Effect of irrigation water pH and acidifying source on silvery-thread moss (Bryum argenteum Hedw.) establishment

Many bryophytes are intolerant of osmotic stresses; nevertheless, Bryum argenteum often spreads in golf course greens irrigated with water containing a moderate amount of sodium and/or bicarbonates. The ability of B. argenteum to survive in this stressful environment could be linked to the use of acid injection systems, which are often retrofitted to irrigation systems to combat the negative effects of these harmful salts. The objective of this study was to determine if altering the pH of sodic irrigation water using either sulfuric or hydrochloric acid affects the growth of B. argenteum. Secondarily, if growth of B. argenteum was affected, we sought to understand whether that effect was due to differences in nutrient uptake or availability under the different water pHs and/or acidifying sources. Phosphate buffer solutions (0.01 M, pH = 9) were titrated with each acid to obtain pHs 5, 6, 7 and 8. Irrigation solutions were applied daily to pots containing a sand substrate and nascent B. argenteum for 28 d. Acid source had no effect on moss cover, but pH significantly affected B. argenteum cover. Generally, pots irrigated with pHs 5 and 6 had six to seven-fold increases in B. argenteum cover compared to pHs 7 and 8. Additionally, the shoot tissue of pots treated with pH 5 contained twice as much potassium compared to pots irrigated with pH 9. These results indicate the growth of B. argenteum increases when acid injection systems are used to amend sodic irrigation water.