Sumedha Nallanthighal | ALES Graduate Seminar

Event details: A graduate exam seminar is a presentation of the student’s final research project for their degree.
This is an ALES MSc Final Exam Seminar by Sumedha Nallanthighal. This seminar is open to the general public to attend.

Zoom Link: https://ualberta-ca.zoom.us/j/98216576748?pwd=y6CzwojRXgzgaRzyeWG00ytbtwn3au.1

MSc with Dr. Linda Gorim.

Thesis Topic: Humalite for enhanced wheat and canola production in the Canadian Prairies

Abstract:

As the global population approaches 10 billion by 2050, sustainable food production faces unprecedented challenges. Nitrogen (N) fertilizers, crucial for crop yields, contribute significantly to agricultural greenhouse gas emissions and environmental degradation. The 4R Nutrient Stewardship framework (Right source, Right rate, Right time, Right place) aims to optimize fertilizer use efficiency while minimizing environmental impact. In addition, alternatives such as plant biostimulants are advocated to increase plant N uptake and protect them against abiotic stress thereby, important for sustainable crop production. One such biostimulant is Humalite, a naturally occurring form of an oxidized coal-like substance containing high levels of humic acid and low amounts of heavy metals. The Prairie Mines and Royalty ULC, Hanna, Alberta holdings (currently WestMet Ag) have large Humalite deposits that are unique due to a higher percentage of humic acid resulting from freshwater deposition. Humalite is known for its ability to improve plant agronomic parameters and increase crop N use. Limited field research exists on the effect of Humalite, application rate, and interaction with urea, especially at reduced rates on grain agronomic parameters. Therefore, a field study was conducted from 2021 to 2023 at three Alberta sites – Battle River Research Group (BRRG), Gateway Research Organization (GRO), and St. Albert Research Station (St Albert), in a split-plot design with four replications, three urea levels (i.e. recommended, half recommend, and zero urea) combined with five Humalite rates (0, 56 (or 112), 224, 448, and 896 kg ha^-1). In 2021, the highest wheat yields were observed at half urea rates plus 224 kg ha^-1 at BRRG (35% yield increase), at GRO (8.4% yield increase); and at St Albert (33.5% yield increase). In 2022, canola yields were unaffected by Humalite application rates. In 2023, wheat yields from half-recommended and recommended urea rates plots outperformed zero urea plots across all sites, regardless of Humalite rates. The highest wheat grain protein content values were observed at 224 – 448 kg ha^-1 of Humalite plus half or recommended urea rate. Depending on the site, the highest net revenue resulted from half urea rates plus Humalite at application rates between 112 – 448 Kg ha^-1 in wheat i.e. optimal Humalite rate for increased profitability.

Enhanced efficiency N fertilizers (EENFs) are innovative fertilizer products designed to improve N availability to crops while reducing environmental losses. Among these, double inhibitor fertilizers, also known as dual inhibitors, are particularly effective in optimizing N use efficiency by utilizing nitrogen inhibitors to improve soil N retention and make it more available to the plant. Building on the field study results, a controlled environment experiment was conducted at the University of Alberta from November 2023 to May 2024 to further investigate the optimal Humalite application rate of 448 kg ha^-1. This greenhouse study focused on the interaction between Humalite and EENFs on wheat and canola growth. The experiment compared SuperU®, an EENF, with conventional urea at recommended and reduced (70%) rates, combined with Humalite. A total of seven treatments, including a control, were evaluated over two growth cycles. Results revealed that Humalite was more effective in enhancing wheat growth compared to canola. Under optimal conditions, wheat grown with reduced urea rate plus Humalite demonstrated the highest N fertilizer recovery rate and comparable agronomic N efficiency to the recommended urea rate, however, with significantly lower yields. Interestingly, Humalite application did not show additional benefits when combined with SuperU® under ideal conditions. However, during a heat-stressed cycle, Humalite increased wheat yields when combined with reduced SuperU® compared to recommended SuperU®. This effect was not observed in canola. For wheat, reduced SuperU® was as effective as the recommended rate, producing similar yields as that of recommended urea and higher protein content than recommended SuperU®. In contrast, canola responded similarly to the recommended rate of both SuperU® and urea. These findings suggest that incorporating Humalite and using reduced rates of dual inhibitor EENFs could potentially decrease urea usage, contributing to more sustainable and economically viable wheat production systems.