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Nitrogen management of fallow crops in Canadian prairie soils
- Karamanos, R. E., Selles, F., James, D. C., Stevenson, F. C.
- Canadian journal of plant science 2012 v.92 no.7 pp. 1389-1401
- Brassica napus, Triticum aestivum, bolting, canola, crops, fertilizer rates, grain yield, leaves, nitrates, nitrogen, normalized difference vegetation index, prairie soils, water use efficiency, wheat, Alberta, Saskatchewan
- Karamanos, R. E., Selles, F., James, D. C. and Stevenson, F. C. 2012. Nitrogen management of fallow crops in Canadian prairie soils. Can. J. Plant Sci. 92: 1389–1401. The ability of fallow to supply nitrogen (N) to crops has been questioned, particularly for crops with greater N requirements. A study was conducted to determine canola (Brassica napus L.) and wheat (Triticum aestivum L.) responses to a range of N fertilizer rates (0–75 kg N ha⁻¹ for canola and 0–50 kg N ha⁻¹ for wheat) at 17 fallow sites across Saskatchewan and Alberta, Canada, from 2003 to 2005. Yield and N uptake responses to progressively greater N fertilizer rates were curvilinear for both crops. Maximum yield occurred with 76 kg N ha⁻¹ for canola yield (2190 kg ha⁻¹) and 47 kg N ha⁻¹ for wheat (2910 kg ha⁻¹). Maximum N uptake occurred at about 90 kg N ha⁻¹ for both crops. Wheat grain yield and N uptake responses were mostly associated with normalized difference vegetation index (NDVI) at anthesis or flag leaf, whereas canola yields and N uptake were most associated with NDVI at five-leaf or bolting, or Cardy Nitrate meter at bolting. The preceding relationships were most apparent at the highest N fertilizer rates. Canola and wheat water use were not affected by N fertilizer rate, but water use efficiency increased linearly for both crops as N fertilizer rate was increased.