(224) Weed Control in Norway Spruce Christmas Trees with Applied Films

Abstract

Weed management systems for Norway spruce (Picea abies L.) Christmas trees were investigated under field conditions. Potential alternative methods to replace the use of herbicides included the application of three different soil covers: plastic film (100% recoverable), biodegradable film 40-μ thick, and biodegradable film 70-μ thick. On another group, weed control was carried out mechanically (control plants). Each treatment consisted of 27 plants with three replications. At the time of the first growing season, the percentage of dead and survived plants in treated plants and in the control plants did not differ significantly. Data were recorded on plant height and quality during the second year of growth. Control plants always showed height increases shorter than other plants. Application of these films significantly affected growth and plant quality. In plastic film-treated plants, the average height increases were significantly higher than those observed on control plants mechanically treated (19 vs. 12 cm, respectively), and did not differ from biodegradable film-treated plants (17 cm). Plants responded similarly to the biodegradable films of varying thickness. The results indicate that all three films have potential for use in Christmas tree production. However, the use of biodegradable films would be preferable because they do not need to be removed at the end of the rotation (about 6–7 years). Furthermore, this culture system would be an efficient way to achieve three objectives: 1) to enhance weed control, avoiding the application of herbicides by many Christmas tree producers; 2) to improve quality and plant commercial value; and 3) to obtain a shorter rotation.