Title: Effects of shoot clipping-soil disturbance frequency and tuber size on above-and below-ground growth of purple and yellow nutsedge
Abstract: Purple and yellow nutsedge are two of the world's worst weeds, reproducing asexually by rhizomes that can develop into new shoots or tubers. These tubers are the storage organs for carbohydrate reserves that are replenished by growing shoots and exhausted by new shoot, root plus rhizome, and bulb production. Based on the biology of both species, we hypothesized that the regenerative potential of purple and yellow nutsedge will decrease with increasing shoot clipping-soil disturbance (SCSD) frequency and decreasing tuber size. To test this hypothesis, experiments were conducted to determine the effect of SCSD frequency and tuber size on above- and below-ground growth of purple and yellow nutsedge. Five viable tubers of two tuber category sizes (small: 0.40 ± 0.05 g and large: 0.80 ± 0.05 g per tuber fresh weight) were subjected to four SCSD frequencies (weekly, biweekly, monthly, and none) for 12 wk. SCSD was performed by clipping the emerged nutsedge shoots followed by manually disturbing the soil. SCSD at biweekly or weekly intervals reduced purple nutsedge proliferation, regardless of initial tuber size. However, monthly SCSD did not suppress purple nutsedge as effectively as weekly or biweekly SCSD, and less proliferation occurred with small tubers than large tubers. In contrast, yellow nutsedge proliferation was equally reduced with monthly or more frequent SCSD, regardless of initial tuber size. Even weekly soil disturbance for 12 wk failed to eradicate all small or large tubers in either species. Thus, yellow nutsedge is managed more easily than purple nutsedge with less frequent tillage or cultivation. However, tillage or cultivation alone over a 12-wk period will not likely eradicate either nutsedge species from infested soil. [Sanjeev Bangarwa, Jason K. Norsworthy & Edward Gbur (2012).Effects of shoot clipping-soil disturbance frequency and tuber size on above-and below-ground growth of purple and yellow nutsedge. Weed Technology, online 11 July 2012. doi: dx.doi.org/10.1614/WT-D-12-00041.1] ${imageDescription} Comment