Agriculture is a very important part of the overall state economy – and crop production is a large part of the agricultural economy. The Kansas State University Department of Agronomy observed their Centennial Celebration in the fall of 2006 and as part of the celebration, several department historical presentations were prepared. Over the past century, much progress has been made in understanding limiting factors affecting Kansas crop production. While climate is often thought to be the predominant factor limiting crop yields, oftentimes it is crop nutrition that limits crop production and profitability. This poster presents a 100 year timeline of significant fertilizer and soil fertility/soil testing related contributions to Kansas crop production as well as an accompanying timeline detailing the history of fertilizer nutrient use in the state of Kansas.