Drought is a common occurrence in the Great Plains and an understanding how temporal precipitation patterns affect range plant communities is critical in grazing management decisions. Current rainfall models project that rainfall events will increase in intensity and decrease in frequency. Our objective was to evaluate the effects of differing rainfall amounts at different time intervals on above-ground plant production and plant community composition on Nebraska Sandhills rangelands. Using rainout shelters, total exclusion of rainfall was implemented from May 9 through August 22 during the 2017 growing season. Using an irrigation system, simulated rainfall was applied to individual rainout shelters on a sands ecological site to determine the effects of temporal distribution of precipitation. Water amounts were applied at 50% of average annual rainfall and at 125% of average annual rainfall at intervals of once every week, once every three weeks, and once every five weeks. There were five replications of all intensity-by-frequency combinations. A control treatment of excluding all rainfall (0% of average annual rainfall) also was included as a baseline. Plant response was measured as basal cover by plant species, using the line-intercept method, and above-ground plant production as measured by hand-clipping in August. Soil moisture was measured weekly in each plot using Time-Domain Reflectometry (TDR) at depths of 0-20 cm, 21-40 cm, 41-60 cm, 61-80cm and 81-100 cm. The volumetric water content of the once-per-week plots were similar or greater than the three and five-week plots through the growing season for both watering intensities. Treatment plots steadily decreased across all treatments through the duration of the experiment except for the 125% weekly watering treatment. Plant production data is in the process of being analyzed and will be presented.
Oral presentation and poster titles, abstracts, and authors from the Society for Range Management (SRM) Annual Meetings and Tradeshows, from 2013 forward.