SUPPRESSION OF PURPLE NUTSEDGE (CYPERUS-ROTUNDUS) WITH POLYETHYLENE FILM MULCH

In greenhouse experiments, translucent polyethylene film mulches reduc ed or eliminated purple nutsedge shoot emergence compared to a convent ional, opaque, white/black polyethylene film mulch, The translucent mu lches reduced purple nutsedge shoot biomass, tuber and rhizome number, and tuber biomass 85-99%. In a nonilluminated growth chamber, purple nutsedge shoots emerging from tubers readily penetrated translucent mu lch as well as opaque mulch. Shoots emerging in pots illuminated by a mixture of fluorescent and incandescent lighting failed to penetrate t ranslucent mulch but penetrated the opaque mulch. In field experiments , translucent mulches reduced emergence and growth of purple nutsedge 70-88% compared to opaque mulch, Numbers of viable tubers in the soil were reduced 65-76%, In greenhouse and field experiments, the transluc ent mulches elevated soil and air space temperatures 4-13 C compared t o opaque mulch. However in the growth chamber experiment, air space te mperatures were not affected by mulch type, and soil temperatures were only 0.4-0.6 C higher under the translucent mulches. Results suggest that the suppression of nutsedge emergence and growth by translucent m ulch cannot be attributed to solarization effects.