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Fluid Journal : Fluid Journal 1993-1995
spring. All but one showed greater protein content from late foliar application. There was a significant nitrogen by urea interac- tion for grain protein (giving a smaller response to urea at high N) in only one experiment. There were indications in other experiments, however, that a lesser response to foliar urea at high N might occur, espe- cially at Harper Adams in 1990. This type of interaction also has been found by other researchers from earlier foliar urea applica- tions during tiller development of spring wheat. A late foliar spray of urea (36 lbs N/A) gave a greater increase in grain protein content than the same amount of additional N soil-applied in the spring at all levels of N tested and at all sites except Harper Adams in 1990. Thus, for protein content it was better to apply a late spray irrespective of how much N had been applied in the spring, rather than applying additional N in the spring. Dr. Kettlewell is senior lecturer and Cooper is graduate research assistant at the Crop and Environment Research Center, Harper Adams Agricultural College, UK. ! 135 130 125 120 115 110 105 100 Yield (bu/A) Grain Protein % Soil-Applied N --- lbs/A 12 11 10 9 Figure 2. Effects of soil-applied UAN in spring and late applied foliar urea on yield and grain quality of winter wheat at Eyeworth, Kettlewell, et al., UK. Soil Applied N + Foliar Urea (21.4 gal/A) Grain Protein 0 44 132 222 Table 1. Site details and experimental design, N management study, Kettlewell, et al., Harper Adams Agricultural College, UK. Site Soil Soil Soil Previous Varieties Sowing Design texture organic mineral crop date matter N to 35 inches % lbs/A Harper Sandy 2.0 108 Potatoes Mercia & 10/18/90 Three Adams loam Avalon randomized blocks, split-pot with variety main plots Eyeworth Clay 2.6 108 Spring Mercia 10/9/90 Three loam beans randomized blocks Fall 1994
Fluid Journal 1996-1998