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Browsing Faculty Publications by Subject "agricultural productivity"
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Item Open Access Managing soil carbon and nitrogen for productivity and environmental quality(Colorado State University. Libraries, 2004-05) Robertson, G. Philip, author; Knezek, Bernard D., author; Paul, Eldor A., author; Parker, Elaine, author; Smeenk, Jeffrey, author; Kizilkaya, Kadir, author; Willson, Thomas C., author; Harwood, Richard R., author; Jose E., Sanchez, author; American Society of Agronomy, publisherIn this study, we investigated the impact of cropping system management on C and N pools, crop yield, and N leaching in a long-term agronomic experiment in Southwest Michigan. Four management types, conventional (CO), integrated fertilizer (IF), integrated compost (IC), and transitional organic (TO) were applied to two crop sequences, a corn (Zea mays L.)–corn–soybean [Glycine max (L.) Merr.]–wheat (Triticum aestivum L.) rotation and continuous corn, which were grown with and without cover crops in the IF, IC, and TO managements. Using compost as a fertility source and reducing the use of herbicides and other chemicals resulted in long-term changes in soil organic matter pools such TO ≥ IC > IF ≥ CO for total C and N and for the labile C and N measured through aerobic incubations at 70 and 150 d. Mineralizable N varied within the rotation, tending to increase after soybean and decrease after corn production in all systems. Corn yield was closely associated with 70-d N mineralization potential, being greatest for first-year corn with cover and least for continuous corn without cover under all management types. Although the TO and IC systems produced the lowest yield for second-year or continuous corn, the combination of soybean and wheat plus red clover (Trifolium pratense L.) always supported high yield for first-year corn. Fall nitrate level and nitrate leaching were higher for commercially fertilized corn than for any other crop or for compost-amended corn.