ABSTRACT
To our knowledge, geographical information system (GIS)-based site-specic nitrogen management (SSNM) techniques have not been used to assess agricultural energy costs and efciency. This chapter uses SSNM case studies for corn (Zea mays L.) grown in Missouri and cotton (Gossypium hirsutum L.) grown in Texas. In ve case studies, the impact of SSNM will be compared with blanket N fertilizer recommendations. The ve case studies are investigating (1) the impact N on energy produced in cotton production, (2) the impact of variable-rate N for cotton production based on soil nitrate and crop re°ectance, (3) the feasibility of variable-rate N based on corn crop re°ectance, (4) the use of corn management zones and crop re°ectance for improving N recommendations and energy efciency, and (5) the ability of using aerial photographs to improve N recommendations in corn.
