Evaluation of the Effects of Plastic Mulches - Red, Black, Olive and Control, on the Growth and Yield of Tomato A. A. James, J. A. Sawtelle, and R. W. Griffin College of Agriculture and Human Sciences Prairie View A&M University, Prairie View, Texas Block 3Block 2Block 1 RedOliveControl OliveControlBlack Red ControlRedOlive INTRODUCTION Vegetable production on raised beds with plastic mulch has become the method of choice in many parts of the country. Crops such as muskmelons, tomatoes, peppers, cucumbers, squash, eggplant, watermelons, and okra have shown significant increases in earliness, yield, and fruit quality when grown with plastic mulch. However, in order for plastic mulch to be viable, irrigation is essential. Three major colors of mulch are used commercially: black, clear, and white. Black mulch is used most widely because it retards weed growth, resulting in less chemical usage. Black is popular for cool seasons because it warms the soil by contact, however the clear polyethylene promotes warmer soil temperatures than black mulch. Soils under white mulch or white-on-black mulch remain cooler because less radiant energy is absorbed (Sweat, 2007). Red plastic mulch has been shown to increase tomato yields and quality in some trials and reduce the severity of early blight in others. In addition, it has been shown to significantly increase soil temperatures. SRM-Olive transmits near infra-red radiation, while blocking PAR and still increasing soil temperatures. Therefore, it simultaneously generates almost as much heat as clear mulch and suppresses weeds ( RESULTS AND DISCUSSION Results for 2009 showed that fruit weights were not significantly different for treatments but were significantly different for block x treatment (P < 0.05). Total weights were 26.0, 17.3, 12.1, and 16.2 kg for black, red, olive and control, respectively (Fig. 4). Mean weights were 1.24, 0.91, 0.64 and 0.81 kg for black, red, olive, and control, respectively (Fig. 5). An R 2 of 0.34 and a RMSE of 0.81 kg were obtained. However, comparisons at the 0.05 level were significant between only black and olive treatments. There was a 38% increase in total yield for the black treatment compared to bare ground. Fruits obtained from red and black treatments were observed to be very large and total yields were also higher. Contrary to results from past studies, weed growth was high under the red treatment. Olive and the control treatments succumbed to bacterial wilt (Fig. 7) and blossom end rot. MATERIALS AND METHODS This experiment was conducted at the Prairie View A&M Agriculture Farm. The experimental design was a randomized complete block design consisting of three blocks and four treatments (Fig. 1). Treatments consisted of colored plastic mulches red, black, olive, and the control (bare ground). The crop planted was a vintage heirloom tomato variety – Brandywine Pink. The land was plowed and disked before bed preparation, then compost was incorporated during the land preparation. The colored plastic mulches and drip irrigation lines were installed on April 6 th 2009 and April 21 st 2010 (Fig. 2). Tomato seedlings were transplanted April 8 th 2009 and April 22 nd Seedlings were transplanted into mulched beds 6 m by 1.2 m in rows at spacing of 0.8 m. Each plot contained 7 plants. At planting, a ¼ cup of tomato-tone was placed at the base of the planting hole. In Figure 3, growth under the black plastic mulch is shown. During the course of the experiment, plants were fertigated with liquid fish fertilizer using an E-Z Flow tank. Cages were placed around plants for support in 2009, however, in 2010 T- posts were used because of poor support from cages. During the course of the experiment, a number of seedlings had to be replaced because of wind damage and poor seedling growth. Temperature and soil moisture data were taken between 2:00 and 4:00 pm twice a week during the course of the experiment. Fruits were harvested 2 1/2 months after transplanting and continued for a period of a month. Fruit size and weights were collected and data analyzed using SAS. Fig. 6. Mean Weight for Fig. 1. Plot Design and Layout. CONCLUSIONS Results showed significant differences between black and the other treatments. Although the red treatment produced larger fruits, the mulch effect was negligible. Plants from the olive treatments did not produce high yields, contrary to the documented yield benefits of using olive plastic mulches. Plants grown under olive mulches succumbed to pests and diseases and produced more vegetative growth and less fruits. Yield from the control were the lowest and were significantly affected by weeds. Results suggest that the black plastic mulch produced higher yields and thus would be recommended for the growth of tomatoes. REFERENCES Sweat, M.S Plasticulture Technology for Vegetable Production. Cooerative Extension Service. University of Florida. Orzolek, M.D, and W.J. Lamont Summary and Recommendations for the Use of Mulch Color in Vegetable Production. Department of Horticulture - Center for Plasticulture, The Pennsylvania State University. Fig. 1. Installation of the drip irrigation lines. Fig. 3. Tomato Plants – Black Mulch RESULTS AND DISCUSSION In 2010 fruit weights were significantly different for treatments at p < 0.01 level. However, comparisons were significant at the 0.05 level between the black treatment and all other treatments. Total weights were 26.9, 14.2, 14.1 and 8.3 kg for black, red, olive, and control, respectively (Fig. 4). Mean weights were 1.42, 0.71, and 0.78 and 0.46 kg for black, red, olive, and control, respectively (Fig. 6). An R 2 of 0.27 and a RMSE of 0.81 kg were obtained. When compared to the bare ground control, total yield from the black, red and olive treatment increased 69%, 42%, and 42%, respectively. Total weights were higher for the black treatment in both years. However, total yields for both red and olive treatments were similar, but lower for control. In both years, plants were affected by bacterial wilt, but a larger number were infected in 2010, particularly, bare and olive, thus contributing to lower yields for bare and olive treatments. In past studies, tomato appeared to respond more to red mulch compared to black with an average 12% increase in marketable fruit yield over a 3 year period. However, when environ- mental conditions for plant growth are ideal, tomato response to red mulch is minimal (Orzolek and Lamont, 2008). During the course of the experiment temperature data were recorded. In 2009 average soil temperatures ranged from 17 to 34 0 C and 25 to 40 0 C for Higher temperatures were recorded for the black mulch, a factor which may have resulted in higher weights for this treatment. Fig. 7. Bacterial wilt of tomato. OBJECTIVE To evaluate the effects of three plastic color mulches and control (bare ground) on the growth and yield of an heirloom tomato (Solanum lycopersicum), Brandywine Pink. Fig. 4. Total Yield for all Treatments. Fig. 5. Mean Weight for ACKNOWLEDGEMENTS Special thanks to… Justin Duncan, Greenhouse Manager Steve Hill, Vegetable Plots Coordinator; Farm Worker Prairie View A&M University, College of Agriculture and Human Sciences, Cooperative Agricultural Research Center, Cooperative Extension Program Faculty and Staff