Effects of artificial shading and plant density on Corymbia citriodora seedling characteristics

Abstract

In forestry, alternative seedling production systems that lead to increased growth rates and efficiency in natural resource use are needed. The objective of this work was to evaluate the influence of colored shade mesh and plant density on dry biomass, leaf area index, chlorophyll content, and radiation use efficiency of C. citriodora seedlings. The study was conducted in a greenhouse at the Federal University of Santa Maria, campus Frederico Westphalen-RS. The experimental design was completely randomized and arranged in a 2 x 3 factorial scheme with two plant densities (high density, 402 plants/m² and medium density, 201 plants/m²) and three shade conditions (red or blue mesh with 30% solar radiation restriction or no mesh). The variables evaluated were dry biomass, leaf area index, chlorophyll content (a, b, and total), radiation use efficiency, and solar radiation interception. The use of colored shade mesh and plant density appears to alter microclimate conditions, affecting the efficiency of radiation use and dry biomass of C. citriodora seedlings. The leaf area index, however, is affected only by plant density. For seedling production, the red mesh provided the most similar results to the treatment without mesh. Additionally, high plant density yielded the best results for dry biomass and leaf area index for all shade treatments