Individual, country, and journal self-citation in soil science

Self-citation is common practice in most sciences but it differs between disciplines, countries and journals. Here we report on self-citation in soil science. We investigated citations in the major soil science journals and conducted an analysis on a country basis and for the subdiscipline of Pedometrics. It was found that the median rate of individual self-citation was 12%, and ranged from 5 to 60% in 31 soil science journals. A high rate Of journal self-citation was accompanied by a high impact factor ranking, but ranking based on the Eigenfactor (TM) revealed a very different ranking compared to the impact factor score ranking. The distribution of country self-citation rate follows a power law, and a logarithmic function was fitted to the data. Taking into account the logarithmic function, China had high Fates of self-citations whereas Egypt, Algeria, Ukraine, and Indonesia have low levels of self-citations. With few exceptions, self-citation rates in soil science are reasonable and comparable to the other biophysical sciences. (C) 2009 Elsevier B.V. All rights reserved.