Submitted to: Weed Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/27/2006
Publication Date: 8/1/2006
Citation: Molin, W.T., Boykin, D.L., Hugie, J.A., Ratnayaka, H.H., Sterling, T.M. 2006. Spurred Anoda (Anoda cristata) Interference in Wide Row and Ultra Narrow Row Cotton. Weed Science. 54:651-657. Interpretive Summary: Adoption of new management systems can drastically alter the effects of weeds on crop productivity in that system. The effects competition by the weed spurred anoda on cotton grown in ultra narrow row (UNR) and wide row (WR) cotton production systems was evaluated to determine how these systems respond to weed pressure. This research was performed at SWSRU farm in Stoneville, MS, from 2000 to 2002. The results show that, although there is yield loss with each management system, the yield loss occurs by different mechanisms; a loss in stand with retention of boll load in UNR and a loss of boll load with retention of stand in WR. In the absence of weed pressure yields of WR were significantly greater (23 %) than UNR cotton in 2 of the 3 years. The research shows that these production systems differ in weed response, and each needs to be evaluated independently for its fit into a farmer's crop production and weed control plan.
Technical Abstract: A 3-yr field study was conducted during 2000 through 2002 at Stoneville, MS, to determine the effects of spurred anoda competition on the growth and yields of two cotton species, Delta Pine 5415 (Gossypium hirsutum L.) and Pima S-6 (G. barbadense L.), grown under wide (1 m) (WR) and ultra narrow (0.25 m) row (UNR) cotton management systems. Spurred anoda seed was planted one day after cotton at densities of 0, 6, 24 and 96 spurred anoda per 12 m2 plot. Seed cotton yields and boll number decreased as the spurred anoda density increased for both cotton species and management systems in 2000 and 2002 but not in 2001. WR seed cotton yields for both species, expressed on a per plant basis, decreased as spurred anoda density increased in 2000 and 2002 but not in 2001. Boll weight also decreased as spurred anoda density increased in 2000 and 2002 but not in 2001. Branch biomass decreased as spurred anoda density increased for both species in the wide row management system but not under ultra narrow row system. Thus, the decrease in yield resulting from competition from spurred anoda in WR was due to a reduction in fruiting sites as indicated by a decrease in branch weight. In contrast, cotton density decreased as spurred anoda density increased for both species in the UNR management system but not in the WR system in 2000 and 2002 but not in 2001. Thus, the yield decrease in the UNR management system resulted from a reduction in plant number due to mortality, and the yield per plant, for those plants that survived, remained constant. Unusually high August precipitation in 2001 probably contributed to the lack of spurred anoda effect in 2001.