Impact of regular mowing, mowing height, and grass competition on tuber number and tuber size of yellow nutsedge clonal populations (Cyperus esculentus L.)

Abstract

Cyperus esculentus, a perennial sedge, is one of the most dangerous weeds in agriculture because of its high multiplication potential, its high risk of tuber spread and its low sensitivity to control measures. To diminish the risk of C. esculentus spread and incursion into adjacent crops by creeping rhizomes, control measures should also focus on non‐cropped areas adjacent to these crop zones. Defoliation by mowing is an example of one of these control measures. The aim of this study was to identify the critical mowing interval and height required for preventing tuber formation and to assess the combined effect of mowing and competition exerted by the grassy vegetation on the growth and spread of C. esculentus in field margins. In two separate years we conducted an indoor container (11 L) experiment, under a worst‐case scenario, in which genetically distinct clones, grown alone or in combination with Lolium perenne, were subjected to season‐long mowing regimes that differed in mowing interval (1‐, 2‐, 4‐ and 8‐weeks) and/or mowing height (2 and 5 cm). Weekly and 2‐weekly mowing at 5 cm within an 18‐week period significantly reduced tuber production of C. esculentus grown with competition (up to 93% and 98% reduction in tuber number respectively) and without competition from L. perenne (both a 97% reduction), compared to the uncut control with and without competition respectively. Compared to a mowing height of 5 cm, a mowing height of 2 cm resulted in better control of C. esculentus, with tuber numbers up to 32% lower and 5–65% lighter. Twice‐weekly mowing at 2 cm height can be an effective strategy for containing or reducing C. esculentus patches in field margins.