Differences in Soil Water Use by Annual Broomweed and Grasses

Abstract

The use of water in the upper 1 m of the soil profile by 3 common herbaceous species of the southern Great Plains was examined by labeling soil water with 'Hz0 and Hzl*O. Uptake of

Soil moisture extraction by evergreen and drought-deciduous shrubs in the Mojave Desert during wet and dry years

“…The evergreen shrub Ephedra also extracted soil water in a fairly uniform manner to a depth of at least 1.95 m. These patterns of soil water depletion suggest that although rooting densities are low at greater depths, deep roots are important for soil water extraction. Greater water uptake from deeper soil depths, despite lower root densities at those depths, has been documented for a variety of species (Proffitt et al, 1985;Sharp & Davies, 1985;Wan et al, 1993;Yoder et al, 1998), and may be partially attributed to less suberization of deep roots relative to shallow laterals (Wan et al, 1994).…”

Summer rain pulse size and rainwater uptake by three dominant desert plants in a desertified grassland ecosystem in northwestern China

“…First, uptake by plants can alter dD of the ''bulk'' soil water if the roots are taking up water from a specific depth and thus removing water with a dD signature associated with that depth; this would cause the dD value of the bulk soil water to converge towards the dD values of layers from which plants are not actively taking up water. Second, hydraulic redistribution of water within the soil profile by roots would change the dD value of soil water (Yoder et al 1998). Accordingly, the dD values of stem water of the three dominant plants would be influenced by the potential evaporative enrichment and rainwater contamination Table 2.…”

Common Broomweed Growth Characteristics in Cleared and Woody Landscapes

“…In addition, mesquite was without leaves from December to April. The larger broomweed plants in the cleared treatment likely used more water and were more competitive with grasses than broomweed in the mesquite woodland (Yoder et al 1998). However, broomweed production was not significantly different between treatments, and we attribute the lower grass production in the woodland treatment to mesquite and not broomweed (Ansley et al 2004).…”

“…Broomweed growth is episodic and highly variable from year to year (Boyd et al 1983). During years of abundant growth, broomweed is problematic because it can reduce grass production, interfere with livestock foraging, and may even injure livestock (Heitschmidt 1979;Sosebee and Gordon 1983;Britton and Wester 1995;Yoder et al 1998). Herbicides have been used to mediate the negative impacts of annual broomweed infestations on livestock forage production (Scifres et al 1971;Boyd et al 1983).…”