Crop Residues

Abstract

Crop residues (e.g., corn stover and small grain straw) are sometimes excluded when discussing cellulosic energy crops per se, but because of the vast area upon which they are grown and their current role in the development of cellulosic energy systems, this chapter will review several important attributes of this "herbaceous" feedstock. Crop residues are potential feedstock sources for second-generation biofuel production. These materials, along with dedicated energy crops (e.g., switchgrass [Panicum virgatum L.], Miscanthus [Miscanthus × giganteus]), are considered to have greater potential for biofuel production than current first-generation feedstock (i.e., corn grain) [1][2][3]. Production of ethanol and other fuel sources from these lignocellulosic materials is receiving increased financial support for research and development [4][5][6]. Furthermore, biofuel production from crop residues provides a multipurpose land use opportunity where grain can be harvested to meet food and feed demands, while a sustainable portion of the residues provide a potentially available biofuel feedstock.Corn stover, the aboveground plant material left in fields after grain harvest, was identified as an important biomass source in the Billion-Ton Study (2005 BTS) [7]. The vast area from which this feedstock could potentially be harvested was confirmed by USDA National Agricultural Statistics Service (NASS) data showing that between 2005 and 2011, corn was harvested in the U.S.A. from an average of 32 460 000 ha each year [8]. Wheat straw was the other dominant residue identified in the 2005 BTS, and from 2005 through 2011, wheat was harvested in the U.S.A. from an average of 20 037 000 ha each year. Based on these Cellulosic Energy Cropping Systems, First Edition. Edited by Douglas L. Karlen.

Nitrous oxide emission from agricultural soils: Application of animal manure or biochar? A global meta-analysis

“…Moreover, low animal manure C: N ratio significantly enhanced N 2 O, because animal manure provides a favorable environment for denitrifiers (Flessa and Beese, 1995;Meng et al, 2005). Biochar amendment with higher C: N ratios significantly decreased N 2 O emissions due to microbial N immobilization (Cayuela et al, 2010;Baggs et al, 2010). Consequently, a very less amount of soil N is available for microbial processes for N 2 O emissions.…”

Tree – Open Grassland Structure and Composition Drive Greenhouse Gas Exchange in Holm Oak Meadows of the Iberian Peninsula

“…Moreover, N2O exchange was influenced by the structure and composition of the herbaceous layer, increasing N2O emissions with litter and the presence of legumes in the community ( Table 3). The influence of litter on N2O exchange at field conditions is not well understood, but there are some experiments assessing the effect of cover crops on N2O exchange that may provide some understanding [57][58][59]. For instance, an experimental study by Shaaban et al, (2016) reported increasing N2O emissions with the addition of litter onto soil surface.…”