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Fluid Journal : Fluid Journal 1996-1998
3 Fluid Journal Spring 1998 human activities. benefit from such research. Table 4 shows a current estimate of CO2,of U.S. cropland. The 1,676 million-metric-ton/year estimate is probably low because many crops have not been studied to determine the amount of residue from roots and tops. All of these crops should respond positively to research to increase yields. In addition to the 300+ million acres of cropland, there are about 700 million acres of forests. Some of these forest acres could be intensively managed to assimilate more tons of CO2,. Fertilizing with the proper nutrients could increase new growth and fix more C02, as well as produce more desirable timber. Finally, let's not overlook the 600 million acres of grassland. A project to avoid the inanity of emission cutbacks would require a long-term goal--- possibly 20 to 30 years. Remember, in the case of corn it took almost 40 years to come from 55 to 126 bu/A. I believe it is entirely feasible to set an average yield goal of 275 bu/A, matching Herman Warsaw's 10-year average. In 1997, Francis Childs, an Iowa corn farmer, averaged 280 bu/A! Organic matter fragile As seen, crops can absorb tremendous amounts of CO2,. Carbon is fixed in harvested crops, and in residue/ roots left in fields. Fate of this carbon in harvested crops is difficult to quantify, but certainly much of it ends up as sewage or meat. The remainder is released as CO2 by respiration. Carbon in residue and roots is converted to organic matter under favorable conditions. Research is finding ways to increase the conversion percentage, primarily with new tillage methods and by adequate nutrition to aid microbial processes. New tillage methods also can prevent losses of organic mattdr once it is formed. Stashing carbon is not a problem unique to agriculture. Forests are believed to absorb CO2,and store it permanently. We know trees live, die, decay, and release CO2,in the process. Long-term, food crops can store tremendous quantities of CO2, in organic matter. However, it is true that after 20 years or so the soil will reach an equilibrium when no more carbon can be stored. Environmentally beneficial In conclusion, high-yield research could produce significant dividends that would substantially benefit the environment, the family dinner table, and, yes, even American agriculture. Projecting an average U.S. corn yield of 275 bu/A in the future would mean assimilation by the crop of 1,778 million metric tons of CO2,! Soil fertility would be improved! Soil erosion would be checked, as well as nutrient leaching by improving residue management! More food would be available to meet the demands of an increasing global population! Finally, higher yields would mean higher profits for agriculture! Lohry is chairman of Nutra-Flo Company in Sioux City, IA.
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