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United States Department of Agriculture

Agricultural Research Service

Title: Applying GIS for Interpretation of Spatial Variability on Yield

Authors
item Bakhsh, A - IOWA STATE UNIVERSITY
item Colvin, Thomas
item Jaynes, Dan
item Kanwar, R - IOWA STATE UNIVERSITY
item Tim, U - IOWA STATE UNIVERSITY

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 1, 1999
Publication Date: N/A

Technical Abstract: A study was conducted to investigate the relationship between soil attributes and corn (Zea mays L.)-soybean (Glycine max L.) Yield variability using four years (1995-98) yield data from a 25-ha field located in central Iowa. Corn was grown in this field during 1995, 1996 and 1998, and soybean was grown in 1997. The yield data were collected on nine east-west transects, consisting of 25 yield blocks per transect. Yield data were normalized based on N-fertilizer treatments and were used in the subsequent analysis. The soil attributes of bulk density, cone index, organic matter, aggregate uniformity coefficient and plasticity index were determined from the field data collected at the 42 sampling sites of the field. The correlation matrix and stepwise regression analysis under different soil types of the field revealed that the Tilth Index did not show a significant relationship with the yield data for any year and may need modification in its suitability ranges of tilth coefficients for this field. The regression analysis showed a significant relationship of soil attributes to yield data for Harps and Ottosen soils. This was further explored during map overlay analysis of yield, soil type and topography performed with ARC/INFO, GIS software. Both methods showed that Ottosen soil has a significant relationship with yield patterns. The map overlay analysis showed that higher yield polygons may be influenced partly by management practices and partly by topography at lower elevations. GIS and statistical analysis both concluded that interaction of soil type and topography have influence on yield variability patterns for this field.

Last Modified: 11/21/2014
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