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ARS Home » Midwest Area » Morris, Minnesota » Soil Management Research » Research » Publications at this Location » Publication #112189
Title: TILLAGE SYSTEM EFFECTS ON SOIL STRUCTURE IN THE UPPER MISSOURI RIVER BASIN

Author
item SCHUMACHER, T - SOUTH DAKOTA STATE UNIV
item Lindstrom, Michael
item EYNARD, A - SOUTH DAKOTA STATE UNIV
item MALO, D - SOUTH DAKOTA STATE UNIV

Submitted to: International Soil Tillage Research Organization Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 7/7/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: Agricultural fields in the upper Missouri River Basin have been cultivated since settlement in the late nineteenth and early twentieth centuries. A degradation in soil organic carbon content and soil structural properties has taken place during this period due to intensive tillage and mineralization of soil organic carbon to carbon dioxide. No-till crop production may slow or reverse soil carbon loss and structural degradation It was the objective of this study to compare the effects of no-till, conventional-till, and grassland on soil carbon and soil structure. Twelve sites were selected along the Missouri River Basin. At each site, the three management systems were situated in close proximity and matched by soil series and landscape topography. Soil organic carbon, soil aggregate size and stability, and soil structure was determined at all sites for the three management systems. Results show that an improvement in soil organic carbon nand soil structure has taken place with no-till in comparison to conventional-till, but not to the degree found in the grasslands. Soil structural determinations in the no-till and conventional-till management systems showed the presence of a compacted layer from heavy agricultural equipment, which had higher bulk densities than soils in grassland. These data show that soil structural improvements create a more favorable condition for plant production than conventional-till practices, which can be used by conservation planners for development of sustainable crop production systems.

Technical Abstract: Many fields in the Upper Missouri River Basin have been under cultivation since settlement in the late nineteenth and early twentieth centuries. Our objective was to evaluate the effect of management intensity on the structure of prairie soils (3 Haplustolls, 7 Argiustolls, 5 Haplusterts) in central South Dakota. Management systems were grouped in three categories (grassland, no-till, and conventional-till). Twelve locations were selecte as replications along the Missouri River. At each location, soil structure of three management systems with the same soil series was characterized. Four sampling sites were located in each experimental unit. Soil structure was morphologically described in the field. Water aggregate stability of the top 0 - 0.05 m was determined by wet sieving and slaking tests. Wet stability of surface aggregates was similar under grass and no-till and greater than in tilled soils. Soil carbon of the 1-2 mm aggregate fraction and slaking stability increased from conventional-till, to no-till, to grass. Mean weight diameter of aggregates increased from grass, to no-till, to conventional-till. However, the granular structure observed under grass was not observed in no-till or conventional-till. Compacted layers were present in most of the conventional-till and no-till systems, which had higher bulk densities than soils under perennial grasses. Increased crop diversity with introduction of perennial species and careful use of heavy equipment may further improve soil structure in no-till systems, which have already created more favorable conditions for plant production than conventional tillage practices in central South Dakota.