Jt. Bushoven et al., Stabilization of soil nitrate by reseeding with perennial ryegrass following sudden turf death, J ENVIR Q, 29(5), 2000, pp. 1657-1661
Turf death can result in the mineralization of organic nitrogen (N) within
the turf-soil ecosystem. if not reestablished within 12 mo, dead turf can l
each 10% of its total soil N as nitrate into ground water. This study inves
tigated how rapidly and completely soil N fan be restabilized following res
eeding of killed turf. Twelve-year-old field plots, comprising four cool-se
ason turfgrass species growing on an Enfield silt loam (coarse-silty over s
andy-skeletal, mixed, active, mesic Typic Dystrudepts) at Kingston, RI, wer
e used. In early September 1997, one-half of the plots were killed by apply
ing glyphosate and three-fourths of the dead plots were reseeded with 'Palm
er III' perennial ryegrass (Lolium perenne L.) in late March 1998. Soil moi
sture, temperature, pH, respiration, and extractable nitrate and ammonium w
ere monitored every 6 to 8 wk. Nitrate levels in subsoil water were monitor
ed at 2-wk intervals and nitrate leaching estimated for each percolation ev
ent. Reseeding enhanced soil respiration, within 6 wk of seeding, to levels
comparable with those of soil in healthy plots. Surface soil nitrate level
s in killed and reseeded plots declined within 6 wk of reseeding. Nitrate l
evels in soil water beneath the root zone declined in reseeded plots relati
ve to those of healthy plots (9 mg NO3-N L-1) within 8 wk of reseeding. Nit
rate leaching also declined 3 mo after seeding to rates less than half of t
hose from turf that had been killed but not reseeded. Our results indicate
that the potential for increased nitrate leaching following turf death can
be eliminated within 2 mo if the site is promptly reseeded.