Soil solarization, also referred to as solar heating or solar pasteurization, is accomplished by passive heating of moist soil covered with transparent plastic film for more than 6 weeks ( McGovern and McSorley, 1997 ). Solarization is a useful
physiology. Photoselective plastic films, bagging, mulch, coating, or netting can be used to alter light. Far red (FR) and red lights (R), and the ratio of FR/R photon can be significantly affected by these applications, which might act through the natural
; and Green-Tek and Sonoco for plastic film mulches. Mention of trade names in this publication does not imply endorsement by the Univ. of Georgia of products named, nor criticism of similar ones not mentioned.
tomato seeds; United Irrigation and Roberts Irrigation Products Inc., for drip tape; Hydro Agri North America, Inc., for calcium nitrate liquid fertilizer; and Green-Tek and Sonoco for plastic film mulches. Mention of trade names in this publication does
calcium nitrate liquid fertilizer; and Green-Tek and Sonoco for plastic film mulches. Mention of trade names in this publication does not imply endorsement by the University of Georgia of products named, nor criticism of similar ones not mentioned.
years, vegetable production has shown significant yield increases [ Krug, 1999 ; U.S. Department of Agriculture (USDA), 2007 ]. Plasticulture techniques such as plastic film mulch and drip irrigation have undoubtedly contributed considerably to these
study was to examine the effect of an aluminized plastic film (APF) and a particle-based reflective film applied to the tree (PFT and PFW) and the grass (RPF) between tree rows, each with different R/FR reflection characteristics, on apple color and
Plant response to photoselective plastic films with varying spectral transmission properties was tested using lisianthus (Eustoma grandiflorum) `Florida Pink', `Florida Blue', and `Florida Sky Blue'. Films were designated YXE-10 (far-red light-absorbing film) and SXE-4 (red light absorbing film). Light transmitted through YXE-10 films reduced plant height compared to control plants by 10% (`Florida Blue'), and stem dry weight by 19% to 40%, but the response varied by cultivar. Internode length was reduced by 10% to 19% when `Florida Pink' and `Florida Sky Blue' plants were grown under YXE-10 films. Leaf and root dry weights were not affected by YXE-10 films, with the exception that `Florida Sky Blue' plants had a lower leaf dry weight than the control plants. Light transmitted through SXE-4 films increased plant height of `Florida Pink' plants by 15% but not of `Florida Blue' or `Florida Sky Blue.' Regardless of cultivar, dry weight of leaf, stem and root tissue was not affected by SXE-4 films as compared to control films. The average number of days to flower and bud number were not affected by YXE-10 or SXE-4 films, regardless of cultivar. The results suggest that selective reduction of far-red wavelengths from sunlight may be an alternative technique for greenhouse production of compact plants, but the magnitude of the response is cultivar specific.
Ultraviolet (UV)-absorbing plastic films are being used as a photoselective barrier to control insect vectors and associated virus diseases in different horticultural crops. A 2-year experiment was carried out in northeastern Spain (Navarra) to evaluate the impact of a UV-blocking film (AD-IR AV) on the population density of insect pests and the spread of insect-transmitted virus diseases associated with head lettuce [Lactuca sativa (L.)]. Results showed that the UV-absorbing plastic film did not loose its ability to filter UV radiation after three lettuce crop cycles (14 months). The UV-absorbing plastic film was effective in reducing the abundance and in delaying the colonization of lettuce by aphids [Macrosiphum euphorbiae (Thomas) and Acyrthosiphum lactucae (Passerini)]. A significant increase in the percentage of marketable plants was achieved under UV-absorbing films due to a reduction in the number of plants infested by aphids and by insect-transmitted virus diseases (mainly potyviruses). Also the UV-absorbing plastic films were effective in reducing the population density of Frankliniella occidentalis (Pergande) and the spread of tomato spotted wilt virus (TSWV) as well as the population density of the lepidopteran pest, Autographa gamma (L.), a common pest of lettuce in Spain. However, no effective control of the greenhouse whitefly Trialeurodes vaporariorum (Westwood) was achieved. The results showed that UV-absorbing plastic films are a very promising tool to protect greenhouse lettuce from the main pests and insect-transmitted virus diseases occurring in northeastern Spain.
Growth and development responses of three chrysanthemum [Dendranthema ×grandiflora (Ramat.) Kitam. (syn. Chrysanthemum ×morifolium Ramat.)] cultivars (`Bright Golden Anne', `Iridon', and `Yellow Snowdon') to photoselective plastic films with varying concentrations (0 to 0.22 g·m-2) of a far-red (FR) light absorbing dye were investigated under greenhouse conditions. Photoselective films reduced stem elongation of all three cultivars. The greater the dye concentration in the film, the greater and earlier the reduction in stem elongation. After 4 weeks, `Yellow Snowden', `Bright Golden Anne', and `Iridon' plants grown under the film with the highest dye concentration (Afr3 film) were 21%, 26%, and 26% shorter than control plants, respectively. Height reduction under photoselective films was caused by shorter internodes. Photoselective covers were most effective in reducing the stem elongation during the early vegetative period. Following transition to the reproductive stage, weekly stem elongation rates were reduced. At the time of flowering, `Yellow Snowden', `Bright Golden Anne', and `Iridon' plants grown under the film with the highest dye concentration (Afr3 film) were 12%, 7%, and 14% short9er than control plants, respectively. Photoselective covers did not affect the anthesis of chrysanthemum cultivars, but resulted in a 10% to 14% reduction in flower diameter depending on the cultivar. Although the films with higher dye concentration were more effective in reducing stem elongation of chrysanthemum, increased dye concentration reduced light transmission. Thus, photoselective covers that reduce light transmission over 25% would not be suitable for commercial production.