Approaches to Variable Rate Nitrogen Management in the Eastern Cornbelt. (S04-brock835649-poster)
Authors:
A.N. Brock* - Purdue University S.M. Brouder - Purdue University G. Blumhoff - Purdue University
Abstract:
Yield and soil productivity potential are common components of nitrogen (N) recommendations for corn (Zea mays L.). Our objective was to compare the efficacy of N management zones based on 1) multiple years of yield monitor data, 2) surface soil organic matter (SOM), and 3) soil survey data. N rate studies were conducted in 2001 and 2002 on four fields each of which had yield monitor data from six previous years (3 yrs each of corn and soybean (Glycine max L. Merr.)). Continuous SOM maps were developed from intensive soil sampling regimes. The fuzzy c-means unsupervised clustering algorithm was used to classify each field into zones using yield data or SOM. Reduction of within-zone yield and SOM variance resulting from zone delineation identified 3 to 4 distinct yield-based and 2 to 3 distinct SOM-based zones respectively. ANOVA was used to evaluate stability of yield and SOM between zones as well as corn yield response to applied N. Preliminary analyses found optimum whole field N rates to range from 168 (field F) to 202 (field R) kg ha-1. Using 3 zones, field F yield-based zones had optimum N rates of 101 to 202 kg ha-1 while SOM-based zones were between 134 and 168 kg N ha-1. Field R yield-based zone rates were comparable to the whole field N rate while
SOM-based zones found one zone to be nonresponsive to N. These zones must still be compared with soil surveys.
Speaker Information: Adam Brock, Purdue University, Department of Agronomy 915 W. State Street, West Lafayette, IN 47907; Phone: 765-494-8080; E-mail: [email protected]
Session Information: Tuesday, November 4, 2003, 2:00 PM-4:00 PM Presentation Start: 2:00 PM (Poster Board Number: 1028)
Keywords: Soil property and historical yield maps; Fuzzy classification; Management Zones; Soil-specific N response curves
