Effect of Rolling on the Lateral Spread of Khakiweed (Alternanthera pungens Kunth)

The dark green color of khakiweed (Alternanthera pungens Kunth) and abundant production of burred seeds interfere with the playability and aesthetic quality of home lawns, golf courses, and athletic fields. In 2009 and 2010, the effect of heavyweight rolling on the lateral spread of khakiweed was investigated in Lubbock, TX. Rolling treatments were conducted using a ride-on roller that applied a static pressure of 0.59 kg cm^-2 at a speed of 1.55 m s^-1. Weekly rolling treatments were: non-compacted – 0 kg cm^-2, low – 7.08 kg cm^-2(4 passes), moderate – 14.16 kg cm^-2 (8 passes), and high – 21.24 kg cm^-2 (12 passes). Khakiweed lateral plant diameters were recorded at trial initiation and every two weeks over a three month period. Hybrid bermudagrass [Cynodon dactylon (L.) Pers. x C. transvaalensis Burtt-Davy] cover was reduced over time in response to high rolling, while cover was maintained in response to low and moderate rolling (personal observation). Statistical differences in lateral plant diameters were not observed until 10 and 12 weeks after initial treatment (WAIT). Non-rolled plots exhibited a 30.1 cm (95% confidence interval of 26.7, 35.6) plant diameter, similar to low rolling (24.4 cm; 95% CI of 22.7, 31.1) but greater than moderate (23.3 cm; 95% CI of 21.7, 29.7) and high (20.4 cm; 95% CI of 18.6, 27) rolling treatments 10 WAIT. At 12 WAIT, high rolling decreased khakiweed plant diameter (19.9 cm; 95% CI of 10.7, 24.7) compared to non-rolled plots (28.8 cm; 95% CI of 20.2, 35.1). Although numerically less than the non-rolled check (28.8 cm), khakiweed plant diameters [(23.5 cm; 95% CI of 14.6, 29.2) and (23.1 cm; 95% CI of 14.8, 27.4)] in response to low and moderate rolling, respectively, were similar. Therefore, khakiweed may proliferate in heavier trafficked areas of golf courses and athletic fields. The combination of cultural and chemical practices may be necessary for the control of this weed.