Plastic Mulch Color Inconsistently Affects Yield and Earliness of Tomato

Abstract

“ Table 1. Plastic mulch color effects on yield and early harvest of tomatoes. The surface color of plastic mulch can change the quantity of light and spectral balance reaching plants, with resulting effects on growth and fruit production (Decoteau et al., 1986, 1988, 1989). In their work with tomatoes (Lycopersicon esculentum Mill.), plants grown over red mulch had the highest early marketable yields and produced the least amount of foliage, while plants grown over white or silver-colored mulch had lower early marketable yields but produced more foliage. Since this research showed that mulch surface color may affect tomato production, we designed an experiment aimed to corroborate their results in another location and to expand the range of plastic mulch colors evaluated. Field plots evaluating mulch color effects on fresh-market tomatoes were established at the E.V. Smith Research Center of Auburn Univ. in east-central Alabama in 1990. The soil was an Orangeburg sandy loam, a fineloamy siliceous thermic Typic Kandiudult. Lime and fertilizer were broadcast before planting and disked into the top 0.2 m of soil at rates determined by soil test recommendations for tomatoes (Cope et al., 1980). Mulch treatments consisted of a bare soil unmulched control and seven colors of plastic mulch. For mulches where colors were obtained by painting, paints specified were diluted 2:1 with mineral spirits paint thinner and were sprayed onto standard black film (Edison Plastics Co., Washington, Ga.). The films listed, unless noted, were 31.5 μm thick. Green: IRT-76 green wavelength-selective film (AEP Industries, Bonita Springs, Fla.). Aluminum: Painted with “aluminum 32” polyurethane oil enamel paint (Thompson and Formby, Memphis, Tenn.). Red: Painted with Chinese red 15” polyurethane oil enamel paint (Thompson and Formby). Brown: 20.3-