Lawns in the Salt Lake Valley up to 100 years old are not yet saturated in the nutrient nitrogen, which is added by fertilizer, according to a new study. The result is surprising, since previous studies in the Eastern US suggested that fertilized soil would become saturated with nitrogen within a few decades. Rose Smith, post doctoral research associate of biology, served as the study's lead author. Philip Dennison, professor of geography, and others served as co-authors. Read more.