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ARS Home » Plains Area » Las Cruces, New Mexico » Range Management Research » Research » Publications at this Location » Publication #98794
Title: STEMFLOW CONTRIBUTION TO THE "FERTILE ISLAND" EFFECT IN CREOSOTEBUSH, LARREA TRIDENTATA

Author
item Whitford, Walter
item ANDERSON, JOHN - NEW MEXICO STATE UNIV
item RICE, PATRICIA - NEW MEXICO STATE UNIV

Submitted to: Journal of Arid Environments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/27/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Rain may reach the ground directly, through the shrub canopy or captured by the canopy and diverted along its stems (stemflow). On average about 17% of rain was diverted to stemflow while about 65% fell through creosotebush canopies. Stemflow water had higher concentrations of various substances including nitrogen, sulfate and calcium. Concentrations of these substances was also higher in the upper 10 cm of soil under shrubs compare to areas between shrubs. The high mineral concentrations in stemflow may be due to the activity of stem micro-organisms and the collection of "dust" from the air, all of which may add to the "fertile island" effect of soil under creosotebushes.

Technical Abstract: Stemflow, throughfall and bulk precipitation were collected on six creosotebushes (Larrea tridentata) during 18 events in the summer rainy season in the northern Chihuahuan Desert. The average stemflow was 16.8 +/- 1.9%; throughfall averaged 64.7 +/- 3.2%. The concentration of all ions measured were significantly higher in stemflow than in the bulk precipitation. Total nitrogen, sulfate and calcium concentrations were more than an order of magnitude higher in the stemflow than in the bulk precipitation. Concentrations of ions in the upper 10 cm of soil were generally higher in soils under shrubs than in soils between shrubs. Measured quantities of ions in dry-fall were of sufficient magnitude to account for the increased concentration in stemflow water of most ions. Increases in nitrogen in stemflow water may be due to biological activity of stem crust micro-organisms in addition to dry-fall. Dry-fall that collects on the leaves and stems of this desert shrub may contribute to th "fertile island" effect on the soils under the canopies of creosotebushes.