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Fluid Journal : Fall 2013
10 The Fluid Journal Fall 2013 Figure 1. Effect of NutriSphere-N on random hand harvest process tomato yields with sub-surface drip and in-season UAN applications. "Results suggest NutriSphere-N increases sub- surface drip UAN efficiency." Nitrate (UAN) 32% N was made on May 23, 2012. It was anticipated that there would be 10 applications of UAN-32 during the growing season at approximately weekly intervals. The NutriSphere-N (L) was injected at a rate of 8 oz in two gallons of water per 2-acre plot on the 1st, 3rd, 5th, 7th, and 9th, with UAN applications starting 30 minutes prior to UAN fertigation applications (for a total of 20 oz/A of NutriSphere-N/acre/ season). Equipment. NutriSphere-N was injected into each 2-acre plot at the modified riser using a 2.5 gal EZ-Flow fertilizer tank (tanks were set on the fastest application setting). Four 2.5 gallon EZ flow tanks and induction couplings were provided by Simplot for use during this study. N rate. A total of 200 lbs/A was applied in 10 fertigation applications during the growing season. Treatments. Three treatments were evaluated for this study: • Grower Standard Practice (G) = no additional treatment • NutriSphere-N application prior to the 1st, 3rd, 5th, 7th, and 9th UAN fertigation applications • 90 percent GSP + NutriSphere-N application prior to the 1st, 3rd, 5th, 7th, and 9th UAN fertigation applications. UAN applications were not to be made to these plots during the 4th fertigation cycles. Plots were 24 rows by the length of the field (725 feet or approximately 2 acres per plot). Injection. NutriSphere-N was injected into the 2-acre plot area using an EZ Flow mainline dispersing tank connected to the induction coupling. Risers were modified with the installation of an injection coupling, which was attached to the mainline dispersing tank with a hose. The injection coupling creates a suction that then empties the tank while the tank is turned on. The tanks were turned on during the first 30-minute pre-fertigation cycle when only water was running through the system. Replication. Each N-N treatment was replicated two times for a total of four plots. The balance of the field received no additional treatment (grower standard practice). Plant tissue analyses were collected twice during the growing season and analyzed for nutrient status. Tomato leaf analyses as sampled on July 5th are presented in Table 1. NutriSphere-N did not have any effect on tomato leaf nutrient analysis; all values were in the sufficiency range. Hand harvest. Plots were sub-sampled on September 25, 2012. Four random 10 linear feet of row plots were hand harvested and separated into red, yellow,
Late Spring 2013