Understanding and Controlling Hillslope Hydrology to Assess Water Quality within Sustainable Dairy Manure Management.

Prudent management of manure resources on agricultural lands is critical to protecting air and water quality. Over the past few years there has been considerable interest in promoting technologies that incorporate manures into soils without significant tillage. Surface application leaves manure vulnerable to environmental processes that enrich surface runoff with dissolved nutrients and increase emissions of ammonia and odor to the atmosphere. Understanding the agronomic and environmental trade-offs of different manure application technologies is important to their sustainable use. In this study, we established twelve field-scale lysimeters (15 meters by 27 meters) on the Kepler Research Farm near Rock Springs, PA. Six lysimeters were treated with a conventional surface application of dairy manure (rate = 62.7tonnes/ha), whereas the other six lysimeters received subsurface application of manure using the shallow disk injection technology. These lysimeters provide an excellent method of monitoring nutrient movement within a sustainable system, but they do come with their own variability. In analyzing the data collected from these plots, environmental and landscape variability has become a significant part of how the data collected can be applied. Through GPR (ground penetrating radar) data and topographic wetness index modeling we hope to start to understand some of the site variability. Tackling some of these variability issues may help answer data interpretation questions, grouping of plots and how to manage future research projects conducted on the field lysimeters.