Nitrogen Fertilizer Rate Effects on Soil Organic Carbon in Iowa Continuous Corn and Corn-Soybean Systems
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The Department of Agronomy seeks to teach the study of the farm-field, its crops, and its science and management. It originally consisted of three sub-departments to do this: Soils, Farm-Crops, and Agricultural Engineering (which became its own department in 1907). Today, the department teaches crop sciences and breeding, soil sciences, meteorology, agroecology, and biotechnology.
History
The Department of Agronomy was formed in 1902. From 1917 to 1935 it was known as the Department of Farm Crops and Soils.
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1902–present
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- Department of Farm Crops and Soils (1917–1935)
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- College of Agriculture and Life Sciences (parent college)
Since 1905, the Department of Agricultural Engineering, now the Department of Agricultural and Biosystems Engineering (ABE), has been a leader in providing engineering solutions to agricultural problems in the United States and the world. The department’s original mission was to mechanize agriculture. That mission has evolved to encompass a global view of the entire food production system–the wise management of natural resources in the production, processing, storage, handling, and use of food fiber and other biological products.
History
In 1905 Agricultural Engineering was recognized as a subdivision of the Department of Agronomy, and in 1907 it was recognized as a unique department. It was renamed the Department of Agricultural and Biosystems Engineering in 1990. The department merged with the Department of Industrial Education and Technology in 2004.
Dates of Existence
1905–present
Historical Names
- Department of Agricultural Engineering (1907–1990)
Related Units
- College of Agriculture and Life Sciences (parent college)
- College of Engineering (parent college)
- Department of Industrial Education and Technology, (merged, 2004)
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Abstract
Nitrogen fertilizer rate is a key factor affecting soil organic C (SOC) in corn-based cropping systems. The objective of this study was to determine the change in SOC in response to long-term N rates for continuous corn and corn-soybean cropping systems at two sites in Iowa. Soil samples were collected to a depth of 15 cm in 1999 and again in 2014 after 15 years of corn N rate treatments ranging from 0 to 269 kg ha-1. The soil samples were analyzed for total C and N concentrations. For continuous corn at both sites, the average annual change in SOC increased significantly from below 0 Mg ha-1 yr-1 where no N was applied, to an optimum of approximately 0.13 Mg ha-1 yr-1 at N rates between 150 and 200 kg ha-1. For corn-soybean rotations, the average annual change in SOC was generally below 0 Mg ha-1 yr-1 and increased slightly, but not significantly, with increasing N rate. The results indicate that adequately fertilized continuous corn systems have the potential to accrue more SOC than corn-soybean rotations.
Comments
This is a poster from the ASA-CSSA-SSSA Annual Meeting, Minneapolis, MN. 15-18 Nov. 2015. Posted with permission.