Effects of Municipal Wastewater Effluent and Cutting Management on Root Growth of Perennial Forage Grasses1

Abstract

AbstractMunicipal wastewater effluent studies have not evaluated perennial forage root growth at different effluent rates or cutting sequences. Our primary objective was to ascertain whether root length and mass of perennial grasses, that are tolerant of wastewater effluent, but that yield differently depending on frequency of cutting, are influenced by effluent application or cutting frequency. The two, three, or four‐time year−1 cutting sequence had little effect on root length or dry weight, whereas wastewater treatment levels caused significant root differences. The high effluent (10 cm week−1) treatment produced less root length and root mass in all four species compared with the control and low effluent (5 cm week−1) treatments. When high levels of effluent were applied, reed canarygrass (Phalaris arundinacea L.) had the greatest root length and mass, whereas orchardgrass (Dactylis glomerata L.) had the least; tall fescue (Festuca arundinacea Schreb.) and Kentucky bluegrass (Poa pratensis L.) had intermediate root production. Although orchardgrass produced significantly fewer roots than did reed canarygrass, previous work had shown the aboveground yields of these species were comparable. Also, the high effluent treatment produced the greatest yield of aboveground dry matter, the finest roots, the least root dry matter, and lowest rooting density. We concluded that root mass or length were not primary determinants of forage production of adapted perennial grasses when ample water and nutrients were provided by wastewater effluent.