During the past 20 years an investigation has been underway to determine the nitrogen, phosphorus and organic carbon content of the various soils of Iowa. Samples were taken of the various soil types mapped in each county and they were then analyzed. A statistical analysis of the results has been made to determine the average nitrogen, phosphorus and organic carbon content of each soil type, and also to determine the significance of the differences between types.
Proceedings of the Iowa Academy of Science
©1935 Iowa Academy of Science, Inc.
Brown, P. E. and Walker, R. H.
"The Nitrogen, Phosphorus and Organic Carbon Content of Iowa Soils,"
Proceedings of the Iowa Academy of Science, 42(1), 105-106.
Available at: https://scholarworks.uni.edu/pias/vol42/iss1/36