Effects of “lights out” turfgrass renovation on plants, soil arthropod and nematode communities

“Lights out” turfgrass renovation approach is a pesticide-free method of weed and pest management that can reduce weed pressure when replanting turf, switching grass types, or completing a total renovation of a designated grassy area. In this study, we addressed the feasibility of using black, geo-textile weed mats made of woven polypropylene plastic in this alternative turfgrass renovation approach. The specific objectives were: 1) to determine the most effective weed mat density to suppress weeds; 2) to determine the most effective fertilizer treatment (fertilizer × rate) to stimulate weed seed germination and drain the weed seed bank; and 3) to document changes in the biotic communities in the soil including nematodes and insects. This research was conducted in 2016 at Magoon Research Facility on the island of Oahu, Hawai'i. Our results indicated that the “lights out” method was effective, with all cover types providing better weed suppression than control plots treated with glyphosate. There were no significant differences between fertilizer treatments for weed diversity or coverage percent one-month post-fertilization. However, all plots treated with fertilizer had significantly less weed diversity and coverage after the Bermudagrass was planted, indicating that fertilization plays a crucial role in draining the weed seed bank. Soil arthropod and nematode communities were generally altered after each renovation step, indicating that covering and fertilization play a role in shaping the diversity, abundance, and maturity of the soil food web.