Evapotranspiration from riparian vegetation: Conserving water by reducing saltcedar transpiration

ABSTRACT:

Spraying phreatophytic saltcedar (Tamarix chinensis, Lour.) with a non-toxic, wax-based antitranspirant can reduce evapotranspiration (ET) without eradicating the vegetation and eliminating its benefits for soil erosion control and wildlife habitat. In field studies, an antitranspirant sprayed with a backpack mistblower reduced saltcedar ET 20 to 35 percent initially and 10 percent after a month. No ET reduction occurred when the antitranspirant was sprayed by helicopter because the large droplet size resulted in poor foliar adherence. Although a properly applied antitranspirant clearly reduces the irrecoverable loss of pure water through transpiration, an operational program for antitranspirant spraying on phreatophytes cannot be recommended because of (1) the high cost, (2) the need to improve aerial application, and (3) the need to investigate more completely the effects of antitranspirants on wildlife. In the future, as water becomes more scarce and costly, antitranspirant spraying programs, with improvement, may become economical in preventing irrecoverable water losses.