Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)


Plant Science

First Advisor

Paul Fixen


It has been predicted that the cost of nitrogen fertilizer will soon triple. Consequently, N management by wheat growers in South Dakota will be even more critical than it has been in the past. Nitrogen is one of the most limiting nutrients for wheat production in South Dakota. Many of the spring wheat producers fail to take advantage of nitrogen fertilizer recommendations based on soil testing. Therefore, it is likely that a simple post-harvest method of determining if adequate N was present for wheat crop would be very beneficial to spring wheat producers. One such method is using grain protein content as an indicator of N sufficiency or insufficiency. In 35 experiments that were conducted from 1963 through 1981, grain protein content was utilized to determine N response. This technique of using the grain protein content proved to be a useful indicator of yield response for spring wheat. Nine varieties were classified into three groups representing high, medium, and low grain protein content. These varieties were grown at three locations to determine their response to five levels of N fertilization. In general, all varieties produced similar yield and protein responses to varying N rates even though their general ranking for protein remained constant. The purpose of this study was three fold: (1) to determine the importance of variety selections on wheat yield and protein response to N; (2) to develop a model to predict the N required to maximize both yield and grain protein content and compare it with the existing model for nitrogen fertilizer recommendations; {3) to determine the relationship between relative grain yield and percent grain protein content.

Library of Congress Subject Headings

Plant proteins
Nitrogen fertilizers
Wheat -- Fertilizers and manures
Wheat -- South Dakota



Number of Pages



South Dakota State University