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United States Department of Agriculture

Agricultural Research Service

2012 Annual Report

1a.Objectives (from AD-416):
To determine the impact of treated municipal waste water and other waste waters on soil physical and chemical properties and plant response (biomass, marketable yield and growth/appearance (turfgrass) and compare this response to that of degraded low organic natural waters.

1b.Approach (from AD-416):
To conduct laboratory and field research as needed to evaluate the use of treated municipal waste waters and other waste waters for irrigation of crops and turfgrass. This will include measurement of soil physical properties and plant growth and yield characteristics.

3.Progress Report:

The project is also related to objective 2 of the parent project 5310-61000-016-00D, objective 2: Improve our ability to predict the impact of degraded waters on infiltration into soils and plant response to irrigation with these waters. We have initiated an experiment on the cooperator fields University of California, Riverside, California (UCR) to evaluate the combined effects of drought and degraded water (saline and sodic) on turfgrass production and quality. Salinity and water sensors and soil solution samplers were installed in the field, ryegrass was planted, salts prepared and experiment initiated. Ryegrass is relatively salt sensitive but utilized as a winter overseeding grass in arid regions when Bermuda grass is used in either golf fairways or recreational lands irrigated with treated municipal waster water. We developed a line source sprinkler system with alternating lines of fresh and degraded water (electrical conductivity of 3 dS/m) - thus generating a continuum of salinities from one line in the field to the next. Along the line source we installed sprinklers of 4 different output volumes in different regions, from 130% of evapotranspiration to 60% of optimal evapotranspiration. Each water quantity treatment was replicated, thus enabling study of different irrigation quantities (under a range of salinity conditions). Results after 6 months indicated that stresses were cumulative, with the worst conditions being saline and water stressed. Any reductions in water application below optimal growth levels (100% of evapotranspiration) resulted in visual turf damage and reduction in turf clippings. Grass cover was lost at the highest salinity levels and lower water applications.

Last Modified: 7/25/2016
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