Nonpoint source pollution (NPS) has become the leading factor of global water quality problems, attracting great attention from governments and researchers in various countries. Based on this situation, understanding the current research status of NPS can help guide future research. However, most of the current reviews only describe the research status of some specific aspects but fail to quantify the research hotspots and development trends on the whole, which limits the overall understanding of NPS. In this paper, bibliometrics was used to study the current status, hotspots, and frontiers of NPS research during 1991-2015, and the future research development was predicted. Over the past 15 years, there has been a remarkable growth trend in publication output, and the participation of countries/territories has also increased. Journal of Environmental Quality, Journal of Hydrology, and Total Environmental Science were the top three journals. Sharpley AN and Arnold JG from the USA were the most productive authors with the best quality articles. The major author clusters and research regions are located in North America and Europe, followed by East Asia. The United States dominates this research field, with the largest number of independent and collaborative articles. Chinese authors gained more attention through international cooperation. Keyword analysis confirmed that water quality and nutrients were the main concerns of NPS pollution research, which mainly involved a number of research topics, such as pollutant emission reduction research and the evaluation and simulation of pollutants' migration and their transformation under different situations, while pesticides were less of a concern, which suggests that the abuse of pesticides has come under control. Meanwhile, SWAT was the dominating model in the last decade partly because it satisfied the growing needs of watershed-scale management.
Keywords: bibliometric analysis; geographic distribution; keyword analysis; nonpoint source pollution.