Temporal Changes in Soil Physical Properties Due to Corn Residue Grazing and Baling.

A better understanding of how the impact of corn residue grazing and baling on soil properties changes with time across different seasons is needed. We assessed the impact of corn residue grazing and baling on select soil physical properties including penetration resistance, soil temperature, gravimetric water content and wind erodible fraction (< 0.84 mm aggregates) on temporal basis from March 2016 to August 2017 in an irrigated corn-soybean system in south central Nebraska. The study site is located near Clay Center and has four corn residue treatments replicated thrice: 1) baling 2) light grazing 3) heavy grazing and 4) control. Penetration resistance, temperature, and gravimetric water content was measured on monthly basis while wind erodible fraction was determined in spring, summer and fall. Data collected in 2016 suggest that measured soil properties are dependent on sampling time. In May, the compaction level of light grazing was 1.3 times higher than control and 1.4 times higher than baled plots. In June, baling had about 2 times lower compaction than other treatments while there was no differences in compaction among treatments in other months during 2016. On average, baling had the highest soil temperature (~3 ^oC) and lowest moisture (~20 %) content among treatments in spring and summer, 2016. In spring, compared to control, baling increased the wind erodible fraction by 2.3 times while grazing had no impact. Overall, results suggest that crop residue grazing and baling alters the soil physical properties and magnitude of impact varies with time of year.