Study On Optimization Of Rootzone Mixture For Golf Putting Green

Evaluating the effects of putting green rootzone mixtures on soil physical properties and the turfgrass performance is of great immediate significance to golf course construction.Using methods of canonical correlation and regression analysis,the significantly correlative models between soil physical properties and creeping bentgrass performances and the rootzone mix component were established with 13 golf green rootzone mixtures when varying in particle size distribution and peat ratio.The qualitative and quantitative relationship between the dependent and independent variables were determined.The optimal mix scheme was acquired according to the USGA recommendations.The main results were as follows:The water retention was significantly different among 13 rootzone mixtures.The regression model of Water characteristic curves wasθ=AS^-B.The impact of 3 kinds of golf green profile(1-layer,2-layer,and 3-layer) on the hydraulic properties of 13 rootzone mixtures was evaluated.The mixtures had significantly much more water content with depth in 1-layer profile than that in other two profiles.There was significantly more water content with depth in 2-layer profile for 7 mixtures(G-M) with high peat ratio(＞5%),but there was no significantly more water content with depth for pure sand mixtures(A-E) and mixture(F)with low peat ratio than that in 3-layer profile.The saturated hydraulic conductivity had been increased significantly after passing the mixed soil through 0.05mm sieve.And this could make those mixtures with their physical properties didn't conform to the USGA specification be up to USGA requirements.The physical properties and turfgrass performance were significantly different among 13 rootzone mixtures.The total water content and capillary porosity were mainly influenced by peat and very fine sand plus silt and clay.Bulk density and total porosity were mainly influenced by mid-coarse sand and peat.The order to influence K_sat was fine sand,mid-coarse sand,peat,and very fine sand plus silt and clay.Exception of mid-coarse sand,the other 3 independent variables was main factors to influence turf establishment,so was the visual turf quality in Jun.But the visual turf quality in November was mainly related with middle-coarse and fine sand.Fine,very fine sand plus silt and clay had main effects on clippings.Above-ground biomass in Jun was only influenced by peat.Under-ground biomass in November was mainly influenced by peat and very fine sand plus silt and clay.The green-up was related with all of 4 independent variables,but mainly influenced by very fine sand plus silt and clay.The optimal mix scheme with all of the physical properties conformed to the USGA recommendations from significantly correlative regression model was acquired.If suitable profile was selected or passing through 0.05mm sieve,the quantity range of mix component could be widen significantly.It suggests in this study that refinement of recommendations is warranted.