Impacts of Residue Removal and Tillage on Water Infiltration and Soil Properties.

Residue removal can alter crop productivity as well as soil properties because nutrients like N and C are removed with the residue.  Good water infiltration is essential in regions like the Central Great Plains because precipitation events are intense and can lead to soil erosion and reduced profile water recharge.  A study began in 2014 at Akron, CO measuring the impact of tillage and residue removal on water infiltration soil C and soil enzymes.  Two tillage treatments, No-Till (NT) and Tilled (T) were combined with residue removal (NR) and no residue removal (R). The Cornell Infiltrometer was used to measure 1)  time to first runoff,  2)  total water infiltrated and 3)  steady state infiltration.  Residue redistribution from the 2 treatments with residue removal was done in the spring of 2014 and 2015, and the plots were tilled after residue removal with a disc.  In 2014, residue cover for the T/NR was 13% while the NT/R plots had 89% cover.  Both NT/NR and T/R plots had 55% residue cover.  Residue management affected infiltration.  In the R treatment, infiltration was higher than in NR, regardless of tillage.  Time to first runoff,  total water infiltrated and steady state infiltration were positively impacted by the R treatment.  The time to first runoff doubled in the R treatment regardless of incorporation.  The total water infiltrated in 30 minutes was greater in the R than NR.  Keeping the residue and incorporating it also increased the activity of C cycling and N cycling enzymes in soil. Thus, intensive precipitation events be used more efficiently when  residue remains in the field, indicating that crop residue have value beyond their nutrient content.