The Potential of Mixed Alfalfa/Bermudagrass Systems in Mississippi.

  The effect of seeding rate on mixed alfalfa/bermudagrass systems in Mississippi

Joshua White[1] and Rocky Lemus

Mississippi State University, Plant and Soil Science

Alfalfa is well adapted in many hay systems across the United States and has persisted in grazing situations under adequate rainfall and well-drained soils. In high precipitation regions like the southeastern USA, lack of moisture is usually not a limitation in forage systems which coupled with mild winters can prolong the grazing season.  In Mississippi, fertility issues often decrease profits of forage systems because of the high input needed to maintain quality hay and pastures of warm-season perennial grasses such as bermudagrass.  Alfalfa can possibly be interseeded into existing pastures and consequently prolong the growing season and improve forage quality with minimum fertility input. The study was a split-split plot design replicated 4 times.  A Roundup Ready^® alfalfa variety DKA41-18RR was planted at a rate of 17, 22 , 28 and 39 kg ha^-1 in the fall of 2011. Potash was applied according to the soil with no other fertility adjustments or nitrogen applications.   Alfalfa was harvested at mid-bloom, botanical composition was estimated using visual observations and dry matter yields were estimated by removing a 1.4 m x 1.82 m from the center of the plot.  Data was analyzed using generalized linear model of SAS and means separated when at α = 0.05. Total annual yields in 2012 and 2013 were similar at all seeding rates with the exception of the lowest rate planted at 17 kg ha^-1 which produced 13% less in 2012 than 2013.   In 2012, the April harvest was significantly affected by seeding rates with 39 (35) and 28 (25) Kg ha^-1 (lb ac^-1) producing the greatest forage yields; however the May and August harvests were not affected.   Alfalfa composition in the stand was greatest at the 39 (35) kg ha^-1 (lb/a)seeding rate and lower at the 17 (15) kg ha^-1 (lb ac^-1)  Percent alfalfa in the stand decreased up to 41% between the May and August harvest, but was not affected by a harvest and rate interaction.  In 2013, seeding rates did not affect yield or composition, but total yields were 7 % greater.  Increasing the seeding rate for alfalfa over 22 kg ha^-1 does not appear to be necessary to maintain stands in bermudagrass. In fact, increased rates may have been more detrimental to the bermudagrass stand in the first year.  Forage yield increased in the second year showing the potential of this system in Mississippi.       

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[1] Corresponding author  jwhite@pss.msstate.edu