عنوان
پدید آورنده
موضوع
رده
کتابخانه
محل استقرار
TLpq304267707
انگلیسی
Development of a nitrogen soil test for fertilizer requirements for corn and wheat production in Quebec
[Thesis]
M. R. Miransari Mahabadi
A. F. Mackenzie
McGill University (Canada)
1995
127
M.Sc.
McGill University (Canada)
1995
One must consider the effects of both soil N and fertilizer N, if rates of N-fertilizer application are to be optimized and NO3\sp- leaching into groundwater be controlled. Objectives were (1) to determine soil usd\rm NO\sb3\sp-usd-N and NH4\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 NH4\sp+-N and NO3\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 NO3\sp--N. A significant correlation was found between N-Trak and laboratory methods (R2 = 0.61 for corn and 0.89 for wheat). Compared to the laboratory method, N-Trak overestimated soil NO3\sp--N. Soil NO3\sp--N levels increased upon drying. In some cases soils showed an increase in soil NO3\sp--N from seeding to postseeding. Wheat yields and wheat grain N uptake were better correlated with soil NO3\sp--N at seeding than at postseeding. For corn, yields and grain uptake showed a higher correlation with soil NO3\sp--N at postseeding. Corn regression models predicted 180 to 240 kg ha of N fertilizer to obtain optimum economic yields and 0 to 40 kg ha N for wheat. Soil total N was not correlated with corn yields as highly as soil NO3\sp--N. Soil NO3\sp--N can be used as an indicator of fertilizer N requirements for corn and wheat in Quebec.
Agronomy
Biological sciences
Soil sciences
Soil sciences
A. F. Mackenzie
M. R. Miransari Mahabadi
مطالعه متن کتاب p
[Thesis]
276903
a
Y
