Effects of Additive to Ease Hard Water Impacts as a Carrier on Glyphosate (Roundup SL 41%) Efficiency and its Effect on Some Growth Parameters of Camelthorn (Alhagi psedoalhagi)

This study was conducted to investigate enhancement effects of additives on efficacy of glyphosate at different levels of water hardness on camelthorn control at Abasabad Research Station (Mashhad) during 2009-2010. Two separate experiments were carried out. In the first experiment، Four doses of glyphosate (Rundup SL %41) i. e. 0، 4، 6 and 8 L. ha-1 were separately tank mixed with 0. 1، 0. 25، 0. 5 percent of X-change at three levels of water hardness including 47. 5، 95 and 190 mgL-1 of Mg+2 + Ca+2. In the second experiment، ammonium sulfate at three levels i. e. 0، 3 and 4 percent replaced X-change while other treatments remained intact. Treatments were applied during early May to camelthorn plants. Each treatment was replicated three times. Results revealed that without applying additives to herbicide solution، glyphosate efficacy to reduce plant height was significantly declined at higher levels of water hardiness as ED50 was increased from 2. 478 to 31. 407 L. ha-1. Maximum glyphosate efficiency was observed when X-change was used with concentration of 5%. It could reduce ED50 to 6. 579 L. ha-1 compared to 31. 407 L. ha-1 where no additive was applied at highest level of hardness. Under low and medium ED50، there was no significant difference between xchange and ammonium sulfate.