Residual effects of liquid digested sludge on the quality of broomsedge in a pine plantation.

Broomsedge (Andropogon virginicus L.) is generally looked upon with some disfavor as a weed but has been utilized for grazing. Liquid digested sludge (LDS)has been tested as a fertlllzer on tree plantations where broomsedge comprises a portion of the understory. Broomsedge samples were collected 4 years after treatment of a slash pine (pinus caribcrco More.) plantation with LDS containing 0, 21.6,40.5, 62.1, 83.7, and 102.6 t/ha of dry solids. Sludge was applied both as a top application and incorporated prior to tree planting. Crude protein (CP) of grass samples was generally increased with an increase in sludge application. In vitro organic matter digestfbllity (IVOMD) appeared to decrease with increased sludge application under conditions of top application only. The understory at the 0 and 21.6 t/ha-rates of sludge was about 67% broomsedge. At the higher sludge rates, the understory was only 10% broomsedge or less. Broomsedge bluestem (Andropogon virginicus L.) is found throughout most of the eastern U.S. and in several western states (Hitchcock 1935). Considered a pest, it has been called “Autumn’s Golden Glow” for its color changes with the weather and the light (Morris 1978). Voigt (1953) found that about 3 months of satisfactory grazing of broomsedge could be expected in southern Illinois. The grass has been accused of destroying the value of millions of acres of grazing land and hay meadows in the South as a result of encroachment (Thurman and Ward 1967). Broomsedge is not relished by livestock and is usually grazed only in the absence of more palatable grasses (Phillips Petroleum 1956). Considerable effort has been directed toward the control of broomsedge. Peters and Lowance (1974) indicated that fertilization of tall fescue (Festuca arundinacea Schreb.) and bluegrass (Poa pratensis L.) in pastures infested with broomsedge along with mowing of old growth of broomsedge and grazing by cattle resulted in broomsedge control after a period of years. Lowance et al. (1975) indicated the value of certain arsenical herbicides for removing broomsedge from forage grasses. Wolters and Schmidtling (1975) found that intensive culture of pine (pinus spp.) trees which included clearing, plowing, disking, and 3 post-planting diskings each growing season, with fertilization rates as high as 448-224-224 kg/ ha of NPK, reduced total broomsedge herbage production in pine plantations. Land application of sludge has received extensive attention in the last 30 years in the U.S. and England. Anderson (1955) and Bear and Prince (1955) reported beneficial effects from sewage sludge as a fertilizer and soil amendment. Coker (1966) found that liquid digested sludge (LDS) gave as large an increase in grass dry matter as equivalent fertilizers. He found that mean recovery of N applied in LDS was 84% of that recovered from equivalent inorganic fertilizer. Lutrick et al. (1976) obtained data indicating that