Management of alfalfa (Medicago sativa L.) for maximum yield and utilization in Delaware - Phase II

Project Number: DELX-002-90-3**

Researchers: Jones, E. R.; Swain, R. H.

Start Date: 01-Oct-90

End Date: 30-Sep-95

Performing Institution:** Agriculture and Natural Resources, Delaware State College, Dover, DE 19901

Research Objectives:

  • Determine the optimum cutting interval and fall harvest management regime for each of two fertility regimes.
  • Investigate the influence of potassium fertilization and residual soil level of potassium on yield and stand persistence under Delaware conditions.
  • Evaluate production potential and stand survival of several alfalfa cultivars.
  • Determine the potential of alfalfa as a pasture legume in grass mixtures.
  • Compare alfalfa hay productivity and quality to other potential hay crops.


All experiments will be established on Sassafras sandy loam (Typic Hapludults) soil at the Delaware State College Forage-Beef Research Farm near Kenton, Delaware. Complete randomized block replications will be utilized. Forage quality components will be measured, total digestible nutrients and digestible protein will be calculated. Stand density will be determined after first harvest each year.


The effects of 10-year application of variable rates of P-K fertilizer compared with five-year application of the same five treatments followed by five years of comparing residual soil levels with applied rates indicates that more than 232 but less than 464 kg ha-1 of potassium in a 7.5 ratio with phosphorus is necessary to maximize alfalfa dry matter and protein production, and maintain stands. A five-year evaluation of 20 alfalfa cultivars determined that forage production was not significantly different, CV=6%.

However, when m2 areas in each plot were dug after five-harvest years stand density and crown-root ratings were significant; an indication that producers should consider root disease incidence/stand density when using alfalfa in long rotations. Results suggest that alfalfa may be defoliated more frequently than current recommendations and the date of fall harvest may be more flexible than previous research in Delaware had indicated. Recommended rates of maintenance fertilizer and the P:K ratio may need to be altered to maximize forage production.

Alfalfa productivity was compared to other forage species or mixtures grown in Delaware. Either pure alfalfa or alfalfa-reed canarygrass produced significantly higher yields each year of the three-year study. Various legumes were no-tilled into established tall fescue sods. Significantly higher sward productivity was obtained from alfalfa. No-tilling into bermudagrass sod was not successful.

Publications: No publications reported this period.