Tuesday, 7 October 2008: 9:00 AM

George R. Brown Convention Center, 360F

Guy Lafond¹, Chris B. Holzapfel², Byron Irvine³, Malcolm, J. Morrison⁴, Dean James⁵ and William B. May¹, (1)Agriculture and Agri-Food Canada, Indian Head Research Farm, RR#1 Gov. Rd, Box 760, Indian Head, SK S0G 2K0, CANADA
(2)Indian Head Agricultural Research Foundation, RR#1 Gov Road, Box 156, Indian Head, SK S0G2K0, Canada
(3)Agriculture and Agri-Food Canada, Box 1000a Rr #3, Brandon, MB R7A 5Y3, CANADA
(4)Eastern Cereal and Oilseed Research Centre, Agriculture and AgriFood Canada, Central Experimental Farm, 960 Carling Ave, Ottawa, ON K1A 0C6, Canada
(5)AAFC – Semiarid Prairie Agricultural Research Centre, Airport Road #1, P.O. Box 1030, Swift Current, SK S9H3X2, Canada

Nitrogen is the most limiting nutrient to crop production on the Canadian Prairies. Of the four factors encompassing nitrogen management, form, timing, placement and rate, deciding on a rate of nitrogen is the most challenging because of the spatial and temporal variability of crop nitrogen requirements and the soils capacity to supply N. Studies were established to develop appropriate algorithms for the GreenSeeker^tm optical sensor in spring cereals and to then test the algorithms in separate but adjacent areas. Yield potentials were generated using different rates of nitrogen and sensor values were related to final grain yield using an exponential function, y=a*exp b*x where y=grain yield and x=(sensor readings-NDVI divided by growing degree days from planting to sensing using a base temperature of 0^oC). The crops of interest were spring wheat, durum, oat and barley. The algorithms for each crop were then evaluated for their ability to manage nitrogen relative to uniform rates of nitrogen applied at time of planting in the soil. The risks of in-crop applications of nitrogen were also determined as part of the test treatments. The study supports the merits of in-crop N applications for all crops measured. Post-emergent N applications, when combined with optical sensors, offers the possibility of refining N rates to match the crop with soil and crop conditions and to also take into consideration spatial variability in soil nitrogen.

See more of: Tools for Improving Nitrogen Management
See more of: S04 Soil Fertility & Plant Nutrition

2008 Joint Annual Meeting (5-9 Oct. 2008): Potential for Fine-Tuning Rates of Nitrogen Using in-Crop Applications of Nitrogen Based on Greenseekertm Readings in Spring Cereals on the Canadian Prairies.

671-3 Potential for Fine-Tuning Rates of Nitrogen Using in-Crop Applications of Nitrogen Based on Greenseekertm Readings in Spring Cereals on the Canadian Prairies.