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Fluid Journal : Fluid Journal 1996-1998
Winter 1998 Summary: Point injection returned $966/A above fertilizer and beet hauling costs while broadcasting and knife banding returned $899 and $872, respectively. Profit maximizing N rates were 187 lbs/A for point injection, 187 lbs/A for knife banding, and 220 lbs/A for broadcasting. The goal of maximizing profits returned the greatest income above fertilizer and beet hauling costs. Maximizing root yield returned the least income above fertilizer and beet hauling costs and required the most N. Maximizing sucrose or recoverable sucrose yield used fertilizer levels that fell between those of maximizing profit and root yield, plus returned income above fertilizer and beet hauling costs. ________________________________ Sugarbeet producers face unique challenges in N fertilizer management because of the relationships among root yield, crop quality, and price. Top sugarbeet yields require high N rates, but excessive N supply decreases root sucrose content. Sugarbeet payments are based on tons of sugar delivered, and sucrose yield is determined by both root yield and sucrose content. Sucrose yield increases as N rates increase, reaches a maximum sometime before root yield reaches a maximum, then falls because of declining sucrose content and the plateau of root yield. Excessive N rates, therefore, not only increase fertilizer costs but also reduce economic return. Nitrogen management is thus more challenging for sugarbeets than for many other crops in which modest N excesses have little effect on crop quality. A second important challenge in N management is the environmental hazard that results from improper N use. High N rates and intensive irrigation used in sugarbeet production in the western US can produce large N leaching. Shallow soils and high water tables, common in many irrigated valleys, make N leaching an environmental concern as well as an economic loss. Such threat to profit margins plus increasing environmental concerns merely amplify the importance of better N management. Precision N placement can help sugarbeet producers do a better job managing economic and environmental resources. Objectives of this three-year study were to evaluate the economic efficiency of N application options, using broadcasting, knife banding, and point injection. A secondary objective was to examine the most profitable rate of N application for sugarbeets, depending upon the producer's goal and method of application. Maximizing return Optimal N rate, root yield, and costs from our field studies are shown in Table 1. Sucrose yield, gross revenue, and net Drs. L. W. Van Tassell, Alan D. Blaylock, Bozheng Yang Point Injection of N Shines in Sugarbeet Trials Wyoming researchers provide economic analysis comparing broadcasting with point injection and knife banding. Table 1. Optimal N rate, root yield, and costs for three N placement methods on sugar beets, Van Tassell et al., University of Wyoming, 1991-93. Broadcast Point injection Knife banding Optimal N rate--lbs/A 220 187 187 Root yield--tons/A 27.0 28.5 25.8 Fertilizer/application costs--$/A 65 56 55 Beet hauling costs--$/A 64 67 61
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