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Repeated Freeze-Thaw Cycle Effects on Soil Compaction in a Clay Loam in Northeastern Montana

Jabro, J. D., Iversen, W. M., Evans, R. G., Allen, B. L., Stevens, W. B.
Soil Science Society of America journal 2014 v.78 no.3 pp. 737
clay, clay loam soils, compacted soils, crop production, deep tillage, freeze-thaw cycles, soil aggregation, soil compaction, soil penetration resistance, soil profiles, soil quality, soil structure, weather, winter, Montana
In recent years, there has been an increased global concern regarding the impact of soil compaction on crop production and soil quality in modern mechanized agricultural farming systems. Freeze-thaw processes influence the physical properties of soil, primarily soil compaction and structure. A 3-yr study was established in fall 2009 to investigate the effects of the dynamics of freeze-thaw cycles (FTCs) on soil compaction in a clay loam. Results showed that frequent FTCs over the winter alleviated a majority of soil compaction at the 0 – 30 cm depth. During winter 2009-2010, soil penetration resistance (PR) in compacted treatments under frozen conditions was reduced by 73, 68, and 59% at the 0 – 10, 10 – 20, and 20 – 30 cm depths, respectively, due to dynamic effects of FTCs on soil structure and particle configuration. In unfrozen compacted soils, PR was significantly reduced by approximately 52% in the top 0 – 30 cm of the soil profile presumably due to the biology of soil and disruptive effects of shrink-swell cycles caused by frequent wetting - drying processes. These results demonstrate that repeated FTCs can alleviate soil compaction, alter soil physical quality and create optimal soil conditions required for profitable growth of agricultural crops. The results from this study will save growers considerable time, money and energy resources currently required to alleviate soil compaction using other methods such as sub-soiling and deep tillage. We conclude that FTCs associated with typical winter weather conditions are the most effective and economical way to alleviate soil compaction, improve soil structure and aggregation through the dynamics of FTCs.