New publication on spatial characterization of soybean yield and quality

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A new publication, titled “Spatial Characterization of Soybean Yield and Quality” is now available through K-State Research and Extension. The authors include K-State cropping system specialist Ignacio Ciampitti and post-doctoral researcher Yared Assefa, along with agronomists from Iowa State University, Purdue University, Illinois Soybean Association, South Dakota State University, and the University of Minnesota.


Harvested U.S. soybean acres increased from 72 to 89 million acres from 2000 to 2017. A primary driving factor for the growing trend in soybean production is its economic importance due to versatile end uses, serving as an oil seed crop, feed for animals, protein source, and biofuel feedstock.

Study Objective and Methods

Seed amino acid composition is one of the main factors determining overall soybean quality, leading to this study of the variation in seed amino acid concentration across the country. This study assessed the spatial association in amino acids concentration for the major U.S. soybean producing regions; and investigated relationships between seed quality indicators.

Data was collected from soybean testing programs in 14 states (Figure 1) from 2012 to 2016. Annual measurements of yield, oil, protein, and amino acid concentrations were all determined for each site. As a part of the overall evaluation, amino acids measured included arginine, cysteine, isoleucine, leucine, lysine, methionine, threonine, tryptophan, and valine.

Figure 1. Soybean testing trial locations. Circles represent locations and colors represent regions with similar maturity groups. Graphic from MF3455 “Spatial Characterization of Soybean Yield and Quality”, K-State Research and Extension.


This study confirmed the correlation between the concentration of protein and oil with latitude. It also found some correlation between essential amino acids and latitude. This geographical analysis reflects overall amino acid concentrations for soybean sourced from northern regions are lower than southern areas.

The entire publication with more information detailing the data collected, charts and figures, and results can be found online at:

The United Soybean Board (USB Project #1820-152-0108) and K-State Research and Extension provided funding to support this work. The authors appreciate the contribution of FIRST Seed Tests in providing the database presented in this synthesis-analysis.



Ignacio Ciampitti, Kansas State University

Sotirios V. Archontoulis, Iowa State University

Shaun N. Casteel, Purdue University

Daniel Davidson, Illinois Soybean Association

Péter Kovács, South Dakota State University

Seth Naeve, University of Minnesota

Tags:  soybean yield publication