Influence of soil texture on hydraulic properties and water relations of a dominant warm-desert phreatophyte

Abstract

We investigated hydraulic constraints on water uptake by velvet mesquite (Prosopis velutina Woot.) at a site with sandy-loam soil and at a site with loamy-clay soil in southeastern Arizona, USA. We predicted that trees on sandy-loam soil have less negative xylem and soil water potentials during drought and a lower resistance to xylem cavitation, and reach E(crit) (the maximum steady-state transpiration rate without hydraulic failure) at higher soil water potentials than trees on loamy-clay soil. However, minimum predawn leaf xylem water potentials measured during the height of summer drought were significantly lower at the sandy-loam site (-3.5 +/- 0.1 MPa; all errors are 95% confidence limits) than at the loamy-clay site (-2.9 +/- 0.1 MPa). Minimum midday xylem water potentials also were lower at the sandy-loam site (-4.5 +/- 0.1 MPa) than at the loamy-clay site (-4.0 +/- 0.1 MPa). Despite the differences in leaf water potentials, there were no significant differences in either root or stem xylem embolism, mean cavitation pressure or Psi(95) (xylem water potential causing 95% cavitation) between trees at the two sites. A soil-plant hydraulic model parameterized with the field data predicted that E(crit) approaches zero at a substantially higher bulk soil water potential (Psi(s)) on sandy-loam soil than on loamy-clay soil, because of limiting rhizosphere conductance. The model predicted that transpiration at the sandy-loam site is limited by E(crit) and is tightly coupled to Psi(s) over much of the growing season, suggesting that seasonal transpiration fluxes at the sandy-loam site are strongly linked to intra-annual precipitation pulses. Conversely, the model predicted that trees on loamy-clay soil operate below E(crit) throughout the growing season, suggesting that fluxes on fine-textured soils are closely coupled to inter-annual changes in precipitation. Information on the combined importance of xylem and rhizosphere constraints to leaf water supply across soil texture gradients provides insight into processes controlling plant water balance and larger scale hydrologic processes.

Hydraulic lift through transpiration suppression in shrubs from two arid ecosystems: patterns and control mechanisms

“…On the other hand, coarse-textured soils (sandy, loamy sand or sandy loam) usually have lower field capacities (lower h s values) and thus are less able to hold large amounts of water (Hillel 2004;Bristow 1984). Consistent with other reports, the amount of water that can potentially be redistributed into the soil is thus dependent on soil texture, with coarsetextured soils being less conducive to HL (Yoder and Nowak, 1999;Hultine et al 2006;Siqueira et al 2008;Wang et al 2009). The relationship with texture becomes nonlinear in more clayish soil types, which have intermediate properties between sandy and loamy soils regarding HL.…”

Effects of Hydrogel Amendment to Different Soils on Plant Available Water and Survival of Trees under Drought Conditions

“…This movement of water can go so far that even in trees water can move from the trunk via the roots back to the soil [29,30] and the water may also be made available for neighboring plants [31,32]. The hydraulic conductivity of the soil is influenced by the particle size distribution of the soil [32] and is a function of the soil texture [33]. Amendment with hydrogels decreases the hydraulic conductivity of soils [34].…”

Wide‐area estimates of saltcedar (Tamarix spp.) evapotranspiration on the lower Colorado River measured by heat balance and remote sensing methods

“…Soil texture in the aquifer differed among sites and can limit the rate of transpiration that can be supported in phreatophytes (Hultine et al, 2006). Sands, as at Diablo East, produce cavitations at the root-soil interface at much lower critical transpiration rates than in heaviertextured soils, as occurred at Slitherin and Swamp (Sperry et al, 1998).…”