MAES Research Shows Cover Crops, Composting Offset Carbon Loss From Corn Stover Ethanol Production

posted on December 23, 2008 5:52am


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EAST LANSING, Mich.—Cellulosic-based ethanol has emerged as one
of the most commercially viable technologies as the United States
continues to develop alternative energy methods and push toward energy
independence. Corn stover, the leaves and stalks of corn plants left in
the field after harvest, remains the most popular source available, but
the loss of soil organic carbon (SOC) associated with its removal for
use as a cellulosic ethanol feedstock is of agricultural and
environmental concern.


  To address this issue, Michigan Agricultural Experiment Station (MAES)
crop and soil scientists Kurt Thelen and Doo-Hong Min and graduate
student Bradley Fronning teamed up to study the effectiveness of
certain farming practices such as the integration of cover crops,
manure and compost to reduce carbon loss in fields where corn stover is


  The team measured soil carbon changes as well as nitrous oxide and
methane gas emissions from corn stover ethanol field plots managed
under various carbon augmentation practices. Estimates of the
manufacturing carbon cost of crop inputs, methane emissions from a
livestock manure source, methane and nitrous oxides generated during
manure storage and application, and fuel usage in crop production were
also assessed.


  Study results showed that corn stover-based bioenergy cropping systems
can be managed to increase short-term carbon storage rates in soils
and reduce overall net global warming potential by using no-till
planting methods and a manure-based nutrient management system.


  “These results demonstrate that bioenergy cropping systems,
particularly those integrating livestock manure into their management
scheme, are a win-win option on both alternative energy and
environmental fronts,” Thelen said. “Under proper management, livestock
manure can replace carbon lost from corn stover removal and actually
provide an environmental benefit, both in terms of greenhouse gas
mitigation and the improved soil properties associated with increasing
SOC levels, such as increased water retention.”


  Research continues at MSU to evaluate the environmental, agronomic and economic sustainability of bioenergy cropping systems.


  “It will be important to build on this research by comparing tillage
systems –  no-till ersus conventional tillage—and looking at
integrated cropping systems such as corn-alfalfa rotations, which, in
addition to their carbon storage and bioenergy value, are very
important crops as feed sources for the dairy industry,” Min said.


  Support for this work was provided by the MAES, the U.S. Department
of Agriculture Cooperative State Research, Education and Extension
Service, and The Consortium for Agricultural Soils Mitigation of
Greenhouse Gases program.


  The study, “Use of Manure, Compost and Cover Crops to Supplant Crop
Residue Carbon in Corn Stover Removed Cropping Systems,” was recently
published in the Agronomy Journal (Volume 100, pages 1703-1710), and is
available online at:



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