||Tallgrass prairies are an important forage resource in the eastern Central Great Plains. The effect of spring burning, fertilization,
and atrazine [6-chloro-N-ethyl-N’-(l-methylethyl)-l,3,5-triazhre-2,4diamine] on standing crop of selected herbaceous species and
categories of vegetation was determined in 6 tallgrass prairie environments located near Lincoln and Virginta, Neb., from 1987
through 1989 and 1 site near Bloomfleid, Neb., in 1987. The grasslands were in good to excellent condition at the time these
studies were conducted. Portions of each site were burned in mid-to late spring, atrazine was applied at a rate of 2.2 kg a.i. ha-’ in
late April to early May, and fertilizer was applied in mid-May. Despite below-normal precipitation at 6 of the 7 sites, burning
combined with fertilization improved warm-season grass standing crop by 50 to 127% in 5 of the 7 grassland environments studied.
This reflected the positive response of the dominant warm-season grasses, big biuestem (Andropogon gerurdii Vitman var. gerardii
Vitman) and indiangrass [Sorghustrwn nulons(L.) Nash], to burning or fertilization. Atrazine increased warm-season grass standing
crop at only the site near Bloomfield. Kentucky bluegrass (Poe pratensis L.) and annual bromes (Bromuz spp.) were more susceptible
to atrazine than smooth brome (Bromus inermis Leyss.). Forb standing crop was significantly reduced by atrazine alone or by
burning followed by atrazine application in 4 of the 7 prairie environments. Burning combined with fertilizer application improved
warm-season grass standing crop in good to excellent condition grasslands and obviated the need to use atrazine.