ARIZONA COOPERATIVE ALFALFA FORAGE YIELD TRIAL

2012-2014

Background information on alfalfa yield trials at Tucson, AZ

The Arizona Cooperative Alfalfa Forage Yield Trial Program, which is administered by the Arizona Agricultural Experiment Station and Arizona Cooperative Extension, conducts forage yield trials at the University of Arizona's Campus Agriculture Center (CAC). CAC is located at an elevation of 2500 feet, approximately 5 miles north of the University of Arizona Campus in Tucson. Very nondormant cultivars are well adapted to this environment, which is typical of agricultural areas of central and western Arizona where 8 to 10 harvests of alfalfa are common each year and stands typically remain productive for 2 to 4 years. All fields at CAC are laser-leveled and alfalfa is irrigated using border-strip methods on sandy loam soils. Total dissolved salts in irrigation water range from about 400 to 800 ppm. Planting, harvest, and data reporting procedures will be as in the 2010-2012 trial.

Experimental conditions and data reporting

Each 12 foot long plot in these four-replication trials contains five rows spaced 6 inches apart. The equivalent of 20 pounds per acre was sown (7.5 g per plot, 30 g total) using a cone seeder on 12 March 2013. Plots are harvested with a Jari mower and weighed fresh. Plots are arranged so that wheel traffic does not confound evaluation of performance. All cultural practices common on farms in central Arizona are typically followed at CAC.

Results are updated following each harvest on this website. Updates include the yields in the most recent harvest as well as the running total yield. Yields are presented on the basis of tons of dry forage (88% dry matter) per acre. Data will be distributed to cooperators as requested and published in the Forage and Grain Report, which is widely distributed by Arizona Cooperative Extension personnel.

The trial is located within a 30 minute drive of Tucson International Airport and all cooperators are welcome to visit the trial. If you have any questions, contact Steve Smith at azalfalf@ag.arizona.edu

Yield data

Mixed-model analysis for a randomized complete block design is used with nearest-neighbor yields used as a covariate (see Casler, M.D. 1999. Spatial variation affects precision of perennial cool-season forage grass trials. Agron. J. 91:75-81). Least-squares means from the mixed-model analysis are presented in order of decreasing total yield. The estimate for the residual is used to generate the least significant difference value reported.

NOTE: DUE TO UNUSUALLY LOW WINTER AND SPRING TEMPERATURES THE FIRST HARVEST WAS DELAYED UNTIL 15 JULY 2013

Forage yields reported as tons of dry matter (12% moisture)/acre.