David L. Coffey and Jimmy R. Summerlin Jr.

Plasticulture studies were continued on bell pepper. Total marketable fruit yields of 4.85, 3.94 and 3.09 tons per acre were obtained from plants grown on silver, white, and black plastic mulches, respectively. Number of fruits produced per plant followed the same trend. Individual fruit weights of 85-117g were not significantly different among treatments. Fruit set as indicated by number of fruits too small to be of marketable size at termination of the experiment were significantly greater from plants grown on silver mulch. Later in the growing season, weed competition was very detrimental in this study, especially in a conventional, no plastic treatment.

Research involving plasticulture technology was continued at The University of Tennessee Knoxville Experiment Station in 2001 to determine means to increase the yield and quality of bell peppers. Higher yields of larger, better grade-out fruits than are currently achieved by most growers of bell peppers for the fresh market are needed for growers to maximize their returns from the production of this crop.

Materials and Methods

Field plots were established in a randomized complete block design with four replications. Mulches evaluated were the three plastic colors, silver, white and black, and a bare ground check. Rows were 27 ft long on 7 ft centers and were equipped with trickle irrigation. Seeds of the cultivar ‘Camelot’ were planted on April 1, 2001 and transplanted on May 14, 2001. Transplanting occurred in staggered double rows with rows and plants spaced 18 in. apart on the plastic with 50 plants per plot. Transplants received a drench application of Terrachlor for disease control. Plots were fertilized with a broadcast application 500 lbs/a 10-10-10 prior to transplanting. Plots were fertigated weekly beginning June 01, 2001 and continuing until final pepper harvest with alternate applications of CaNO3, KNO3, and NH₄NO₃. Bare ground plots were hand weeded before first harvest. Fruits were harvested four times beginning July 16 and ending July 30. Because of extreme weed competition in these plots, this experiment was terminated early. All data were analyzed by ANOVA methods and means of significant treatment differences were separated using Duncan’s Multiple Range Test at the 0.05 level of probability.

Results and Discussion

Fruit size and yields were influenced by the plastic mulch. Although both fruit size and yields from this study were somewhat less than desirable for commercial production, the influence of plasticulture compared to conventional, bare ground production is quite evident. Season long weed control is a problem under both conventional and plasticulture production, less severe under plasticulture as in-row competition is reduced from the.presence of the plastic mulch. Among the three colored plastics compared, marketable fruit numbers and yields were slightly greater from the silver and white than from the black. This is quite obvious when considering the total number of fruits. As indicated in the materials and methods section of this report, this experiment was terminated earlier than would have been typical for commercial production, thus at the termination of the experiment many of the fruits that were graded in the cull category are there because of small size. These fruits would have sized up into marketable sized fruits if the experiment had continued. These results suggest that the fruit set from the more reflective, thus cooler, silver and white colored mulches may have resulted in greater fruit set during this hotter part of the growing season. Results from 2001 studies also reflected this trend.

Table 1. Numbers and marketable percentages of bell peppers fruits from plants grown oncolored plastic mulch at The University of Tennessee Knoxville Experiment Station, 2001.

Table2 Individual ant total marketable weights of bell peppers fruits from plants grown on colored plastic mulch at The University of Tennessee Knoxville Experiment Station, 2001.

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This research represents one season's data and does not constitute recommendations.  After sufficient data is collected over the appropriate number of seasons, final recommendations will be made through research and extension publications.