Potential effects of diurnally alternating temperatures and solarization on purple nutsedge (Cyperus rotundus) tuber sprouting

Purple nutsedge (Cyperus rotundus L.) is one of the most serious weed problems of the arid environments. The distribution of its tubers in a naturally infested field in Greece indicated that the highest proportion is located in the upper 200 mm of the soil. Furthermore, the effects of temperature alternation on the rate and percentage of tuber sprouting were evaluated by means of laboratory studies. It was found that the total tuber sprouting and rate were significantly increased after a shift of daily temperature fluctuation from 0 to 12 °C. Sprouting rate and percentage were significantly and consistently higher for the tubers originating from the upper 5 cm of the soil, compared with the tubers obtained from the layer of 50-150 mm for all the temperature treatments. Additionally, solarization seems potentially effective on purple nutsedge tuber sprouting, as long as it resulted not only to a soil temperature shift, but also to a high diurnal temperature variation. Moreover, the uniform sprouting of about 95% of the tubers in the soil may allow a more complete control by mechanical, biological or chemical methods.