KEY PRACTICE: Predicting how much nitrogen is reserved in the soil is difficult. Given its high cost in canola production, conducting an annual soil test on each field to
determine appropriate rates is a good idea. The wild card is moisture supply throughout the growing season.

PROJECT TITLE, LEAD RESEARCHER: “Long-term effects of different soil test based fertilizer rates on crop production, contribution margin, and soil quality in the Peace region.” 2009-12, Kabal Gill, Smoky Applied Research and Demonstration Association (SARDA)

GROWER ORGANIZATION FUNDER: Alberta Canola, MCGA, SaskCanola

Nutrient carryover has a major effect on crop yield. In order to predict recommended fertilizer rates, an annual soil test is wise. Testing for nitrogen (N) levels helps, but this study did not show a benefit to testing for phosphorus (P), potassium (K) and sulphur (S) every year. Recommended rates for these were the same each year.

SARDA’s objectives were to study the long-term effects of different soil-test based fertilizer rates on crop production, and whether soil testing can detect the effects of different fertilizer rates in previous years. Fertilizer rates were applied at zero, 60, 80, 100, 120 and 140 percent of the recommended rate through the four-year study. The same fertilizer rate was applied each year in a given plot to demonstrate the long-term effects. The study used a wheat-canolabarley- pea rotation, with all four crops grown every year. The study was done in the Peace River region with no tillage.

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Tags: nitrogen