Integrated crop-livestock effects on soil carbon and nitrogen in a semiarid region

Authors: Liebig, Mark; FAUST, DEREK - Clover Park Technical College; Archer, David; Kronberg, Scott; Hendrickson, John; TANAKA, DONALD - North Dakota State University

Submitted to: Agrosystems, Geosciences & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/2/2020
Publication Date: 9/17/2020
Citation: Liebig, M.A., Faust, D., Archer, D.W., Kronberg, S.L., Hendrickson, J.R., Tanaka, D. 2020. Integrated crop-livestock effects on soil carbon and nitrogen in a semiarid region. Agrosystems, Geosciences & Environment. https://doi.org/10.1002/agg2.20098.
DOI: https://doi.org/10.1002/agg2.20098

Interpretive Summary: Integrated crop-livestock (ICL) systems have the potential to balance production and environmental goals by improving soil conditions. Among the suite of soil properties frequently measured in agricultural production systems, soil organic carbon (SOC) and total nitrogen (TN) are ‘keystone’ indicators, as their status provides insight into a soil’s capacity to efficiently cycle nutrients, retain water, and support soil biota. However, few studies have evaluated ICL system effects on SOC and TN in semiarid regions, where changes in soil properties occur slowly. Therefore, ICL system effects on SOC and TN were determined in a long-term experiment near Mandan, North Dakota, USA. Study results found ICL treatments with residue mechanically removed contributed to lower SOC and TN compared to treatments where residue was grazed or left in place. Similarly, SOC increased over time in treatments where residue was grazed or retained. Outcomes highlighted the importance of residue retention and livestock grazing for increasing SOC and TN in ICL systems under semiarid conditions.

Technical Abstract: Integrated crop-livestock (ICL) system effects on soil organic carbon (SOC) and total nitrogen (TN) are highly variable due to differences in ecoregion-specific management practices, historical land use, and inherent climatic/edaphic attributes. Few studies have evaluated ICL system effects on SOC and TN in semiarid regions, where slow change in soil attributes require a commitment to long-term research. This study quantified ICL system effects on SOC and TN in a long-term experiment near Mandan, North Dakota, USA. Effects of three residue management treatments (GRAZED, REMOVED, CONTROL) on SOC and TN were determined for five depth increments (0-0.08, 0.08-0.15, 0.15-0.31, 0.31-0.61, and 0.61-0.91 m) and associated equivalent soil masses in 1999 and 2014. No-till practices were employed for the duration of the study following conversion of perennial grass pastures. Residue management affected SOC and TN in near-surface depths only, with greater concentration of SOC and TN at 0-0.08 m under GRAZED compared to REMOVED in 2014 (P=0.0844 and 0.0576). When expressed on an equivalent mass basis, SOC stocks were greater under GRAZED and CONTROL compared to REMOVED. Soil organic C and TN stocks increased over time in the CONTROL by 11.2 Mg C ha-1 and 1.2 Mg N ha-1, respectively (P=0.0728 and 0.0868). Soil organic C stocks also increased over time under the GRAZED treatment by 10 Mg C ha-1 (P=0.0630). Study results highlighted the importance of residue retention and livestock grazing for increasing SOC and TN in ICL systems under semiarid conditions.