Economic Feasibility of Variable‐Rate Nitrogen Application Utilizing Site‐Specific Management Zones

Variable‐rate technology (VRT) has been developed to variably apply crop inputs to manage in‐field variability. Although growers have begun to adopt VRT, its profitability is uncertain in N management. The objective of this study was to assess the economics of uniform vs. variable‐rate N fertilizer application under two N application scenarios (farmer vs. custom applications). On‐farm studies were conducted on two continuous corn ( Zea mays L.) fields in northeastern Colorado under furrow and center‐pivot irrigation during the 2000 and 2001 growing seasons. The N management strategies were uniform, grid‐based, site‐specific management zone–constant yield goal (SSMZ‐CYG) and site‐specific management zone–variable yield goal (SSMZ‐VYG). “Profit and loss” software was used to analyze the economics of each N management strategy and determine which N strategy was most profitable. Results from three site‐years consistently indicated that less total N fertilizer (6–46%) was used with the SSMZ‐VYG N management strategy when compared with uniform N management. Net returns from the SSMZ‐VYG N management strategy were $18.21 to $29.57 ha −1 more than uniform N management. Results of this study suggest variable‐rate N application utilizing site‐specific management zones are more economically feasible than conventional uniform N application.