Issue link: http://read.dmtmag.com/i/138107
SSCD for delivery of foliar inputs To mobile pump, tank, and compressor To irrigation main, and hybrid SSCD manifold Upper line Connecting loop Lower line Hybrid SSCD for delivery of soil inputs Some practical problems needed to be solved. While it seems simple enough to spray pesticide solutions through irrigation lines and sprinklers, what happens next? How would the lines be cleared out? If clear water were used to flush the lines, would it wash off the newly applied spray material? A novel method was developed, which consists of two major components: 1) the canopy delivery system and 2) the applicator. The canopy delivery system is a network of polyethylene irrigation tubing run through the orchard block in a continuous loop with an input and output line that attaches to the applicator. The applicator consists of three major components: 1) a pumping system, 2) an air compressor and 3) a tank for mixing, providing, and recapturing spray material for the canopy delivery system. The four-stage spray procedure consists of the following steps: 1) Charging: Spray material is premixed in the spray applicator and then pumped through the main line at low pressure (less than 18 psi). 2) Spraying: The return line is closed and pressure increased to greater than 30 psi allowing the check valves to open and material to exit through the microsprayers for the time needed to apply 70-100 gallons per acre (less than 15 seconds). 3) Recovery: The return valve is re-opened, and the air compressor set at less than 18 psi to blow any fluid remaining in the main line back into the spray applicator. 4) Cleaning: The return valve is closed and the air compressor set to higher pressure (greater than 30 psi) to clear any remaining spray material out of the microsprayers. Materials While the microsprayer emitters are well developed, it is not clear what kinds of materials might need to be used in constructing the lines. They researchers tested both rigid PVC pipe used in plumbing and flexible polyethylene hose. The microspinklers were spaced three feet apart on drop downs three feet long. There was a somewhat larger pressure drop on the flexible polyethylene hose. "These data suggest that PVC is a superior material for SSCDS plumbing," the report says, but polyethylene is widely used for irrigation and growers are adept at handling it. Details about the project, and the first report, are tavailable online at www.canopydelivery.msu.edu. • www.goodfruit.com GOOD FRUIT GROWER July 2013 9