Reservoirs and dugouts are valuable as temporary or seasonal sources of stock water. �They are dependent on surface runoff or seepage so may be empty or hold lower quality water when most needed in dry seasons due to evaporation and a lack of runoff.� Water contact with mineral soil may add solutes to retained water while evaporation may act to concentrate solutes.� Cattle standing in catchment water systems can agitate organic and inorganic matter. �The objective of this study was to determine if the concentration of total dissolved solids (TDS) in catchment water systems with active cattle grazing were influenced by frequency of precipitation events characterized by month.� To estimate spring/summer variation in water TDS concentrations, 2 livestock reservoirs (Flood on the eastern boundary and North 4 adjacent to the southern property line) were fitted with Troll 9500� continuous monitoring submerged TDS sensors in June through August 2016 at the 22,257 ha USDA-ARS Fort Keogh Livestock and Range Research Laboratory near Miles City, MT.�� Two sensors were placed in each reservoir.� The sensors recorded a reading every 1 hr at a depth of 3 feet.� Overall, 7889 records were logged. Data were analyzed as a completely randomized design testing the effect of month on TDS concentration using Proc. Mixed (SAS 2014).� The concentration of TDS differed (P < 0.01) in each month.� Total dissolved solids were 652.2 + 5.3, 851.1 + 5.1 and 1173 + 6.0 ppm for June, July and August respectively.� Concentrations of TDS increased 30% from June to July, 38% from July to August and 80% from June to August.� Water TDS content was elevated as the summer advanced.�� Monitoring TDS content may allow for livestock to be moved when declines in productivity due to elevated TDS are expected.
Oral presentation and poster titles, abstracts, and authors from the Society for Range Management (SRM) Annual Meetings and Tradeshows, from 2013 forward.