Control of Arborescent Vegetation below Power Lines with Wastewater Sludge
- Yvon Grenier and
- Denis Couillard *
A 1-yr field study was conducted to determine whether fertilization with wastewater sludge could favor growth of herbaceous and shrub species to inhibit or eliminate the growth of tree species under power lines. Results show that a significant proportion of the trees died: mortality ranged from 35 to 100% on plots that received 160 Mg ha−1 of sludge, and ranged from 0 to 31% on control plots. The surviving trees showed accelerated growth. Means of height increments ranged from 17 to 86 cm on plots receiving 80 Mg ha−1 of sludge, and ranged from 5 to 31 cm on control plots. Sludge applications also decreased regeneration success of trees in the current year, with a minimum of 0.8 and a maximum of 7.0 new seedlings per 12.5 m2 on treated plots, as compared to 14.0 new seedlings on control plots. With the short duration of this preliminary study, it is concluded that the herb and shrub strata did not have sufficient time to fully develop in a single growing season and that the hypothesis remains to be verified.
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