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11	Antritranspirants as a Possible Alternative to the Eradication of Saltcedar Thickets Cunningham, Robert S., Brooks, Kenneth N., Thorud, David B. 12 April 1975 (has links) From the Proceedings of the 1975 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 11-12, 1975, Tempe, Arizona / The response of saltcedar (Tamarix pentandra Pall.) to several antitranspirants was evaluated in laboratory, greenhouse and small -scale field studies using potted plants. Anti - transpirants may provide a treatment alternative to the eradication of saltcedar thickets for water salvage objectives. Transpiration rates were reduced by 23 to 44 percent for 7 to 20 days in the greenhouse, and by 18 to 32 percent for 2 to 8 days in the field. No serious damage to the plants was apparent. One of the most effective antitranspirants considered for a hypothetical saltcedar thicket and a hypothetical operational treatment program, based on estimated cost data, would result in reallocated water costing approximately 55 dollars per acre foot for a single treatment. About 19 acres of saltcedar thicket would have to be treated to provide one acre -foot of reallocated water in this case. Hydrology -- Arizona. Water resources development -- Arizona. Hydrology -- Southwestern states. Tamarisk Antitranspirants Water yield improvement Vegetation Chemcontrol Transpiration Control Land management
12	Diurnal Trends in Water Status, Transpiration, and Photosynthesis of Saltcedar Williams, Mary Ellen, Anderson, Jay E. 16 April 1977 (has links) From the Proceedings of the 1977 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 15-16, 1977, Las Vegas, Nevada / Relative water content (RWC), water potential (P), and gas exchange were measured on saltcedar at the Bernardo, New Mexico, lysimeter site. RWC and s were closely correlated; but, water potential measurements, taken with a pressure bomb, were more convenient and reliable. RWC and r decreased sharply from sunup until about 0900, when minimum values of about -26 bars T or 80% RWC were reached. Water status then remained constant or improved slightly through late afternoon. Transpiration rates typically remained high until about noon and then began a steady, gradual decrease that continued throughout the afternoon. The data suggest that water stress may be a factor in initiating stomatal closure; however, transpiration continued to decline despite a constant or improved leaf water status. Maximum net photosynthetic rates occurred by 0900, and depressions throughout the remainder of the day were largely accounted for by increased leaf temperatures. Afternoon depressions in transpiration and photosynthesis occurred in twigs held at constant temperature and relative humidity, suggesting that a diurnal rhythm may be involved in control of gas exchange. Water status of plants growing on the lysimeters was comparable to that of plants in adjacent natural stands; gas exchange rates were slightly higher for the lysimeter-grown plants. Hydrology -- Arizona. Water resources development -- Arizona. Hydrology -- Southwestern states. Tamarisk Diurnal Consumptive use Water utilization Transpiration control Photosynthesis Moisture uptake Moisture deficit Pores Respiration Water loss Stomata Lysimeters Plant physiology
13	Reducing Phreatophyte Transpiration Davenport, David C. 16 April 1977 (has links) From the Proceedings of the 1977 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 15-16, 1977, Las Vegas, Nevada / Transpiration rates (T) of riparian phreatophytes can be high. Antitranspirant (AT) sprays can curtail T without the ecological imbalance made by eradication. Saltcedar (Tamarix sp.) and cottonwood (Populus sp.) in 15-gal. drums enabled replicated trials on isolated plants or on canopies. T of isolate saltcedar plants could be 2x that of plants in a fairly dense canopy. T for a unit ground area of saltcedar varied from 2.2 (sparse -) to 15.8 (dense-stand) mm/day in July at Davis. Extrapolation of experimental T data to field sites must, therefore, be made carefully. Wax -based ATs increased foliar diffusive resistance (R), and reduced T of saltcedar and cottonwood 32-38% initially and 10% after 3 weeks. R increased naturally in the afternoon when evaporative demand was high and if soil water was low. Nocturnal T of salt cedar was 10% of day T. AT effectiveness increased with a higher ratio of day: night hours, and with lower soil water stress. Therefore, AT will be most effective on long summer days in riparian areas where ground water is available. Hydrology -- Arizona. Water resources development -- Arizona. Hydrology -- Southwestern states. Phreatophytes Transpiration Antitranspirents Transpiration control Chemcontrol Stomata Water conservation Water utilization Consumptive use Water yield improvement Balance of nature Thin films Desert plants Tamarisk Cottonwoods Arid lands Diurnal Nocturnal

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