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ARS Home » Plains Area » Brookings, South Dakota » Integrated Cropping Systems Research » Research » Publications at this Location » Publication #306937
Title: The importance of crop residue on soil aggregation and soil organic matter components

Author
item Osborne, Shannon
item HAMMERBECK, AMBER - South Dakota State University
item SCHUMACHER, TOM - South Dakota State University
item PIKUL, JOSEPH - Retired ARS Employee

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/20/2014
Publication Date: 6/22/2014
Citation: Osborne, S.L., Hammerbeck, A., Schumacher, T.E., Pikul, J.L. 2014. The importance of crop residue on soil aggregation and soil organic matter components. In: Proceedings World Congress on Conservation Agriculture 6th International Meeting, p. 17-18. June 22-25, 2014, Winnipeg Manitoba.

Interpretive Summary: Plant residue is the soil’s main source of organic materials that holds soil particles together into aggregates and increases soil carbon storage. This organic matter supplies plant available nutrients, increases water storage, and reduces soil erosion. A long term experiment was established in Eastern South Dakota in 2000 using no-till soil management within a two-year corn/soybean rotation. The experiment was established to evaluate the impact on soil health of removing crop residue. Within the experiment there were three residue removal levels: low (corn harvested for grain; all residues remain on soil surface), medium (corn harvested for grain; residue raked, baled and removed), and high (above ground corn biomass and grain removed) each with and without cover crops. Soil health was evaluated by measuring soil particulate organic matter, soil organic matter, erodible fraction and dry aggregate size distribution. We found that when residue was removed, as in the high residue removal treatment, soil had smaller aggregates that are highly subject to wind and water erosion. The presence of a cover crop shifted the aggregate distribution toward larger aggregates that indicate improved soil structure. Removal of crop residue from the soil surface had a negative impact on measured soil health properties. The addition of a cover crop helped to reduce this impact as measured through aggregate size distribution, erodible fraction and soil organic matter components.

Technical Abstract: Above- and below-ground plant residues are the soil’s main sources of organic materials that bind soil particles together into aggregates and increase soil carbon storage. Serving to stabilize soil particles, soil organic matter assists in supplying plant available nutrients, increases water holding capacity, and helps reduce soil erosion. A long term experiment was established in Eastern South Dakota in 2000 using no-till soil management within a two-year corn (Zea mays L.)/soybean [Glycine max (L.) Merrill] rotation. The objective of the experiment was to determine the impact of removing crop residue on soil health measurements. The experimental design was a split-plot randomized complete block design with three replications. Whole plot treatments consisted of three residue removal levels; low (corn harvested for grain; all residues remain on soil surface), medium (corn harvested for grain; residue raked, baled and removed), and high (above ground corn biomass and grain removed). Split plot treatments were the presence or absence of a cover crop. Soil health was evaluated by measuring soil particulate organic matter (POM), soil organic matter (SOM), erodible fraction (EF) and dry aggregate size distribution (DASD). Results showed that the distribution of soil aggregates was less favorable when residue was removed without the addition of other sources of organic matter such as cover crops. Additionally, when residue was removed and the soil surface was less protected, there was an increase in the EF. There was a reduction in the EF when cover crops were incorporated into the system. Amounts of SOM, fine particulate organic matter (fPOM) and total particulate organic matter (tPOM) consistently decreased as greater amounts of residue were removed from the soil surface. Removal of crop residue from the soil surface had a negative impact on measured soil health properties. The addition of a cover crop helped to reduce this impact as measured through aggregate size distribution, EF and soil organic matter components.