Biological Systems Engineering, Department of


First Advisor

Amy M. Schmidt

Date of this Version

Summer 7-30-2020

Document Type



Olivo, Agustin. On-farm Research and Student Engagement to Assess and Promote the Use of Organic Amendments to Improve Agricultural Soil Health and Resilience of Crop Production Systems in Nebraska. 2020. Biological Systems Engineering – Dissertations, Theses, and Student Research.


A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Mechanized Systems Management, Under the Supervision of Professor Amy M. Schmidt. Lincoln, Nebraska: May, 2020

Copyright 2020 Agustin Olivo


In nearly every production environment, there are opportunities to capture profits if waste streams can be further processed or enhanced to create “value added” products. On-farm research studies were initiated in 2019 at four locations across Nebraska to assess the impacts of livestock manure, cedar mulch from forestry management and coal char from sugar beet processing, on agricultural cropland. Study treatments included beef cattle manure (CM), beef cattle slurry (CS), coal char (CC), woody biomass (WB) CM+WB, CS+WB, CM+CC and control (CON; no organic amendment). Soil properties and corn yield were evaluated after a single growing season. Results indicate that single pre-plant manure applications can make significant contributions of nitrogen (N), phosphorous (P), and potassium (K), constituting a reliable resource to replace inorganic fertilizers. Depending on initial soil quality, manure also increased soil organic matter (SOM) concentration, pH, and electrical conductivity (EC). Surface applications of woody biomass did not show evidence of soil acidification or N immobilization, although it induced soil nitrate reduction in top soil layers when incorporated after crop harvest. Soil physical properties were mostly unchanged under all treatments except coal char. This treatment significantly increased SOM concentration and pH, and decreased bulk density. However, it also decreased crop yield. In parallel, a program including a combination of classrooms lectures, visual demonstrations and field hands-on activities about soil health, agricultural research and science literacy was created and delivered to students at three Nebraska high schools. Each school was paired with one on-farm research study site. Results of surveys delivered to teachers and students at the end of the program showed that visual demonstrations and field assessments of soil health parameters successfully increased students’ scientific understanding and awareness about the importance of soil health. Notwithstanding, a more detailed program, based on the classes’ plans and specific FFA initiatives may be needed in order to increase the engagement of all actors and take better advantage of students and teachers’ high interest on hands-on activities.

Advisor: Amy M. Schmidt