An Economic Analysis of Alternative Nitrogen Fertilization Methods for Sugarbeets

Sugarbeet ( Beta vulgaris L.) producers face unique challenges in N fertilizer management because of the relationships among price, sucrose content, and root yield. This study evaluates the economic efficiency of N fertilizer applications using broadcast, knife band, and point injection application methods. The most profitable rate of N was examined for each application method under goals of profit maximization, root yield maximization, sucrose‐yield maximization, and recoverable sucrose‐yield maximization. This study was based on production data collected at the University of Wyoming Research and Extension Center at Powell from 1991 to 1993. The experiment was conducted as a randomized complete‐block design with four replications of each treatment. Treatments consisted of a control (no applied N) and factorial combinations of four N rates (80, 160, 240, and 320 lb N/acre in 1991 and 60, 120, 180, and 240 lb N/acre in 1992 and 1993) with each application method. Response functions relating the amount of N applied to gross returns, root yield, sucrose yield, and recoverable sucrose yield for each of the three application methods were used to derive the optimal amount of N to be applied. Point injection returned $966/acre above fertilizer and beet hauling costs while broadcasting and knife banding returned $899/acre and $872/acre, respectively. Profit maximizing N rates were 187 lb/acre for point injection, 187 lb/acre for knife banding, and 220 lb/acre 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 returned income above fertilizer and beet hauling costs and used fertilizer levels that fell between those of maximizing profit and root yield. Research Question Sugarbeet producers face unique challenges in N fertilizer management because of the relationship among price, sucrose content, and root yield. Excessive N rates not only increase, fertilizer costs, but also reduce economic returns. This study evaluates the economic efficiency of N fertilizer applications for sugar‐beets using broadcasting, knife banding, and point injection application methods. The most profitable rate of N was examined for each application method under the producer goals of profit maximization, root yield maximization, sucrose yield maximization, and recoverable sucrose yield maximization. Literature Summary Studies have shown that broadcasting exhibits lower fertilizer‐use efficiency due to surface runoff N losses, leaching, denitrification, immobilization, and volatilization. Knife banding overcomes some shortcomings of broadcasting, such as surface runoff and volatilization, by injecting N under the soil. Negative effects of knife injection include large amounts of soil disturbance, crop residue, and increased pruning of plant roots. Point injection has been shown to require less horsepower than knife banding and create negligible soil and crop disturbance while allowing for more precise fertilizer placement. Studies on the economic efficiency of the three fertilizer application methods are nonexistent. Study Description This study was based on production data collected at the University of Wyoming Research and Extension Center at Powell from 1991 to 1993. Each application method (broadcasting, knife banding, and point injection) was replicated four times at each N rate. There were four N rates (80, 160, 240, and 320 lb N/acre) in 1991, and four N rates (60, 120, 180, and 240 lb N/acre) the following 2 yr. There were also four control plots (0 lb N/acre) in each year. Response functions relating the amount of N applied to gross returns, root yield, sucrose yield, and recoverable sucrose yield for each of the three application methods were used to derive the optimal amount of N to be applied. Models were tested to examine the influence of yearly variations of weather and planting and harvesting dates. To determine the profit maximizing application method and associated N rate, a profit function was specified for each fertilizer application method. To examine the economic efficiency associated with each fertilizer application method, a partial budgeting framework—where only those costs changing between fertilization methods—was used to determine costs associated with each method. Applied Questions What is the most economically efficient method of N fertilizer application in sugarbeets: broadcasting, knife banding, or point injection? Point injection returned $966/acre above fertilizer and beet hauling costs while broadcasting and knife banding returned $899/acre and $872/acre, respectively. Per acre ownership and operation costs were $3.01 for point injection, $2.71 for knife banding, and $3 for broadcasting. Optimal N rates were 187 lb/acre for point injection, 187 lb/acre for knife banding, and 220 lb/acre for broadcasting. Root yield and sucrose yield were higher for point injection and lowest for knife banding. Which producer goal (maximize profit, root yield, sucrose content, or recoverable sucrose) returns the most profit and requires the lease N application? As economic theory would imply, the goal of maximizing profits returned the greatest income above fertilizer costs and necessitated the least N. Maximizing root yield returned the least income above fertilizer costs and required the most N. Maximizing sucrose yield and maximizing recoverable sucrose required higher N rates and returned profits between those obtained from profit maximization and root yield maximization.