Agronomy and Horticulture Department

 

First Advisor

Andrea D. Basche

Second Advisor

Javed Iqbal

Third Advisor

Cody Creech

Date of this Version

10-2023

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 2023

Comments

Copyright 2023, Roberta Bianchin Rebesquini

Abstract

The intensive management associated with many annual crops often includes recurring tillage, fertilization, and pesticide applications, which contribute to environmental concerns such as water pollution and soil erosion. Intermediate wheatgrass (Thinopyrum intermedium), recognized under the trade name Kernza®, is a perennial grass that can be managed to produce grain and biomass while providing desired environmental benefits such as soil conservation and nutrient cycling. There has been limited research on best management practices and crop productivity for this alternative dual-use crop in Nebraska. A field experiment was conducted beginning in 2021 to assess nitrogen (N), phosphorus (P), and potassium (K) management practices for intermediate wheatgrass (IWG) grain and forage production and how it changes over the years of the stand. Additionally, a meta-analysis of 16 independent studies was conducted to evaluate the impact of nitrogen rates across sites and years on intermediate wheatgrass productivity. The meta-analysis found limited effects on grain yield in year 1 but optimal rates ranging from 51-150 kg N ha-1 in later years. In our field experiment for years 1 and 2, N, P, and K rates did not impact yields, while second year yields were much lower than the first year, likely due to dry spring conditions during anthesis. Our findings highlight the importance of strategizing the fertilization practices across the intermediate wheatgrass stand years in order to maximize grain and forage production. Moreover, IWG demonstrated its potential as a low-input, alternative, and dual-use cash crop for Nebraska producers.

Advisor: Andrea D. Basche

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