One must consider the effects of both soil N and fertilizer N, if rates of N-fertilizer application are to be optimized and NO$ sb3 sp-$ leaching into groundwater be controlled. Objectives were (1) to determine soil $ rm NO sb3 sp-$-N and NH$ sb4 sp+$-N, soil total N, and N fertilizer levels and corn and wheat yields; and, (2) to determine soil sampling times and depths for N analyses that correlated with yields and fertilizer N response. Soil samples taken at seeding and postseeding were analyzed for NH$ sb4 sp+$-N and NO$ sb3 sp-$-N, and for total N in 29 wheat sites and 44 corn sites fertilized with four rates of N. N-Trak (quick test) and laboratory methods were employed to measure soil NO$ sb3 sp-$-N. A significant correlation was found between N-Trak and laboratory methods (R$ sp2$ = 0.61$ sp{**}$ for corn and 0.89$ sp{**}$ for wheat). Compared to the laboratory method, N-Trak overestimated soil NO$ sb3 sp-$-N. Soil NO$ sb3 sp-$-N levels increased upon drying. In some cases soils showed an increase in soil NO$ sb3 sp-$-N from seeding to postseeding. Wheat yields and wheat grain N uptake were better correlated with soil NO$ sb3 sp-$-N at seeding than at postseeding. For corn, yields and grain uptake showed a higher correlation with soil NO$ sb3 sp-$-N at postseeding. Corn regression models predicted 180 to 240 kg ha$ sp{-1}$ of N fertilizer to obtain optimum economic yields and 0 to 40 kg ha$ sp{-1}$ N for wheat. Soil total N was not correlated with corn yields as highly as soil NO$ sb3 sp-$-N. Soil NO$ sb3 sp-$-N can be used as an indicator of fertilizer N requirements for corn and wheat in Quebec.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.23415 |
| Date | January 1995 |
| Creators | Miransari Mahabadi, Mohammad Reza |
| Contributors | Mackenzie, A. F. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Natural Resource Sciences.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001488800, proquestno: MM12246, Theses scanned by UMI/ProQuest. |
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