Using strontium and rubidium tracers to characterize nutrient uptake patterns in creosotebush and mesquite

TitleUsing strontium and rubidium tracers to characterize nutrient uptake patterns in creosotebush and mesquite
Publication TypeJournal Article
Year of Publication1996
AuthorsHo M, Roisman R.E, Virginia R.A
JournalThe Southwestern Naturalist
Date Published1996
Accession NumberJRN00227
Call Number00684
Keywordsarticle, articles, isotopes, Rhubidium, isotopes, Strontium, journal, journals, Larrea, nutrient uptake, nutrient uptake, shrubs, Prosopis, nutrient uptake, Rhubidium, shrub, nutrient uptake, Strontium, tracer, Rhubidium, tracer, Strontium
AbstractDuring the past 100 years, large areas of perennial grassland in the Chihuahuan Desert have been replaced by woody plants such as mesquite (Prosopis glandulosa) and creosotebush (Larrea tridentata). WE investigated the short-term pattern of resource acquisition by these two dominant desert shrubs during the summer in the Jornada del Muerto Basin, New Mexico. We hypothesized that for a given class of shrubs, nutrient uptake favors isolated plants and that larger plants have higher access to soil resources. We applied tracer solutions containing Sr and Rb (0.02 M each) to patches of soil located either beneath or beyond the canopy of isolated creosotebush and mesquite shrubs to examine the ability of these plants to acquire nutrients as a function of distance. Tracer solutions were also applied equidistant between paired shrubs to examine whether neighboring plants had equal access to soil resources. Mature foliage was analyzed for Sr and Rb at day 7, 21, and 35 after tracer application. Strontium and Rb in creosotebush increased steadily at a relative accumulation rate of 0.018 per day. Mesquite accumulation rates were lower, 0.013 per day for Sr and 0.002 per day for Rb. The highest Rb concentrations were found in small creosotebush and mesquite were not equal and these differences between neighboring shrubs could not be explained by variation in canopy volume. Creosotebush and mesquite had distinct uptake patterns for the two tracers indicating these species differ in surface root distribution and activity. Creosotebush appears to respond more rapidly to short-term increases in the availability of soil moisture and nutrients.