Effects of urea and urea treated with nitrogen stabilizers on the growth, yield, and quality of field crops cultivated on Podzols in the boreal climate

Nzwinda, Therese Audrey Mbite (2022) Effects of urea and urea treated with nitrogen stabilizers on the growth, yield, and quality of field crops cultivated on Podzols in the boreal climate. Masters thesis, Memorial University of Newfoundland.

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Abstract

Nitrogen (N) is one of the prime macro nutrients needed to produce crops. Nutritionally poor soils like Podzols, can be amended with N fertilizers to boost crop productivity. However, intensive use of N fertilizers can cause environmental pollution, because about 50% of N applied as fertilizers gets lost through various pathways. Urea (UR) treated with N stabilizers like urease inhibitors (UI) and nitrification inhibitors (NI) can be used to mitigate N losses. I hypothesized that, UR treated with N stabilizers will increase the growth, yield, and quality of field crops cultivated on podzols in boreal climate compared to the untreated UR application. A two-year field experiment was carried out to determine the effect of UI [N-(n-butyl) thiophosphoric triamide - NBPT] and NIs [nitrapyrin and dicyandiamide] on (1) the growth, yield and quality of silage corn, (2) the growth, yield and quality of faba bean and oats + peas mixture, (3) the growth, yield and quality of cash crops such as canola and wheat. Results revealed that forage quality indices: crude fat, calcium, and magnesium in faba beans were significantly decreased by agrotain and superU (containing agrotain and dicyandiamide) compared to untreated UR. Overall, my thesis findings demonstrate the potential of UR treated with N stabilizers to boost crop production on podzols. This information could be useful to improve sustainable agriculture in boreal climates.

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