Manure and residue inputs maintained soil organic carbon in Upper Midwest conservation production systems

Authors: Weyers, Sharon; Johnson, Jane; Archer, David; Forcella, Frank; Gesch, Russell - Russ

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/6/2018
Publication Date: 8/2/2018
Citation: Weyers, S.L., Johnson, J.M., Archer, D.W., Forcella, F., Gesch, R.W. 2018. Manure and residue inputs maintained soil organic carbon in Upper Midwest conservation production systems. Soil Science Society of America Journal. 82:878-888. https://doi.org/10.2136/sssaj2017.09.0344.
DOI: https://doi.org/10.2136/sssaj2017.09.0344

Interpretive Summary: Conservation production systems are needed in the upper Midwest to slow down soil and nutrient loss through tillage-induced erosion. However, due to the cool, wet climate, producers are reluctant to adapt no-till strategies. Researchers at the North Central Soil Conservation Research Lab in Morris, MN, and the Northern Great Plains Research Laboratory in Mandan, ND, evaluated strip-tillage (ST) and a diverse four-year crop rotation (4y) as alternatives to no-till strategies. Change in soil organic carbon (SOC) was used as an indicator. Manure application, under an organic management strategy, was best at preventing loss of SOC. Residue inputs were also important for reducing SOC loss. These results will help researchers, land managers and policy makers to develop, support and promote management strategies that target increased residue production through either improved yields or inputs from sources such as manure and cover crops.

Technical Abstract: Conservation production systems are needed in the upper Midwest to slow down soil and nutrient loss through tillage-induced erosion. However, due to the cool, wet climate, producers are reluctant to adapt no-till strategies. With focus on strip-tillage (ST) and a diverse four-year crop rotation (4y) as alternatives to no-till, we assessed eight integrated strategies under both conventional (CNV) and organic (ORG) management. Strategies assessed included conventional moldboard plow + disk tillage (CT), with (YF) fertilizer or manure, with no (NF) amendments, and two-year (2y) rotations: ST-YF-4y, ST-NF-4y, ST-YF-2y, ST-NF-2y, CT-YF-4y, CT-NF-4y, CT-YF-2y, and CT-NF-2y. Using the equivalent soil mass method, to a 60 cm depth, we measured change over time and rates of loss of total soil organic C and N (SOC and SON). Soil was sampled in the fall, after harvest and before tillage, in the first, second, sixth, and eighth years of rotation between 2002 and 2009. In 2002, management had no effect. From 2003-2009, average SOC and SON were greater under CNV-4y systems than CNV-2y systems, and under YF than NF strategies. Additionally, SON was greater with ST than CT. Averaged across all production systems loss of SOC occurred from 2003 – 2009, but SON did not change. Loss of SOC was not attributable to any individual management strategy. For integrated strategies, SOC was not lost in CNV-ST-YF-2y due to high residue input, nor lost in ORG-ST-YF-4y, ORG-ST-YF-2y, ORG-CT-YF-2y, and ORG-CT-NF-2y, largely due to manure application. In general, lower rates of loss correlated with higher residue inputs.