Students who have completed the Soil Nutrient Relationships course at the University of Nebraska-Lincoln often contact instructors once they have begun full-time work, seeking reminders of specific concepts. These students either did not take or keep detailed notes during the course. To assist students, instructors have developed a portfolio requirement for the course. One important learning objective from each recitation exercise was summarized as deliverable knowledge in the student's portfolio. Feedback was then provided on portfolio components each week with resubmission encouraged, so that students leave with accurate information in their own words. The objective of this article is to summarize the details of the portfolio assignment used in Soil Nutrient Relationships to assist other instructors in developing student assignments and assessments. Following completion of the knowledge portfolio, students were surveyed with more than 75% response rate in both the 2016 and 2017 semesters. More than 44% of respondents agreed that they thought they would use the portfolio in their future work, and more than 15% of respondents agreed that the portfolio would be the most important component of class toward their future work.