Summer Drought Response and Rooting Depth of Three Cool-season Turfgrasses

Abstract

Abstract This study was conducted to determine root distribution, soil moisture depletion, and 32 P uptake, as an indicator of water absorption, by Kentucky bluegrass ( Poa pratensis L. ‘Fylking’), perennial ryegrass ( Lolium perenne L. ‘Manhattan’), and tall fescue ( Festuca arundinacea Schreb. ‘Kentucky 31’). 32 P was injected at 6, 18, 30, 42, and 54 cm from the soil surface under each turfgrass plot on 18 July 1978. Leaf blade radioactivity revealed differences in uptake among species, but was inconsistent with rooting patterns. Root mass measurements below 36 cm in late August showed tall fescue > perennial ryegrass > Kentucky bluegrass. Root mass above 12 cm showed Kentucky bluegrass > tall fescue = perennial ryegrass. Soil water content (SWC) at three depths in August reflected root distribution for the three species. SWC was lowest under Kentucky bluegrass and highest under tall fescue at 6 cm. At 54 and 78 cm, SWC was highest under Kentucky bluegrass and lowest under tall fescue. SWC was better than 32 P injection for detecting species differences in water uptake.