Conservation Tillage Impacts on Soil Quality Parameters Under Furrow Irrigation.

Furrow irrigation is still widely practiced in Colorado and it is expected to continue on a significant portion of acres in the State. Under furrow-irrigated systems, conventional tillage practices are commonly utilized to create a suitable seedbed and improve irrigation uniformity. However, such practices have a high-energy demand and often result in adverse effects on soil quality. The objective of this project is to examine the effects of conservation tillage on soil quality parameters on a furrow-irrigated field. Soil biological, physical, and chemical parameters were evaluated during the fifth and sixth years (2015 and 2016) of a study comparing two different management systems, minimum till (MT), and strip-till (ST), to a conventional till(CT) system (control). The study examined tillage effects on active carbon, macrofauna abundance and diversity, aggregate stability, infiltration, bulk density, soil hardness, EC, and pH. Results from 2015 and 2016 showed that conservation treatments statistically increased macrofauna abundance and diversity, specifically number of earthworms when compared to the control. Infiltration rates was slightly higher in the strip-till plots when compared to the control and minimum till plots.  In the conservation tillage plots, minimum till and strip-till, lead to a higher aggregate stability by 10-15% percent stability verse the control. The conventional plots commonly showed less compaction in the top 15 cm derived from penetrometer readings. There was no significant difference in EC between the treatments. These preliminary results demonstrate the feasibility in the use of conservation tillage under furrow-irrigation to improve soil quality parameters.