Effects Of Different Treatments On Spring Conversion Of Overseeding Turf

To solve the difficult problem of getting cool-season turfgrass properly transitioned to warm-season turfgrass in spring for overseeded turf in Hunan area,different concentration of Monument,different mowing height and different vertical cut times were foliar sprayed in a Zoysia japonica‘Lantai No.3’lawn overseeded with ryegrass to inhibit the overgrowth of ryegrass and to create conditions for the regrowth of zoysiagrass.The main findings are as follows:The NDVI index and green index increased after different height mowing in the overseeded turf.The MDA content and electrolyte leakage gradually increased in Panterra,while the turf density increased in zoysiagrass.The treatment of B1（3cm mowing height）promoted spring transition of the turf grass in 50 days to achieve the best performance.Only the treatment of A2（2cm mowing height）had a better effect and completed in June 8^thfor Monterey,but the time of transition was too long and Monterey was not completely dead.The treatment of B1（2 times vertical cut）promoted the NDVI index and green index increased after different height mowing in the overseeded turf.The MDA content and electrolyte leakage gradually increased in Panterra,while the turf density increased in zoysiagrass.The overseeded turf complete spring conversion in 75 days.But no treatment complete spring transition in June 30^thof Monterey,the 3 treatment groups were all poor.The results showed that the NDVI index and green index firstly decreased and then increased after foliar application of Monument in the overseeded turf.The MDA content and electrolyte leakage gradually increased,while the turf density declined in ryegrass and increased in zoysiagrass after foliar application of Monument in the overseeded turf.The appropriate spraying concentration was 3×10^-22 mL?m^-22 for the two ryegrass cultivars.It takes 45 days to completely transitioned for Panterra and it takes 60 days to completely transitioned for Monterey under this appropriate spraying concentration.The comprehensive analysis shows that spraying concentration Monument with 3×10^-2mL/m²,3cm mowing height and 2 times vertical cut all can effectively promote Lolium multiflorum Lam.（Panterra）spring transition,and it takes 45 days,75 days and 50 days to completely transitioned.Mowing and vertical cut could play apromoing role in spring transition of Lolium perenne L.（Monterey）,but the risk is big.the most effective way for the spring conversion of Monterey is to spray concentration Monument with 3×10^-2mL/m²,and it takes 60 days to completely transitioned.