Response of two perennial grasses to root barriers and fissures

Aboveand belowground biomass of contrasting grass growth forms (Hilaria belangeri— shortgrass vs. Bouteloua curtipendula—mid-height grass) was quantified with respect to partial root barriers (at 35 cm soil depth) with artificial fissures. We hypothesized (a) growth would be greatest in the absence of a barrier; and (b) the shallow-rooted H. belangeri would be relatively less affected by barriers with fissures than B. curtipendula. Alternatively (c) B. curtipendula with its deeper root system would exploit fissures and access the resources below barriers better than H. belangeri. The parameters used to evaluate these hypotheses for plants grown in subirrigated 150 cm pots included aboveand belowground biomass after 4 months and monthly gravimetric soil moisture at 20 cm intervals to 150 cm. Root barrier treatments had no affect on either species’ above-ground growth. As expected, the mid-height grass produced more root biomass and was more deeply rooted. However, partial root barriers had no effect on total root biomass for either species. Although, some ‘perching’ of root biomass above the barrier occurred in both species, it had no discernable influence on the pattern of soil moisture depletion with depth. Thus, under the conditions of this experiment, the lack of a significant see front matter r 2004 Elsevier Ltd. All rights reserved. .jaridenv.2004.09.002 nding author. Department of Earth and Environmental Science, The University of Texas at , San Antonio, TX 78249-0663, USA. Tel.: +1210 458 5443; fax: +1 210 458 4469. dress: [email protected] (P.N. Jurena). dress: School of Renewable Natural Resources, 325 Biological Sciences East, University of son, AZ 85721-0043, USA.