Effects of the planting substratum on the growth of horseweed (Conyza sumatrensis (Retz.) Walker) in Zoysia japonica Steud. turf

Abstract

AbstractTo explore the extent to which turfgrass–weed competition may be modified by the planting substratum, turfs of Zoysia japonica Steud. were established in pots containing four different materials: granitic sand, sandy loam, granular volcanic clay and waste concrete debris. Seedlings of horseweed (Conyza sumatrensis (Retz.) Walker) were later transplanted into the turfs growing in these pots. After 7 months of growth in competition, the biomasses of both turfgrass and weed were greatest on sandy loam. The proportion of weed biomass in the total plant biomass was also largest on sandy loam (28.4%), suggesting that high nutrient levels may enhance weed encroachment in Zoysia turf. Granular volcanic clay suppressed weed biomass to a low proportion of total biomass (5.8%) while supporting turfgrass growth equivalent to that on sandy loam.