EXTENSION DEMONSTRATION AND RESEARCH REPORT COOPERATIVE EXTENSION SERVICE UNIVERSITY OF ALASKA FAIRBANKS FAIRBANKS, ALASKA

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1 1991 EXTENSION DEMONSTRATION AND RESEARCH REPORT COOPERATIVE EXTENSION SERVICE UNIVERSITY OF ALASKA FAIRBANKS FAIRBANKS, ALASKA February, 1992 Printed on recycled paper with soy ink

2 PRODUCING VEGETABLES USING INFRARED TRANSMITTING PLASTIC MULCH AND PERFORATED ROW COVERS by Jerry Purser, Agricultural Development Agent Andrea Robb, Agricultural Assistant Willy Welch, Agricultural Assistant COOPERATORS: LOCATION: FUNDING SOURCES: OBJECTIVES: Pyrah's Pioneer Peak Farm, Ted & Preston Pyrah Gold Nugget Farm, Paula Giaque Pioneer Peak Farm, Bodenberg Loop Road, Palmer, Alaska Alaska Science and Technology Foundation, Tennessee Valley Authority, and Polyon West 1, To demonstrate the advantages of using infrared transmitting (IRT) plastic mulch and perforated row covers in producing vegetables. 2. To develop an enterprise budget of costs and returns when using plastic mulch and row covers in the production of vegetables. (To be completed in 1992.) METHODS: The trial site was disked and broadcast fertilized with Ib/a of nitrogen (N), phosphate (PaOs), and potash (KaO), respectively, on 5/8/91. The site was then rototilled to a depth of 4 in. The IRT plastic mulch and drip irrigation lines were laid simultaneously using a mechanical mulch layer on 5/16-17/91. Rows were 80 in apart and 400 ft in length. The wide row spacing was required to accommodate the mechanical tunnel layer and hoop setter. Holes were cut through the IRT plastic mulch with a bulb planter to allow the planting of vegetable transplants. The corn and beans were seeded in the row using a Seedway garden planter prior to the application of plastic mulch. All other vegetables in the trial were planted as transplants raised by Paula Giaque of Gold Nugget Farm. The transplants were planted at the 2 true leaf stage of growth. Table 1 lists the crops grown, row length, and spacing of seeds and transplants. 11

3 Table 1. Row Length, Seed and Transplant Spacing and Date of Planting for Vegetables Grown in Plastic Mulch Trial. Vegetable Crop Cultivar Planted Row Length..ft- Transplant/ Seed Spacing in Date Planted Snap Beans Cucumber Zucchini Squash Pumpkins Summer Squash Scallopini Squash Novelty Squash Butter Cup Squash Acorn Squash Butternut Squash Provider Polar Vee Precocious Slice King Seneca Autumn Gold Sundance Summer Scallop Spaghetti Squash Sweet Mama Autumn Queen Early Butternut Hybrid May 16 May 16 May 16 After seeding and transplanting, all rows except those containing beans and corn were covered with a clear perforated row cover using a mechanical hoop setter and tunnel layer. The tunnels were supported with nine-gauge wire hoops spaced on 62 in centers, 14 in high. The bean and corn seedlings were released from underneath the IRT mulch on 5/28/91 by slitting the plastic down the center of the row. The released seedlings were then covered with a clear perforated row cover. The drip irrigation lines were connected to a 1,000 gal storage tank, painted dark brown to absorb heat and thus temper the irrigation water. A fertilizer injector was installed on main distribution lines to provide additional fertilizer during the growing season. Starting on 7/8/91, water soluble fertilizer was added on a weekly basis until 8/14/91. Total fertilizer added was Ib/a of N, P2O5, and K2O, respectively. Two sets of water filters were installed to filter out solids. Water was applied at 8 psi using electric water pumps. Tensiometers (used to measure soil moisture) were installed at four locations in the field to indicate when irrigation was needed. Thermographs with temperature probes 3 in deep in the soil were installed at two locations under the plastic mulch and at one bare soil plot on 5/16/91. Hourly temperatures were recorded until 8/26/91. 12

4 RESULTS: Harvesting began 7/1/91 and was conducted twice weekly throughout the growing season. Production data is given in Table 2. Table 3 shows irrigation water temperature data and Figure 1 graphs average weekly mean temperatures. Table 2, Yield of Vegetable Crops Using Infrared Transmitting Plastic Mulch and Perforated Row Covers - Pyrah's Pioneer Peak Farm, Palmer, Alaska, CROP (VARIETY) 7/1 Zucchini Squash 4 (Seneca) Yellow Summer Squash 12 (Sundance) Cucumbers (Slice King) Scallopini Squash (Summer Scallop) Novelty Squash (Spaghetti) Green Beans (Provider) Buttercup Squash (Sweet Mama) Acorn Squash (Autumn Queen) Early Butternut Squash (Early Butternut Hybrid)1 Pumpkin (Autumn Gold) (Polar Vee)2 (Precocious)1 HARVEST DATE TOTAL 7/8 7/15 7/22 7/30 8/5 8/14 8/19 8/26 YIELD Ib/ft0f row Did not mature. Number of ears/ feet of row. 13

5 Table 3. The Effect of Painted Storage Tank, Exposed Distribution Lines and Trickle Irrigation Lines Under IRT Plastic Mulch on Temperature of Irrigation Water, DATE 7/23 7/24 8/2 8/12 8/26 Mean WEATHER CONDITIONS 65 F, Sunny 63 F, Sunny/Windy 68 F, Cloudy/Windy 50 F, Cloudy/Showers 68 F, Sunny/Windy -. WELL TANK END of 150 ft of HOSE Water Temperature F END of 400 ft of TRICKLE TAPE F Increase 16 TOTAL F INCREASE = 29 0, -C eq , ] 44_ 40~ Figure 1. Average Weekly Mean Temperatures May H 1 h 11 1e 25 June Tunnels removed June 28 \ 1 \ July ^ IRT Palmer a Bare Soil August 14

6 Plastic mulch demonstration at Pyrah's Pioneer Park Farm, Palmer DISCUSSION: Production Data: The top producing squash was spaghetti novelty squash, which produced 1152 lb/ ft of row. The second highest squash yield came from Seneca zucchini squash at 602 lb/ ft of row. Autumn Gold pumpkin yield was 412 lb/ ft of row. The butternut squash and Precocious sweet corn did not mature and produced no harvestable crop. The Seneca zucchini and Sundance summer squash were the first vegetables to mature, with the first harvest occurring 31 days after transplanting. Cucumbers and scallopini squash harvest started 46 days after transplanting. The pumpkins were left on the vines until 9/18/91, There was a light frost on 8/24/91, but the effect on pumpkins and vines was negligible. The pumpkins averaged 12 Ib each and there were 3.75 pumpkins/plant. All vegetables were harvested when they met USDA grades and standards, except the corn and pumpkins, which were left in the field until 9/18/91, when a one-time harvest occurred. Soil Temperature: For the 1991 growing season the IRT mulch with row covers averaged 5.3 F warmer than the bare soil having no mulch or row 15

7 cover (Figure 1), After the row covers were removed on 7/26/91, the mulch covered row soil temperature averaged 6.8 F warmer than the bare soil treatment. The soil warming effect of plastic mulch and row covers increases the production of warm season crops such as corn, beans, and cucumbers. Water Temperature: Table 3 shows the effect of solar heating on irrigation water when stored in a dark tank and distributed in lines exposed to the sun and covered with plastic mulch. Water temperature increased from F to 67 F when stored in a dark painted tank and distributed through irrigation lines exposed to the sun. Research indicates that tempering irrigation water can have positive benefits (Hanan, Winfred, and Goldsberry 1978). The 29 F increase in water temperature may reduce transplant shock and plant wilting and help warm soil temperatures under the plastic mulch. Willy Welch and Andrea Robb with vegetables produced using plastic mulch and row covers, Palmer REFERENCES: Hanan, J. J., Holley D, Winfred, and Kenneth L. Goldsberry Greenhouse Management, New York: Springer-Verlog. pp