Wednesday, November 15, 2006

Nitrogen Fertilizer Applications for Corn Based on Sufficiency Index Calculations.

Gary Varvel, Wallace Wilhelm, John Shanahan, and James Schepers. USDA-ARS, Lincoln, NE 68583-0934

Corn was grown in both continuous corn and corn/soybean cropping systems under irrigation in the Platte Valley of Nebraska.  The objective of the study was to determine whether in-season N stress measured by using chlorophyll meters could be used to determine N fertilizer applications. Four corn hybrids differing in yield potential, maturity, and stay green characteristics were tested in both the monoculture and rotation systems in combination with five N fertilizer rates. Normalized chlorophyll meter readings, denoted as a sufficiency index, at various growth stages appeared to be indicative of various levels of N stress for the various preseason N fertilizer applications.

Handout (.pdf format, 124.0 kb)