The MAMA experiment (Manure Application Methods for Alfalfa-Grass) was designed to evaluate nutrient and pathogen losses with conventional and improved liquid dairy manure management practices for alfalfa-grass production. Observations from MAMA have also been used for parameterization and validation of computer simulation models of greenhouse gas (GHG) emissions from dairy farms (Gaillard et al., in preparation). The experiment included five treatments: shallow injection of manure, aerator/banded manure (subsurface deposition), banded manure (trailing foot application), broadcast manure, and no manure (i.e. control). The five treatments were replicated three times in a randomized complete block design. This experiment was performed as part of the Dairy CAP, described below.

The experiment was conducted at the Marshfield Research Station of the University of Wisconsin and the USDA Agricultural Research Service (ARS) in Marshfield, WI (Wood County, Latitude 44.641445, Longitude -90.133526). Soils at the research station are from the Withee soil series, fine-loamy, mixed, superactive, frigid Aquic Glossudalf, with 2% slope. Each of the fifteen experimental plots was approximately 7.3 x 12.8 meters, oriented across slope. A weather station was at the south edge of the research field and centered east-west. A weather station for snow data was located 420 meters south of the field.

The experiment was initiated on May 16, 2013 by planting alfalfa (Medicago sativa) on plots that were in a corn (Zea mays) and soybean (Glycine max) rotation during the previous five years. All plots were planted with cultivar "Nexgrow-6422Q 19," using a 10-foot Brillion forage seeder. Planting rate was 19 kg seed per hectare. Alfalfa forage was harvested by cutting at 3 inches (~8 cm) height. Alfalfa was harvested once in 2013, three times in 2014 and 2015, and four times in 2016. Forage characteristics were measured at the University of Wisconsin Soil and Forage Lab in Marshfield (total P and total K) and at the Marshfield ARS (dry matter, total N and total C)

The manure applied in this experiment was from the dairy herd at the Marshfield Research Station. Cows were fed a diet of 48% dry matter, 17.45% protein, and 72.8% total digestible nutrients. Liquid slurry manure, including feces, urine, and bedding, was collected and stored in a lagoon on the site. Manure was withdrawn from the lagoon, spread on the plots and sampled for analysis all on the same day, once per year shortly after an alfalfa harvest. Manure samples were analyzed at the University of Wisconsin Soil and Forage Lab in Marshfield (NH4-N, total P and total K) and at the Marshfield ARS (pH, dry matter, volatile solids, total N and total C).

GHG fluxes from soil (CO2, CH4, N2O) were measured using static chambers as described in Parkin and Venterea (2010). In addition, ammonia fluxes (NH3) from soil were measured using a dynamic chamber method (Svensson, 1994; Misselbrook and Hansen, 2001). Additional soil chemical and physical characteristics were measured as noted in the data dictionary and other metadata of the MAMA data set, included here.

This experiment was part of “Climate Change Mitigation and Adaptation in Dairy Production Systems of the Great Lakes Region,” also known as the Dairy Coordinated Agricultural Project (Dairy CAP), funded by the United States Department of Agriculture - National Institute of Food and Agriculture (award number 2013-68002-20525). The main goal of the Dairy CAP was to improve understanding of the magnitudes and controlling factors over GHG emissions from dairy production in the Great Lakes region. Using this knowledge, the Dairy CAP has improved life cycle analysis (LCA) of GHG production by Great Lakes dairy farms, developing farm management tools, and conducting extension, education and outreach activities.