Effects of tillage management on preferential subsurface flow and the transport of nutrients in agricultural systems in the Palouse.
Over the last several years growers have experienced wet spring conditions in the Palouse Region. As a result, growers are installing more artificial drainage to deal with excess precipitation. There has also been widespread adoption of no-tillage practices to reduce runoff and erosion over the last 30 years. There is a growing body of evidence that suggests long-term no-tillage practices may lead to the establishment of macropore networks through the preservation of earthworm burrows and root channels. These macropores may act as preferential flow paths that largely bypasses the soil matrix. The combination of preferential flow paths and the presence of artificial tile lines may be leading to the degradation of surface water quality in the region by increasing nutrient loading. The primary goal of this study is to compare the effects of long term tillage management practices on the timing and location of subsurface preferential flow using distributed temperature sensing (DTS). DTS is capable of obtaining accurate temperature measurements (0.1°C) along fiber-optic cables at a spatial resolution of 1.01m. In this study (November 2016 to April 2017) temperature was used as a tracer as snowmelt moved to two artificial drain lines under different tillage management, one draining a conventional tillage field and the other draining a no-till field. The frequency of distinct temperature drops (> 0.35 °C) along the no-till drain line was found to be greater, on average over twice as many, as compared to the conventional till field. It is hypothesized that preferential flow is responsible for the increased frequency of temperature drops. Additionally, temperature in the conventional till field responded more slowly to snow melt events indicating matrix flow was the predominate flow mechanism. Nitrate concentrations were also found to be greater and more temporally variable throughout the season on the no-till field.
I grew up in Upstate New York and attended Ithaca College where I received my undergraduate degree in Environmental Science. After graduating I worked with the Alaska Department of Fish and Game’s Habitat Division and then as a Fish Habitat Technician for the Idaho Department of Fish and Game. I felt the desire to obtain my master’s degree and began working under Dr. Erin Brooks in 2016 at the University of Idaho. I love the outdoors especially skiing and fly fishing, and going on adventures with my partner in life Emma.