Study on Effect of Soil Mixture on the Growth of Sports Ground Turf

Sports turf is a relatively weak link in the study of turfgrass science in our country,which is crucial for the development of athletic sports and intercommunications with athletes abroad.Attempting to control the sand,soil and peat content in the root zone,we research into the effect of different sand/soil ratio and peat content on soil physical properties and turfgrass growth.The experiment consists of two one-factor designs: Sand/soil ratio,and peat content.Sand/soil ratio experiment contains 11 treatments,using from 0 to 100 kg·100kg-1 sand/(sand+soil),conducted in the open land.The small plots were constructed within 1×1 m2 polyethylene boxes supported by legged,metal framework.Peat content experiment involves 6 treatments from 0 to 50 g·kg-1,which were conducted in Φ30 cm flowerpots.The main results are as follows: With sand content increasing,total porosity and capillary porosity declined,while air-filled porosity ameliorated.Capillary porosity and air-filled porosity improved notably when sand particle content was more than 80%.After compaction,the porosity in all the treatments reduced,and air-filled porosity declined remarkably when sand content was in the medium.With sand content increasing,saturated hydraulic conductivity increased exponentially.Steady infiltration rate,before turfgrass was planted and two months afterwards,showed the same trend with the saturated hydraulic conductivity,and both have distinct linear relationship.According to the significance of difference,the 11 treatments were divided into three groups: The first group was formed of those with sand/soil ratio from 0 to 3∶7(sand content lower than 60%);the second group contained those with sand/soil ratio from 3∶7 to 7∶3(sand content between 60% and 80%);and the third group consisted of those with sand/soil ratio more than 7∶3(sand content more than 80%).Curves that showed the water characteristics of different sand/soil root zones could be regressed evidently by Power function θ=AS-B.Water retention capability declined gradually,more remarkably at sand content of 60%～70%.According to the appearing sequence of 10-2 level of Cθ,the water supply capability could be divided into three groups: 0～40 kg·100 kg-1 was the strongest,50～80 kg·100 kg-1 was medium,and 90～100 kg·100 kg-1 was the weakest.The relation between soil physical properties and turfgrass growth parameters indicated that aeration and hydraulic conductivity promoted the growth of root with sand content increasing,including root length,root point number,root surface area,root vigor,root biomass and R/T ratio;at the same time,the aboveground growth,including visual quality,height growth,aboveground biomass,and turf clipping was retarded.However,the effect of water retention on the turf growth was contrary to the aeration and hydraulic conductivity.When peat content increasing,total porosity,capillary porosity and air-filled porosity all increased linearly.After compaction,total porosity and capillary porosity still increased with peat content increasing,while air-filled porosity declined,and all porosity were evidently less porous than before the compaction.With peat content increasing,saturated hydraulic conductivity first increased and then declined to the extreme at 20 g·kg-1.After compaction,saturated hydraulic conductivity declined with peat content increasing,causing water retention capability and water supply capability to rise.Both aeration pores and capillary pores extended,which showed that peat could improve the aeration and water retention of the root zone.When soil suction reached 0.5×105 Pa,Cθ of all peat treatments reached to 10-2 level.Root length,root point number,root surface area,root biomass,rhizome,turf density and height,and aboveground biomass increased when peat content rose from 0 to 20 g·kg-1,then declined if the peat content continued to increase.The relation between soil physical properties and turfgrass growth showed that hydraulic conductivity elicits more significant effects on the turfgrass growth than aeration and water retention in the peat experiment.