Suppression of Purple Nutsedge (Cyperus rotundus) with Polyethylene Film Mulch

In greenhouse experiments, translucent polyethylene film mulches reduced or eliminated purple nutsedge shoot emergence compared to a conventional, opaque, white/black polyethylene film mulch. The translucent mulches 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 mulch as well as opaque mulch. Shoots emerging in pots illuminated by a mixture of fluorescent and incandescent lighting failed to penetrate translucent 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 translucent mulches elevated soil and air space temperatures 4–13 C compared to opaque mulch. However, in the growth chamber experiment, air space temperatures 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 mulch cannot be attributed to solarization effects.