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Fluid Journal : Winter 2012
8 The Fluid Journal Winter 2012 Dr. Guertal is a Professor of Turfgrass Soil Fertility at Auburn University. Table 1. Sod strength of harvested hybrid bermudagrass sod as measured by tensile pull, 2009-2010, Auburn, AL. Sod Strength Data Auburn Fluid Sod test Numbers are the foot pounds at which the sod tore Data is the average of five randomly selected pieces of sod, per plot, average of 4 replications 2009 Study Oct 19 2009 April 19 2010 Control 25.3 b 41.9 c UAN 49.6 a 73.0 b 29-2-3 65.4 a 87.5 a AS (21-0-0) 47.1 a 74.4 b 2010 Study 14-Jul-10 17-Aug-10 18-Nov-10 Control 0b 17.6 b 29.6 b UAN 21.7 a 37.5 a 49.5 a 29-2-3 22.9 a 37.8 a 51.9 a AS (21-0-0) 23.2 a 36.6 a 51.7 a Within each sample date and year means followed by the same letter are not significantly different from each other at alpha = 0.05. sod was allowed to regrow for the next harvest. Data collection. Each week the following data were collected from each plot by: 1. Phytoxicity using a 1-9 relative scale (1= none, 9 = complete damage) 24 hours after spraying, with repeated ratings until damage was gone 2. Percent establishment as determined via a line-transect method (a string with 50 marks was stretched across each plot in 2 places, and the number of times plant tissue hits a mark was counted towards a measurement of percent establishment) Additional data collection included determinations of shoot density and fall soil analysis (0 to 3-inch sampling depth) for 2M KCl extractable soil nitrate and ammonium. One half of each plot area was used for destructive data collection as the plots matured. Three sections of sod (18 x 24 inches) were randomly collected from the destructive half of each plot, cut using the sod cutter. These sections were used to determine sod strength, using a sod strength machine, which determined the tensile strength (measured as a resistance against a measured pull) of the harvested sod. Results In both years of the study there was never any evidence of phytotoxicity (turf burn) due to the application of any N sources. Additionally, the interaction of N rate and N source was rarely significant for any of the measured variables. Thus, results discussed in our conclusions to follow will focus on the separate main effects of N source and N rate. N source. In 2009 sod that had received 29-2-3 (fluid triazone) as the N source had greater sod strength than that fertilized with UAN or ammonium sulfate. Any fertilized sod was stronger than that which was not fertilized. In 2010 there was no difference in sod strength due to N source and all fertilized sod was stronger than unfertilized (Table 1). Shoot density (2009 data only) was also unaffected by N source. N rate. In both years establishment was maximized at an N rate of between 5.6 and 6.0 lbs/1,000 square feet/year, indicating that the highest N rate of 6 lbs was often needed to effectively and quickly grow a sod crop. In both 2009 and 2010 sod strength was maximized at an N rate of 4.6 lbs/1,000 square feet/ season. Conclusion. To date, use of N sources such as UAN did not negatively affect sod establishment or strength. These sources offer an alternative N source for sod growers and may be especially useful in fertigation. Essential crop functions are dependent on complex interactions between NPK and micronutrients. The correct amount of some nutrients - and not enough of others -- can starve crops and reduce yield potential. Remember the Law of the Minimum: "Yields are limited by the nutrient in shortest supply." If your goal is to improve fertilizer e ciency -- by growing more with less to reduce costs and protect the environment -- don't overlook the power of micronutrients. Micronutrients a necessity for higher yields Micronutrient Manufacturers Association (MMA) PO Box 8563 · Woodland, CA 95776 · 916.539.4107 · www.micronutrientfertilizer.com The mission of the MMA is to promote and educate agri-dealers and growers on the importance of using micronutrients to acheive maximum economic yields.
Early Spring 2012