Submitted to: University of Missouri Agricultural Chemicals Short Course
Publication Type: Proceedings
Publication Acceptance Date: 12/3/1997
Publication Date: N/A
Technical Abstract: The purpose of this research was to test the hypothesis that corn response to N fertilizer rate varies within fields because of the variability in landscape and soil morphological characteristics of soil productivity. Nitrogen response variation within fields was tested during the 1993-95 growing seasons for Missouri claypan and alluvial soil fields, two contrasting soil/landscape settings. The claypan soil studies were locate in north-central Missouri, near Centralia, and the alluvial soil study was located near Oran in the south-east region of the state. Corn grain yields responded differently to N rate within five of the six site-years. Each year was unique because of climate factors. Yield for economic plateau was always within 1 or 2 bu/acre of the physiological plateau. However, the difference between physiological N rate to plateau and economic N rate to plateau varied between 3 and 44 lbs N/acre. These results support developing variable-rate N strategies, but climate information, improved soil and landscape characterization, and within season N application may be needed in order to be successful.