Sorghum Response to Saline Industrial Cooling Water Applied at Three Growth Stages
- April L. Ulery and
- Frederick F. Ernst
Saline wastewater from industrial or agricultural sources may be an alternative irrigation supply in arid regions if effective crop and water management strategies for their use are developed. A field experiment was conducted to determine if grain yields of sorghum [Sorghum bicolor (L.) Moench] irrigated with undiluted saline wastewater from cooling towers of an electrical power generation plant can be significantly increased by applying nonsaline water at a critical growth stage. The wastewater had an average electrical conductivity (EC) of 0.67 S m−1 and was high i n CaSO4. Plot studies were conducted for 4 yr using conventional cultural practices and sprinkler irrigation on Tujunga loamy sand—Hanford fine sandy loam soil (mixed, thermic Typic Xeropsamment—coarse-loamy, mixed, nonacid, thermic Typic Xerorthent). Highest grain yields were obtained from the nonsaline control plots and from treatments that received nonsaline water during either the vegetative or reproductive growth stages. Plant height decreased in response to salinity, and differences between treatments were apparent by 27 d after planting. Plant height and grain yield were both negatively correlated with soil salinity by the 3rd yr of the experiment. Over an extended length of time, the best treatment for maximizing yield and utilizing saline wastewater is the application of nonsaline water early in the season to germinate and establish seedlings, followed by saline water during the grain-filling stage.
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