Summer and Fall-Planted Cover Crops across Nebraska: Assessing Performance Using Aerial Imagery and Evaluating Short-Term Soil Impacts

Authors

Grace Emperatriz Pacheco Jiron, University of Nebraska-LincolnFollow

First Advisor

Andrea D. Basche

Date of this Version

10-2024

Document Type

Thesis

Citation

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: Agronomy

Under the supervision of Professor Andrea D. Basche

Lincoln, Nebraska, October 2024

Comments

Copyright 2024, Grace Emperatriz Pacheco Jiron. Used by permission

Abstract

Cover crops are widely recognized for improving soil health and promoting sustainability in agricultural systems. Despite the increasing use of monitoring tools like aerial imagery, their application in evaluating summer-planted cover crops in the Great Plains remains limited, hindering effective management strategies. Fall-planted cover crops provide long-term environmental benefits, including enhanced soil quality and erosion control; however, understanding their short-term effects on soil properties is crucial for encouraging adoption. This study assessed summer- and fall-planted cover crops across Nebraska, integrating aerial imagery and soil health analyses.

Over two years, fifteen summer-planted monocultures and five mixtures were evaluated for establishment, biomass production, and correlations with vegetative indices (NDVI and NDRE). Corn (BMR grazing corn), sudangrass (piper), sorghum sudan (super sugar), and buckwheat demonstrated rapid establishment, with sorghum sudan (super sugar) achieving the highest biomass. NDRE showed stronger correlations with biomass and plant height than NDVI, particularly in grasses, demonstrating its utility as a monitoring tool.

For fall-planted cover crops, the effects of six fall-planted cover crop treatments on soil biological, chemical, and physical parameters were analyzed. Significant differences in soil electrical conductivity (EC) were observed, with EC being consistently lower in cover crop treatments, highlighting their role in mitigating nutrient leaching. Regions with finer soil textures and higher precipitation, such as Eastern Nebraska, exhibited more pronounced changes in potential mineralizable nitrogen, mineralizable carbon, and β-glucosidase activity, suggesting greater effectiveness of cover crops under favorable conditions. In contrast, fewer differences were observed in Western Nebraska, emphasizing the influence of regional soil and climate variability.

These findings demonstrate the utility of aerial imagery for monitoring cover crops and emphasize the importance of tailoring management practices to regional conditions. Future research should explore multi-year effects to refine recommendations for farmers and inform agricultural policies promoting sustainable practices across diverse landscapes.

Advisor: Andrea D. Basche