Effect of Drought on Growth, Carbohydrates, and Soil Water Use by Perennial Ryegrass, Tall Fescue, and White Clover

Abstract

In irrigated pastures of the semiarid, high‐elevation western USA, perennial ryegrass (Lolium perenne L.) persistence is poor, and over time white clover (Trifolium repens L.) often dominates mixtures. Irrigation is often not available during autumn, when these perennial plants store carbohydrate reserves for spring regrowth. Our objective was to compare the effect of water stress on growth, carbohydrates, and soil water use of perennial ryegrass, white clover, and tall fescue (Festuca arundinacea Schreb.) in a greenhouse study. These three species were grown separately in a Kidman fine sandy loam, in 15‐cm‐diam, 1‐m‐deep pots and irrigated for 81 d (4 plants/pot). Paired pots were then either irrigated or subjected to water deficit (drought) for 30 d, followed by 10 d of recovery with irrigation. At 10‐d intervals, four paired pots of each species were destructively sampled to determine leaf and storage organ dry matter and carbohydrate and simple sugar concentrations in storage organs. Root length density and soil water content were also sampled at 20‐, 60‐, and 90‐cm soil depths. Leaf dry matter was lower in water‐stressed plants than in irrigated plants by the end of the drought, but did not differ among species. After 10 d of recovery, storage carbohydrate concentration in droughted perennial ryegrass was lower than in white clover, and the ratio of simple sugars (droughted:irrigated) in perennial ryegrass was higher than in white clover. Tall fescue performed similarly to both species. Before the drought, grasses had similar, extensive root systems that withdrew more soil water from the 90‐cm soil depth than did white clover. By the end of the 30‐d drought, white clover had reduced soil water at all depths as much as the grasses. White clover survived drought and conserved carbohydrate reserves after 10 d of recovery better than did perennial ryegrass and similarly to tall fescue.

Response of temperate grasslands at different altitudes to simulated summer drought differed but scaled with annual precipitation

“…Arp et al, 1998;Karsten and MacAdam, 2001), research at the ecosystem level in the field used two approaches: (1) naturally occurring droughts and their impact on the long-term field trials (Weaver et al, 1935;Gibbens and Beck, 1988; Bollinger et al, 1991;Stampfli and Zeiter, 2004) and (2) field experiments manipulating rainfall amounts. Such manipulation studies have been carried out in arid or semi-arid regions where drought is occurring frequently (e.g.…”

Competitive advantage of Rumex obtusifolius L. might increase in intensively managed temperate grasslands under drier climate

“…Armstrong and Castle, 1992;Mangan et al, 2004) or small-scale pot experiments performed in a greenhouse (e.g. Patterson, 1988;Karsten and MacAdam, 2001). In addition, the focus was often on semi-arid (e.g.…”

Strategies for Selecting Drought Tolerant Germplasm in Forage Legume Species

“…As well, under drought conditions it does not reduce stomatal conductance, as many other forage species do (Karsten & MacAdam, 2001). Consequently, in central Chile, where a Mediterranean climate predominates, white clover is cultivated exclusively under irrigated conditions.…”