Tall Fescue Rooting as Affected by Deficit Irrigation

Abstract

Deficit irrigation is increasingly used to conserve water, but its impact on turfgrass rooting has not been well documented. The objective of this study was to examine the effects of deficit irrigation on ‘Falcon II’ tall fescue (Festuca arundinacea Schreb.) root characteristics in the field using a minirhizotron imaging system. The experiment was conducted on a silt loam soil from the first week of June to mid-Sept. 2001 and 2002 using a mobile rainout shelter under which turf received applications of 20%, 60%, or 100% of actual evapotranspiration (ET) twice weekly. Neither soil water content (0 to 25 cm) nor tall fescue rooting between 4.1- and 50.1-cm depths was affected by irrigation at 60% compared with 100% ET. Despite consistently lower soil water content, tall fescue irrigated at 20% ET exhibited an increase in root parameters beginning in July or August. Tall fescue subjected to 20% ET irrigation had greater total root length and surface area on two of five monitoring dates in 2002 compared with that receiving 100% ET. Evaluation of tall fescue rooting by depth indicated that root proliferation at 20% ET was occurring between 8.7- and 36.3-cm depths. As evaluated under the conditions of this experiment, turfgrass managers using deficit irrigation as a water conservation strategy on tall fescue should not be concerned about a reduction in rooting deep in the soil profile, and irrigation at 20% ET may result in root growth enhancement.