Effect of irrigation management on yield and water use efficiency of timothy hay in southern Alberta

Abstract

Timothy hay production for export markets has recently expanded on the Canadian prairies. Irrigation management information for timothy production is limited; therefore, irrigation practices to achieve optimum dry matter (DM) yield and water use efficiency (WUE) of timothy hay were investigated from 2005 to 2007 near Bow Island and Picture Butte, Alberta. Treatments were defined by managing irrigation using 0.25-m, 0.50-m, 0.75-m, and 1.00-m root zone depths with an allowable moisture depletion of 50% of available soil moisture. The 0.25-m root zone treatment resulted in greater first-cut timothy DM yield than the 1.00-m root zone treatment at Bow Island. The 0.50-m root zone treatment resulted in greater first-cut timothy DM yield than the 0.25-m root zone treatment at Picture Butte. Treatment effect on the second-cut DM yield was not significant. Water use for the first-cut crop was significantly greater for the 0.25-m root zone treatment at Bow Island and for the 0.50-m root zone treatment at Picture Butte than the other treatments in 2006 and 2007. There was no consistent treatment effect with the second-cut crop water use. The treatment effect with the first-cut WUE was not significant and there was no consistent treatment effect with the second-cut WUE. Use of a shallow root zone depth (0.25-0.50 m) for irrigation management could optimize first-cut timothy production for export, but producers may need to avoid irrigating the second-cut crop to conserve water for other efficient uses in southern Alberta. Key words: Irrigation management, dry matter, timothy, Phleum pretense, root zone, water use efficiency, allowable depletion, available moisture