut hay system with a 0.1 m cutting height can produce more biomass compared with a one cut biofuel system. Additionally, the hay system improved forage quality parameters. Data collected from this project provided insights into the viability of growing various dedicated energy crops across the region during the first five years of production

Dedicated bioenergy crop impacts on soil wind erodibility and organic carbon in Kansas

Citation: Evers, Byron J., Humberto Blanco‐Canqui, Scott A. Staggenborg, and John Tatarko. “Dedicated Bioenergy Crop Impacts on Soil Wind Erodibility and Organic Carbon in Kansas.” Agronomy Journal 105, no. 5 (2013): 1271–76. https://doi.org/10.2134/agronj2013.0072.Dedicated bioenergy crops such as perennial warm-season grasses (WSGs) may reduce soil erosion and improve soil properties while providing biomass feedstock for biofuel. We quantified impacts of perennial WSGs and row crops on soil wind erodibility parameters (erodible fraction, geometric mean diameter of dry aggregates, and aggregate stability) and soil organic carbon (SOC) concentration under a dedicated bioenergy crop experiment in eastern Kansas after 4 and 5 yr of management. Soil properties were measured under switchgrass (Panicum virgatum L.), big bluestem (Andropogon gerardii L.), miscanthus (Miscanthus × giganteus), and annual row crops including continuous corn (Zea mays L.), photoperiod sorghum [Sorghum bicolor (L.) Moench.], sweet sorghum, and grain sorghum. Perennial WSGs reduced wind erodible fraction by 1.08 to 1.16 times compared with row crops. The geometric mean diameter of dry aggregates under switchgrass and miscanthus was 2.8 to 4.5 times greater than under row crops. Dry soil aggregate stability under miscanthus and big bluestem was greater than under row crops. After 5 yr, differences in SOC concentration between WSGs and row crops were not statistically significant for the 0- to 15-cm depth. Photoperiod sensitive and sweet sorghum had greater biomass yield than WSGs. In 2011, miscanthus yielded more biomass than corn by 5.3 Mg haˉ¹. Overall, growing dedicated bioenergy crops can reduce the soil’s susceptibility to wind erosion but may not significantly increase SOC concentration in this region in the short term