Cynthia Grant, Agriculture & Agri-Food Canada, Box 1000A, R.R.#3, Brandon, MB R7A 5Y3, Canada and Ronggui Wu, Agriculture and Agri-Food Canada Brandon Research Centre, Box 1000A, R.R.#3, Brandon, MB R0J 1E0, Canada.
Controlled release fertilizers can potentially reduce N losses and improve nitrogen use efficiency by synchronising N supply with crop N requirements. While a number of controlled release nitrogen products have been used in production of rice and other high value crops, they have been viewed as too costly for use in dryland agriculture. However, a lower-priced polymer coated urea product, “Environmentally Smart Nitrogen” or ESN, is now available that may be cost-effective for broad acre cropping systems.Field studies were conducted for three years at eight sites across Canada, to evaluate the effectiveness of ESN in improving crop yield and reducing N losses in a wide range of environments and cropping systems. Fall and spring banded ESN and uncoated urea were compared to split applications of urea for effects on crop yield, N uptake, N dynamics in the soil and losses by nitrous oxide emission and ammonia volatilization. Comparisons were made under reduced and conventional tillage. The polymer coated ESN and split N applications were both effective at increasing crop yield and N accumulation as compared to uncoated urea under wet conditions, but were less effective when conditions were dry. Wet conditions increase the potential for N losses by denitrification and leaching loss, increasing the benefit of controlled release and split applications. Nitrous oxide emissions and ammonia losses also tended to be lower with the ESN than with uncoated urea. Use of ESN or split applications can increase crop productivity and nitrogen use efficiency, while reducing N losses and negative environmental impacts in Canadian cropping systems. The economic benefits will depend on the environmental conditions, the potential for N losses, and the relationship between the cost of the fertilizer and the crop price received by the producer.
Back to Symposium--Use of Enhanced Efficiency Fertilizers for Improved Agricultural Nutrient Management
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Back to The ASA-CSSA-SSSA International Annual Meetings (November 12-16, 2006)
