One of the chief problems with which soils investigators have been concerned for a number of years is that of securing a laboratory test that will serve as an index to the fertility of the soil. In as much as nitrogen is so important an element in crop production it is believed that the power of the micro-organisms to oxidize the nitrogen of the soil would be an indication of the crop producing power of that soil. A very good review of the literature on this subject has been given by Waksman. (1) (2) After a detailed investigation of this problem he came to the conclusion that the ammonification test could not be used as a criterion in determining the fertility of the soil. On the other hand he found a very close correlation between the crop producing power of the soil and its nitrifying power.
Proceedings of the Iowa Academy of Science
©1925 Iowa Academy of Science, Inc.
Walker, Rudger H.
"Bacterial Activities in an Orchard Soil,"
Proceedings of the Iowa Academy of Science, 32(1), 77-80.
Available at: https://scholarworks.uni.edu/pias/vol32/iss1/11