Can We Reduce Salinity Effects by the Application of Humic Acid on Native Turfgrasses in order to Attain Sustainable Landscape?

Soil salinity is one of the most important problems in arid and semiarid climate areas of the world. So, we investigated the effects of humic acid on visual quality and quantity parameters of native turfgrasses in compared to commercial variety under salinity stress to explore can we reduce salinity effects by humic acid or not? So, a research was arranged in factorial experiment based on a randomized complete design with three replications. The first factor was three grasses consisted of two native accessions of Lolium perenne ҅Chadeganʼ and ҅Yarandʼ and its commercial variety, the second factor was four concentrations of humic acid (HA) (0, 5, 10, 15 g kg-1) and the third factor consisted of three levels of salinity (0, 150, 300 mM). Results of analysis of variance indicated that the interaction effects of cultivar × HA was significant in all traits (P<0.01) except on uniformity and plant height. The treatment of cultivar × salinity significantly affected color, texture, smoothness, uniformity and RWC (P<0.01) and total quality (P<0.05). Treatment of HA × salinity had not significant influence on smoothness and uniformity but other traits were significantly influenced (p< 0.05) and RWC (P<0.01). Also, triple interaction effect was significant on texture, quality after clipping, uniformity and RWC (P<0.01) and plant height (P<0.05). Application of HA could decreased salinity effect on darkness, texture and increased quality after clipping and relative water content of leaves under salinity stress. Also, increasing of severity of salinity had reduction effect on plant height and total quality even with HA application. In other hands, plants grow on soils which contain adequate humic acids (HA) are less subject to stress condition, are healthier because of having higher relative water content in compared to salinity condition.