Yellow Nutsedge (Cyperus esculentus) Interference in Simulated Sweetpotato (Ipomoea batatas) Plant Beds

Greenhouse experiments were conducted in 2016 at Pontotoc and Verona, MS. On March 3 (Pontotoc) and March 7 (Verona), landscape fabric was placed in the bottom of polyethylene lugs, each 0.22 m2, then approximately 5 cm of a 1:1 (v/v) blend of soilless potting media and masonry sand was added. ‘Beauregard’ sweetpotato [Ipomoea batatas (L). Lam.] storage roots weighing between 85 and 227 g, and several with emerging sprouts ≤1 cm, were placed longitudinally in a single layer on the substrate, then covered with an additional 3 cm of the substrate. Sprouted yellow nutsedge (Cyperus esculentus L.) tubers were transplanted equidistantly into sweetpotato-containing lugs at six densities: 0, 18, 36, 73, 109, and 145 m−2. Trials were terminated 55 and 60 d after planting at Pontotoc and Verona, respectively. Predicted total sweetpotato stem cuttings (slips) decreased linearly from 399 to 312 m−2 as C. esculentus density increased from 0 to 145 m−2. Predicted total slip dry weight at a C. esculentus density of 145 m−2 was reduced 21% compared with 0 m−2. Predicted rotten sweetpotato storage roots increased from 2.6 to 11.3 m−2 as C. esculentus density increased from 0 to 145 m−2. In response to increasing C. esculentus density, sweetpotato seed roots exhibited increased proximal-end dominance.