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United States Department of Agriculture

Agricultural Research Service

Research Project: DEVELOP AND IMPROVE STRATEGIES FOR MANAGEMENT OF IRRIGATED AGRICULTURAL CROPS AND SOILS

Location: Northwest Irrigation and Soils Research

Title: Copper Impacts on Corn, Soil Extractability, and the Soil Bacterial Community

Authors
item Ippolito, James
item Ducey, Thomas
item Tarkalson, David

Submitted to: Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 21, 2010
Publication Date: December 10, 2010
Citation: Ippolito, J.A., Ducey, T.F., Tarkalson, D.D. 2010. Copper Impacts on Corn, Soil Extractability, and the Soil Bacterial Community. Soil Science. Vol. 175(12)586-892. http://journals.lww.com/soilsci/pages/currenttoc.aspx

Interpretive Summary: Dairies utilize copper sulfate foot baths to control hoof infections, with copper accumulation in agricultural soils realized when spent foot baths are disposed of in waste lagoons and subsequently utilized for irrigation. We investigated the effect of increasing copper applications to two soils on corn yield and copper concentration, soil total and plant-available copper, and soil microbial community diversity. Copper application up to 250 mg/kg did not affect corn yield, but yield was reduced by up to 80% at greater copper application rates. As copper concentrations increased microbial diversity decreased. To prevent excessive corn copper accumulation and negative impacts on the soil microbial community, it is recommended available soil copper not to exceed 130 mg/kg in agroecosystems associated with the two soils utilized.

Technical Abstract: Dairies utilize copper sulfate foot baths to control hoof infections, with copper accumulation in agricultural soils realized when spent foot baths are disposed of in waste lagoons and subsequently utilized for irrigation. We investigated the effect of increasing copper applications (up to 1000 mg/kg) to two soils (Declo: coarse-loamy, mixed, superactive, mesic Xeric Haplocalcid; Logan: fine-silty, mixed, superactive, mesic Typic Calciaquoll) on corn (Zea mays L.) yield and copper concentration, soil total and plant-available copper, and the soil microbial community diversity using Ribosomal intergenic spacer analysis (RISA) followed by cluster analysis. In both soils, copper application up to 250 mg/kg did not affect corn yield; at 500 mg copper per kg corn yield was reduced by up to 80%. The 250 and 500 mg/kg copper application rates increased corn copper content grown in Declo soil; only the 500 mg/kg copper application rate caused an increase in corn copper content grown in the Logan soil. Soil total and plant-available copper content increased with increasing copper application rate, with 60 to 75% of the added copper still plant-available at the end of the study regardless of initial application rate. Comparing plant-available copper to corn copper concentrations for the Declo soil, 130 and 215 mg/kg of plant-available soil copper would be detrimental in terms of sheep and cattle dietary copper intake; 220 and 300 mg/kg of plant-available soil copper would be detrimental for both animal species in Logan soil. In both soil series, as copper concentrations increased the similarity amongst RISA profiles decreased, with clustering patterns indicative of changes within the overall microbial community. As copper concentrations increased microbial diversity decreased and species evenness remained high suggesting that few phylotypes predominated within the RISA profiles. To prevent excessive corn copper accumulation and negative impacts on the soil microbial community, it is recommended available soil copper not to exceed 130 mg/kg in agroecosystems associated with the Logan or Declo soil series.

Last Modified: 10/1/2014
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