G. J. Cuomo

Harvest frequency and burning effects on monocultures of 3 warm-season grasses

Harvest frequency and burning can affect forage yield of monocultures of switchgrass (Panicum virgatum L.), big bluestem (Andropogon gerardii Vitman), and indiangrass [Sorghastrum nutans (L.) Nash]. Current information is based largely on results from mixed stands. A field experiment was established in 1986, and from 1988 to 1991 treatments were applied with burning in March, April, or May plus an unburned control. Growing-season yield was measured by harvesting 1 (June), 2 (June and July), or 3 (June, July, and August) times with unharvested control plots included. End-of-season standing crop from all plots was determined after plants became dormant. Treatments were applied to the same plots annually and were arranged in a split-split plot, randomized complete block design. The main plot was species, subplot was burn date, and sub-subplot was harvest frequency. Burning reduced yields (p<0.01), and yields were lowest in plots burned in May. Burning reduced yields of indiangrass most (57%) and big bluestem least (15%). In 1989, plots harvested three times produced yields similar to plots harvested once for all species. By 1991, yields of plots harvested 3 times per growing-season were reduced (P=0.08) below those of plots harvested once. Yield response of species also varied across the study. Growing-season yields in 1991 were 113, 67, and 89% of 1989 yields for switchgrass, big bluestem, and indiangrass, respectively. Regardless of burning and harvest frequency combination, switchgrass produced as much or more herbage than the other species.

Fertilizer effects on common bermudagrass on a southwest Louisiana coastal plain soil

Abstract Common bermudagrass [Cynodon dactylon (L.) Pers] is a widely used forage on the shallow, droughty coastal plain in southwest Louisiana. Management inputs including fertilizer are typically minimal, even though common bermudagrass has proven as productive as Coastal bermudagrass on these shallow soils. Lack of information about responsiveness of common bermudagrass to specific fertilizer treatments on these soils has led to an evaluation of sources of nitrogen (N) at two rates of N compared to a zero N control and the high N rate plus magnesium (Mg), sulphur (S), and boron (B). At 224 kg N/ha split into four applications, urea produced only 82% as much (P 0.05). Forage production from 448 kg N/ha as ammonium nitrate plus Mg, S, and B was 16% greater (P<0.05) than that from the same rate of ammonium nitrate without Mg, S, and B. Each increment of N produced small but distinct increases in crude prot...