Two-Year On-Farm Study of Crop Residue Removal On Soil Erodibility.

Residue removal for livestock and biofuel production at large scales may degrade soil productivity and properties. We conducted the on-farm study by removing crop residue at five levels (0, 25, 50, 75, and 100%) to determine the impacts of crop residue removal on soil properties such as soil wind erodible fraction (EF <0.84 mm aggregates), geometric mean diameter (GMD) of dry aggregates, dry aggregate stability, soil surface roughness, wet aggregate stability, infiltration rate, total C and total N content in the surface soil, and biomass yield. Five crop residue removal treatments with four replications were established after wheat harvest in 9 m by 9 m plots on six farmer’s no-till fields in western Kansas in summer 2011. Crop residue was cut with a forage harvester at different heights corresponding to the five treatments. Soil samples from the 0- to 5-cm depth were taken in fall 2011, spring 2012, fall 2012, and spring 2013 for evaluation of wind erosion parameters.

Four months after residue removal, the EF increased between 5 and 10% after 100% residue removal rate in four of the six sites. Eight months after residue removal, the EF increased between 7 and 37% after 100% residue removal in all six sites. In 3 sites out of 6, EF reached maximum levels at plots with more than 75% residue removal after 1 year. Five sites showed that the increase in EF reached a peak at 8 months after residue removal for the 100% removal plots. Also, residue removal generally reduced GMD of dry aggregates and soil surface random roughness. Dry aggregate stability decreased by 15 to 27% with 100% of removal at four sites in spring 2012. Current results suggest that excessive (> 75%) crop residue removal can rapidly increase soil’s susceptibility to wind erosion in some soils.