Seeding Rates and Grass Suppression for Sod‐seeded Red Clover and Alfalfa1

Abstract

AbstractSeeding rates needed for establishment of alfalfa (Medicago sativa L.) and red clover (Trifolium pratense L.) in perennial grass sod may differ from those needed for conventional establishment. The objective of this research was to determine the effect of seeding rate on alfalfa and red clover establishment and yield in the establishment year and in the spring after establishment when the legumes were sod‐seeded into perennial grass sods that received variable levels of herbicidal suppression.Field experiments were conducted at three locations on a Typic Hapludoll soil vegetated with smooth bromegrass (Bromus inermis Leyss.) at locations one (L1) and three (L3) and with smooth bromegrass, quackgrass (Agropyron repens L.), and Kentucky bluegrass (Poa pratensis L.) at location two (L2) Red clover and alfalfa were seeded at 4.4, 8.8, 13.2, and 17.6 kg/ha into grass sod sprayed with glyphosate [N‐(phos‐phonomethyl)glycine] at 1.7 or 0.6 kg/ha for high and low grass suppression levels, respectively.At L2, greater grass suppression occurred at each herbicide rate than at L1 and L3. At L1, where moisture was limited compared to L2 and L3, increasing the seeding rate resulted in significantly greater establishment year yields of both legumes at both grass suppression levels.Red clover yields were not affected by seeding rate at either grass suppression level at L2 or for the high suppression level at L3, but at L3, yield was significantly greater at either the 13.2 or 17.6 kg/ha rates than the 4.4 kg/ha rate for the low grass suppression treatment where high levels of grass competition existed. Total alfalfa yield was significantly greater for the 17.6 than the 4.4 kg/ha rate at the low grass suppression level at L2 and at the high grass suppression level at L3, both instances of high grass competition.For sod‐seeding, increasing legume seeding rate beyond that usually recommended for conventional establishment procedures appears to be beneficial to establishment only when grass competition is high.