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Fluid Journal : Winter 2013
5 The Fluid Journal Winter 2013 Treatments consisted of: • Untreated control with no foliar urea. • Foliar urea. • Foliar urea with NBPT. • NBPT without urea. Each foliar urea application was calculated to supply 11.2 kg of N per hectare. The treatment with urea plus NBPT was applied using the commercial fertilizer Agrotain (Agrotain Int. LLC) and the foliar NBPT rate was calculated based on reports that Agrotain contains 0.84 percent of NBPT. Treatments were applied at 8 a.m . four weeks after planting. Field Methodology Timing. The experiment was uniformly fertilized following preseason soil tests and state extension recommended rates, except for N, which was applied according to the treatments. Treatments consisted of: • Full recommended N soil rate with no foliar N application. • 75 percent of recommended N soil rate with no foliar application. • 75 percent of N soil rate with two foliar urea applications (at first flower and two weeks later). • 75 percent of recommended N soil rate with two foliar urea plus NBPT applications (at first flower and two weeks later). Each foliar urea application was calculated to supply 11.2 kg of N per hectare. The treatment with urea plus NBPT was applied using Agrotain. The full recommended N rate consisted of 125 kg N/ha-1 , and93.7kgN ha-1 was used for 75 percent of the recommended N rate treatment. Soil- applied N fertilization was sidedressed at planting and at the pinhead-square stage using urea. Plots. The experiment was conducted using a plot size of 4 rows spaced 0.96 m apart by 15 m length. Growth Room Results A significant main treatment effect was observed for membrane leakage (P=0.0031) and MDA (P =0.0270). There was a significant decrease in membrane leakage and MDA for the NBPT treatment. For example, compared with the control, the NBPT treatment had a decrease of 20 percent (P= 0.0051) in membrane leakage and Figure 1. Effect of foliar treatments on membrane leakage (A), MDA (B), and glutathione reductase (C) in cotton grown in growth room conditions. N.S. = not significant (P≤0.05).
Early Spring 2013