Regrowth of Lowland Ecotype Cyperus rotundus L. in Response to Soil Depth, Shoot Clipping and Flooding Depth Interventions

Abstract

Lowland ecotype Cyperus rotundus L. (LE-CYPRO) has tubers that can grow and survive under flooded conditions. However, information on the responses of its tubers to the combination of soil depth or shoot clipping with flooding is unavailable. Two experiments were conducted to determine the germination and regrowth of LE-CYPRO tubers in response to soil depth, shoot clipping and flooding depth interventions. Experiment 1 involved pre-sprouted (PS) and non-sprouted (NS) tubers subjected to three soil depths (0, 5 and 10 cm) and three flooding depths (0, 3 and 5 cm); Experiment 2 used PS tubers subjected to shoot clipping at periods of 10, 20 and 30 days after planting (DAP) under three water conditions (saturated, early flooding and late flooding). Irrespective of soil depths, PS and NS tubers had 100% germination and regrowth without flooding (0-cm flooding depth). When planted at the soil surface (0-cm soil depth) and flooded by 3- to 5-cm, only 50 and 40% of PS while 20% of NS tubers germinated. No germination was seen on tubers buried under 5- to 10-cm soil depths and flooded by 3- to 5-cm depths. Revived PS tubers buried and flooded for 100 days at 0-, 5- and 10-cm depths had 20 to 60% germinations at 3-cm flooding depth and 20 to 70% at 5-cm flooding depth; NS tubers had 40 to 50% germinations at 3-cm flooding depth and 40% at 5-cm flooding depth. Growth variables of the weed at shoot clipping periods of 10, 20 and 30 DAP were comparable to the control under saturated conditions. Growth variables were reduced by 68 to 97.3% and 21.7 to 100% when aided by early and late flooding, respectively. This information could be used in the formulation of effective and comprehensive weed management for LE-CYPRO.