Commercial Production of Wheat Grain Irrigated with Municipal Wastewater

Abstract

Experiments were conducted in southern Arizona to study the effects of irrigating wheat (Triticum aestivum L.) with a mixture of pump water and wastewater and pump water alone on wheat growth, grain yield, grain quality, soil properties, and irrigation water quality. In small plot research, wheat irrigated with a mixture of pump water and wastewater produced taller plants, more heads per unit area, heavier seeds, higher grain yields, and higher straw yields than did wheat grown with only pump water. When large fields were compared, wheat grown with a mixture of pump water and wastewater had taller plants, more lodging, lower grain volume-weights, and higher grain yields than did wheat produced with pump water. The pH and exchangeable sodium of soil irrigated with pump water alone or a mixture of pump water and wastewater were similar. Electricalconductivity and nitrate-nitrogen were higher in soils irrigated with pump water than they were in soils irrigated with a mixture of pump water and wastewater. Extractable phosphorus was higher in soils irrigated with a mixture of pump water and wastewater than in soils irrigated with pump water. Total soluble salts and nitrate-nitrogen were higher in pump water than they were in the pump water and wastewater mixture; however, the pump water and wastewater mixture had a higher level of phosphorus than did pump water.