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United States Department of Agriculture

Agricultural Research Service

2007 Annual Report

1a.Objectives (from AD-416)
Determine relationships between effects of elevated carbon dioxide on gene expression and physiological responses which increase the response of crop yield to atmospheric and climatic global changes. Determine how changes in carbon dioxide concentration affect the relative competitiveness of crops and weeds. Determine how elevated carbon dioxide affects relationships between fertilizer and weed management practices and crop yield and soil carbon sequestration.

1b.Approach (from AD-416)
Crop and weed species will be grown at the current ambient concentration of carbon dioxide and at 1.5 times that concentration in field plots, using open top chambers, and in growth cabinets. Changes in gene expression, physiology, and the growth of crops will examined at ambient and elevated concentrations of carbon dioxide in combination with high temperature stress, drought stress, and competition from weeds. Soybeans, common beans, spring wheat, oats and some weed species will be examined for genotypic differences in responsiveness to carbon dioxide concentration. Invasive and non-invasive weed species will be compared for responses to rising atmospheric carbon dioxide. Impacts of elevated carbon dioxide on yield responses to nitrogen fertilizer will be determined in a corn, wheat, soybean crop rotation system. The effect of elevated carbon dioxide on soil carbon sequestration will be examined in two no-till cropping systems.

"Elevated carbon dioxide reduces the efficacy of weed control by glyphosate in roundup-ready soybeans." Work in the Crop Systems and Global Change Laboratory has shown that application of glyphosate at a rate sufficient to prevent crop yield loss due to weeds at the current carbon dioxide concentration failed to prevent significant loss of yield of soybeans due to weeds at an elevated carbon dioxide. This suggests that the current weed control measures may become less effective as the concentration of carbon dioxide in the atmosphere rises, increasing either the cost of controlling weeds or the losses in crop yield caused by weeds.

This accomplishment aligns with the NP 204 Action Plan, Agricultural Ecosystems Impacts, "Measure and predict plant responses (above and below-ground) to multiple interactions of abiotic and biotic stresses with rising carbon dioxide."

5.Significant Activities that Support Special Target Populations

6.Technology Transfer

Number of non-peer reviewed presentations and proceedings13
Number of newspaper articles and other presentations for non-science audiences12

Review Publications
Bunce, J.A. 2006. How do leaf hydraulics limit stomatal conductance at high water vapour pressure deficits? Plant Cell and Environment. 29:1644-1650.

Bunce, J.A. 2006. Use of a minimally invasive method of measuring leaf stomatal conductance to examine stomatal responses to water vapor pressure difference under field conditions. Agricultural and Forest Meteorology. 139:335-343.

Bunce, J.A. 2007. Direct and Acclimatory Responses of Dark Respiration and Translocation to Temperature. Annals Of Botany. 100:67-73.

Ziska, L.H., George, K., Frenz, D.A. 2007. Establishment and persistence of common ragweed (Ambrosia artemisiifollia L.) in disturbed soil as a function of an urban-rural macro-environment. Global Change Biology. 13:266-274.

Ziska, L.H., Blowsky, R. 2007. A quantitative and qualitative assessment of mungbean (vigna mungo(l.) wilczek) seed in response to elevated atmospheric carbon dioxide: potential changes in fatty acid composition. Journal of Agriculture and Food Chemistry. 87:920-923.

Ziska, L.H., Goins, E.W. 2006. Elevated atmospheric carbon dioxide and weed populations in glyphosate treated soybean. Crop Science. 46:(3)1354-1359.

Ziska, L.H., Sicher Jr, R.C., George, K., Mohan, J.E. 2007. Rising atmospheric carbon dioxide and potential impacts on the growth and toxicity of poison ivy (Toxicodendron radicans). Weed Science. 55(4)288-292.

Ziska, L.H., Runion, G.B. 2007. Future weed, pest and disease problems for plants. Book Chapter. In: Newton, P.C.D., Carran, R.A., Edwards, G.R., Niklaus, P.A., editors. Agroecosystems in a Changing Climate. Boca Raton, FL: CRC Press. p. 261-287.

Last Modified: 4/21/2015
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