Crop residue removal from corn, wheat and grain sorghum can adversely impact soil and environmental quality, a new study suggests.
Removal of more than 50 percent of crop residue can have negative consequences for soil structure, reduce soil organic carbon sequestration, increase water erosion, and reduce nutrient cycling and crop production, particularly in erodible and sloping soils, according to the study published in the March-April issue of Agronomy Journal.
Crop residues, perennial warm season grasses, and short- rotation woody crops are potential biomass sources for cellulosic ethanol production.
While most research is focused on the conversion of cellulosic feedstocks into ethanol and increasing production of biomass, the impacts of growing energy crops and the removal of crop residue on soil and environmental quality have received less attention, said the study conducted by researchers at the American Society of Agronomy.
Moreover, effects of crop residue removal on soil and environmental quality have not been compared against those of dedicated energy crops, the study noted.
Residue removal at rates of less than 25 percent can cause loss of sediment in runoff relative to soils without residue removal. To avoid the negative impacts on soil, perhaps only a small fraction of residue might be available for removal. This small amount of crop residue is not economically feasible nor logistically possible, according to the study.
"Crop residue removal can make no-till soils a source rather than a sink of atmospheric carbon" even at rates lower than 50 percent, said lead researcher Humberto Blanco.
Blanco recommended developing other alternative biomass feedstock sources for cellulosic ethanol production.
An alternative to crop residue removal is growing warm season grasses and short-rotation woody crops as dedicated energy crops, according to the study.
The study drew the conclusion after reviewing the impacts of crop residue removal, warm season grasses, and short-rotation woody crops on critical soil properties, carbon sequestration, and water quality as well as the performance of energy crops in marginal lands.
Source: Xinhua
