Residual Soil Nitrate after Potato Harvest
- Gilles Bélanger *a,
- Noura Ziadia,
- John R. Walshb,
- John E. Richardsc and
- Paul H. Milburnd
- a Agriculture and Agri-Food Canada, Soils and Crops Research and Development Centre, 2560 Hochelaga Boulevard, Sainte-Foy, Québec, Canada G1V 2J3
b McCain Foods Limited, 317 Main Street, Florenceville, New Brunswick, Canada E7L 3G6
c Agriculture and Agri-Food Canada, Atlantic Cool Climate Crops Research Centre, Brookfield Road, P.O. Box 39088, St-John's, Newfoundland, Canada A1E 5Y7
d Agriculture and Agri-Food Canada, Potato Research Centre, P.O. Box 20280, Fredericton, New Brunswick, Canada E3B 4Z7
Nitrogen loss by leaching is a major problem, particularly with crops requiring large amounts of N fertilizer. We evaluated the effect of N fertilization and irrigation on residual soil nitrate following potato (Solanum tuberosum L.) harvests in the upper St-John River valley of New Brunswick, Canada. Soil nitrate contents were measured to a 0.90-m depth in three treatments of N fertilization (0, 100, and 250 kg N ha−1) at two on-farm sites in 1995, and in four treatments of N fertilization (0, 50, 100, and 250 kg N ha−1) at four sites for each of two years (1996 and 1997) with and without supplemental irrigation. Residual soil NO3–N content increased from 33 kg NO3–N ha−1 in the unfertilized check plots to 160 kg NO3–N ha−1 when 250 kg N ha−1 was applied. Across N treatments, residual soil NO3–N contents ranged from 30 to 105 kg NO3–N ha−1 with irrigation and from 30 to 202 kg NO3–N ha−1 without irrigation. Residual soil NO3–N content within the surface 0.30 m was related (R 2 = 0.94) to the NO3–N content to a 0.90-m depth. Estimates of residual soil NO3–N content at the economically optimum nitrogen fertilizer application (Nop) ranged from 46 to 99 kg NO3–N ha−1 under irrigated conditions and from 62 to 260 kg NO3–N ha−1 under nonirrigated conditions, and were lower than the soil NO3–N content measured with 250 kg N ha−1 We conclude that residual soil NO3–N after harvest can be maintained at a reasonable level (<70 kg NO3–N ha−1 ) when N fertilization is based on the economically optimum N application.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 2003.