Impacts of Residue Removal and Tillage on Water Infiltration.

Continual removal of residue can have significant impacts on soil properties as well as crop productivity without the additional input of nutrients to offset those removed in the residue.  Water infiltration is an important aspect of soil health in regions that are limited on moisture and can have intense precipitation events.  A study began in 2014 at Akron, CO measuring the impact of residue removal and tillage on water infiltration.  Two tillage treatments, No-Till (NT) and Tilled (T) were incorporated with residue removal (NR) and no residue removal (R) on a continuous corn system (Zea mays). The Cornell Infiltrometer was utilized to measure 1)  time to first runoff,  2)  total water infiltrated and 3)  steady state infiltration.  Residue from the 2 treatments with residue removal were done in early April of 2014.  Plots were tilled immediately after residue removal.  Tillage was done with a disc.  Residue cover for the T/NR was approximately 13% while the NT/R plots had 89% cover.  Both NT/NR and T/R plots had approximately 55% residue cover.  Differences were observed in infiltration by residue management.  Where residue was not removed, infiltration was greater than when residue was removed regardless of tillage.  Positive impacts when residue remained in the field were observed for the 3 major factors of infiltration.  The time for measurement of first runoff was doubled when residue remained in the field and was left on the surface or incorporated.  When residue was removed, average time to observe runoff was approximately 110 seconds but when residue was not removed the average time to observe runoff was 235 seconds.  The total water infiltrated in 30 minutes was approximately 0.50 inches greater when residue was not harvested (1.36 inches vs 0.81 inches). Our results show that intensive precipitation events can better utilized when  residue remains on the soil surface, and irrigation depths can be increased without the potential of runoff.