Stacie Yaremko | ALES Graduate Seminar

Date(s) - 24/01/2025
2:00 pm - 3:00 pm
442B Earth Sciences Building, Earth Sciences Building, Edmonton

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 Stacie Yaremko. This seminar is open to the general public to attend.

Zoom Link: https://ualberta-ca.zoom.us/j/97268491511?pwd=trsv2tzYc9wIvALFr9om5PoNgeFNOv.1


MSc with Drs. Miles Dyck and Sylvie Quideau


Thesis Topic: Applications of Multinutrient Fertilizers to Improve Mature Mixed Forage Stands in Northern Alberta


Abstract:

This thesis examines the efficacy of multinutrient fertilizer products in increasing biomass yield, plant nutrient uptake, and residual soil nutrients of mature mixed forage stands. Three sites were established in Northern Alberta; one near Breton and two near Beaumont. The study was conducted for three years, from 2021 to 2023. Eight treatments were applied: an unfertilized control, three nutrient exclusion treatments (removing nitrogen, phosphorus, and sulphur from the blends), and four “complete” treatments containing nitrogen, phosphorus, potassium, and sulphur. Three of the complete treatments included multinutrient fertilizer products, while the fourth was a blend of conventional fertilizers. One of the complete multinutrient fertilizer treatments contained exclusively sulphate-sulphur, one contained equal portions of sulphate-sulphur and elemental sulphur, and one contained exclusively elemental sulphur.

While there were forage biomass yield responses to added fertilizer over the unfertilized check and nutrient exclusion treatments, there were no yield differences found between the complete fertilizer treatments. Further, the sites were largely unresponsive to individual additions of nitrogen, phosphorus, potassium, or sulphur. The experiment year, representing a range of moisture and temperature conditions over the three year duration of the experiment, tended to be more predictive of forage biomass yield than fertilizer treatment.

Plant nutrient uptake and residual soil nutrients responded in a fashion similar to biomass yield, with the year of the experiment having a strong influence on these factors and few statistically significant differences between complete fertilizer treatments.

Elemental sulphur has been extensively studied on the Prairies and it has generally been thought to oxidize too slowly for annual crops in this relatively cool and dry climate. Surface applying elemental sulphur to perennial crops is likely the best fit for elemental sulphur, because of the increased weathering and dispersion compared to subsurface banding applications and the longer timeline of sulphur uptake of perennial crops. Additionally, new formulations of elemental sulphur have smaller particle sizes than those of the past, which should also facilitate more rapid oxidation. Because the sites in this study were not sulphur-responsive, little could be determined about the oxidation rate and subsequent plant uptake of the elemental sulphur products in this project.

While the addition of fertilizer did, in general, increase forage biomass yields, fertilizer marketing claims of enhanced efficiency or greater nutrient uptake of multinutrient fertilizer products than conventional fertilizer blends could not be supported by this study. Repeating the work on sites with a greater proportion of legumes, or using higher nitrogen rates on predominantly grass stands, may be beneficial. Future work examining feed quality in greater detail in response to these fertilizer products may produce interesting results, as well.


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