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ARS Home » Plains Area » Lincoln, Nebraska » Agroecosystem Management Research » Research » Publications at this Location » Publication #372526
Research Project: Evaluating Management Strategies to Increase Agroecosystem Productivity, Resilience, and Viability

Location: Agroecosystem Management Research

Title: Long-term rotation diversity and nitrogen effects on soil organic carbon and nitrogen stocks

Author
item Schmer, Marty
item Jin, Virginia
item Wienhold, Brian
item BECKER, SOPHIA - Wheaton College
item VARVEL, GARY - Retired ARS Employee

Submitted to: Agrosystems, Geosciences & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/16/2020
Publication Date: 6/2/2020
Citation: Schmer, M.R., Jin, V.L., Wienhold, B.J., Becker, S.M., Varvel, G.E. 2020. Long-term rotation diversity and nitrogen effects on soil organic carbon and nitrogen stocks. Agrosystems, Geosciences & Environment. 3(1):e20055. https://doi.org/10.1002/agg2.20055.
DOI: https://doi.org/10.1002/agg2.20055

Interpretive Summary: Long-term effects from crop rotation and soil management practices on soil organic carbon and soil nitrogen stocks provides important information on sustainable cropland management under a changing climate. Quantifying soil organic carbon storage both by soil layer and cumulatively is important in detecting the influence of management on soil organic carbon changes. We investigated how fertilizer rate and crop rotations impact soil organic carbon from a 34-year study located in eastern Nebraska. Seven crop rotations (three continuous cropping systems; two 2-yr crop rotations; and two 4-yr crop rotations) and three N-levels were compared. We took soil samples to a depth of 150 cm or 5 feet. Differences were found in the surface soils (0 to 7.5 cm) with greater soil organic carbon in the rotations with more than one crop included. Total soil N was greater with increased crop rotation diversity for the 0-30 cm soil profile. Long-term N fertilization levels did not impact SOC stocks for cumulative soil depths. At the 0 to 150 cm soil depth, SOC stocks were similar between N levels and greater for the 4-yr versus 2-yr crop rotations.

Technical Abstract: Understanding the impacts of long-term fertilizer management and rotation diversity on soil carbon and nitrogen (N) is needed under a changing climate. The objective of this study was to evaluate the effects of N fertilizer level and crop rotation diversity on soil organic carbon (SOC) and soil N stocks from a 34-yr study located in eastern Nebraska. Seven crop rotations (three continuous cropping systems; two 2-yr crop rotations; and two 4-yr crop rotations) and three N levels were compared. Soil samples were taken to a depth of 150 cm. Differences in SOC stocks were largely confined to the 0 to 7.5 cm depth, with greater SOC (P = 0.0002) in rotations than continuous cropping systems and greater SOC (P = 0.0004) in 4-yr versus 2-yr rotations. Total soil N was greater with increased crop rotation diversity for the 0-30 cm soil profile. Greater SOC levels occurred with N fertilization for the 0 to 7.5 cm depth. At the 0 to 150 cm soil depth, SOC stocks were similar between N levels and greater for the 4-yr versus 2-yr crop rotations (P = 0.0492). Trends in total N stocks were similar to those of SOC stocks. Overall, crop rotation had a larger effect on SOC and N stocks than N fertilizer.