Use of Saline Water for Weed Control in Seashore Paspalum (Paspalum Vaginatum) (Report‪)‬

Introduction Turfs are important in human activities from functional, recreational and ornamental standpoints (Beard, 1973), and are characterized by an attractive green colour and a uniform, consistent appearance (Emmons, 2000). Weeds in a turfgrass community, however, disrupt uniformity due to variability in leaf morphology, color, and growth habit. Weeds also compete for light, nutrients, water and physical space, and thus reduce the growth of turf, and can also be a host to other pests (Florkowski and Landry, 2002). Based on relative abundance indices, Cyperus aromaticus L., Fimbristylis dichotoma (L.) Vahl, Desmodium triflorum (L.) DC., Chrysopogon aciculatus (Retz.) Trin. and Borreria repens DC. were the more prevalent and abundant weed species of turfgrass in Peninsular Malaysia (Kamal Uddin et al., 2009). Various management methods such as hand weeding, chemical control, mechanical and cultural practices have been employed to control weeds, but each method has its limitations. Hand-weeding often does not remove below ground rhizomes and tubers, while herbicides are limited in their selectivity. Moreover, the misuse or excessive use of chemicals can cause acute toxicity to humans, contaminate soil and water, and lead to the development of herbicide resistance (Ross and Lembi, 1999). In view of this, alternative methods of weed control have received considerable attention and the possibility of using salt water as an alternative for herbicides has been attempted (Weicko, 2003). Visual observations on the effect of sea water sprays suggest that salt stress could give some control of salt-susceptible weeds in salt-tolerant turfgrasses (Wiecko, 2000). Growth of some weed species was suppressed when irrigated with salt water, while growth of seashore paspalum (Paspalum vaginatum Swartz.) was not affected (Duncan and Carrow 2000; Pool 2005). Raymer (2006) and Duncan and Carrow (1999) reported that seashore paspalum was the most salt tolerant warm-season turfgrass grown in Malaysia. Kamal Uddin et al. (2009) observed 50% shoot and root growth reductions in seashore paspalum at very high salinities of 39.8 and 49.4 [dSm.sup.-1], respectively. The high salinity tolerance of seashore paspalum, thus may allow the use of saltwater for weed control in place of post-emergence herbicides in seashore paspalum turf. Use of salt water as a substitute for herbicides would certainly be beneficial in terms of the impact on mankind and the environment. However, limited information was available on the responses of the local weed flora in Malaysia to saline water treatments. The present is study was therefore carried out to examine the sensitivity of local weed species commonly found in turfgrass to salinity stress under different salt concentrations.