Hydraulic conductivityof golf course putting green root zones affected bysodium adsorption ratio of leachingwater

ZHANG Hua;WANG Yi-chun;LI De-ying;School of Applied Chemistry and Biological Technology,Shenzhen Polytechnic;Department of Plant Sciences,North Dakota State University;

golf course;;putting green;;root zone;;saturated water conductivity;;salinity;;leaching.

Soil salinization is a major problem threatening turfgrass management.Alternative water sources such as recycled water(RW)usually have elevated salt content.With high exchangeable sodium in soil,rain or irrigation with fresh water can cause soil dispersion,and thus reduce water infiltration and permeability.The objective of this study was to determine the effect of salt composition in irrigation water on saturated water conductivity(Ksat)of putting green root zone materials and constructions.Three root zone materials,clay(Fargo,North Dakota,USA),clay loam(Garick Corp.,Cleveland,OH),and sand/peat mixture(Dakota Peat,North Dakota,USA)(90/10v/v)were tested alone,as well as tested in different root zone construction,i.e.soil pushup green(40cm deep),sand/peat mixtures in USGA-putting green style(30cm of root zone over 10cm gravel)and California putting green style(40cm deep).Saturated water conductivity was determined after the root zone materials and construction were leached with water of five levels of SARw(0,2.5,5.0,15.0,and∞).All except the SARw0had an ECw of 11.0dS/m.The results showed severe soil dispersion may happen when SARwof leaching water is greater 5for clay and clay loam.A laboratory test may predict the severity of dispersion but further study is needed to quantify the effect of soil organic matter(OM)and clay mineralogy.Generally,sand/peat mixtures used in root zones of either California or USGA putting green style is not vulnerable to dispersion by salt in irrigation water.