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Response of corn, soybeans and cereals to sulphur application

Principal Investigator

John Lauzon

Research Institution

University of Guelph


April 2018 – March 2021


  • Determine the existence and extent of sulphur deficiency and yield response to sulphur fertilization throughout Ontario for corn, winter wheat and soybean.
  • Determine the maximum economic rate of sulphur fertilization for corn and wheat.
  • Collect and save soils from all experimental sites with associated yield data in anticipation of developing and calibrating a sulphur soil test in future work.


  • The collection of soil and associated yield data may lead to the future development and calibration of a sulphur soil test that would inform growers of the maximum economic rate of sulphur to apply for a given soil sulphur test result.
  • The determination of the extent and degree of sulphur deficiency and lost productivity across Ontario will allow for the development of best management practices to increase profitability and reduce input expenses in cash crop production.

Scientific Summary:

Application of sulphur fertilizer to corn and wheat has become commonplace in Ontario, even though the likelihood of increased yields is currently unknown. No soil test capable of predicting yield response from sulphur has been developed. Our previous research trials have shown benefits from sulfur in alfalfa and canola at around 25% of locations tested. Current sulfur recommendations for corn and wheat are based on non-replicated trials, anecdotal evidence, or the estimated of sulphur requirement due to reduced deposition of sulphur tighter sulphur emission standards in industry. In 2017, over 2 million acres where planted to corn, and 1.2 million acres to cereals in Ontario. Application of sulphur to these areas represents a large expenditure by growers with little scientific evidence of increased yield. The probability of response in corn and cereal crops is not known, but unlikely to be more than for the higher sulphur uptake crops.

This project will investigate sulphur response of corn, soybean and winter wheat grown in Ontario. We propose to undertake sulphur trials for three years meeting scientific criteria for evidence on corn grown after wheat, and cereals grown after soybean and soybeans grown after cereals using two studies. The first study will be at the Elora Research Station and have a range of sulphur rates range of sulphur rates (0, 10, 15, 20, 40 kg sulphur/ha) from ammonium sulphate together with another N source at rates that result in all treatments receiving the same fertilizer nutrients except sulphur. Soil samples will be collected at the time of fertilization and again approximately 3 weeks after planting to determine the soil sample timing that most accurately predicts the sulphur requirements of the crop. At harvest, yield, test weight, moisture, protein and sulphur concentration in both the grain and the stover will be measured. The second study will be on-farm trials with farmer-cooperators. Approximately 10 trials in corn, 10 in winter wheat and 5 in soybeans would be carried out in each of 3 years to determine the extent of sulphur deficiency across Ontario. These on-farm trials will consist of two treatments: no sulphur and sulphur applied at 40 kg sulphur/ha applied using the farmer’s standard fertilizer application methods. Information on the field site conditions will be collected at each on-farm trial including weather, soil type, slope, cropping history, manure application history. Soil samples will be taken around the time of fertilizer application. At harvest, yield, test weight, moisture, protein and sulphur concentration in both the grain and the stover will be measured. In addition, bulk soil samples from each study site in all years will be collected and stored for future greenhouse studies to measure plant sulphur uptake and develop a sulphur extraction process from soil that most closely correlates to plant uptake. Yield data from each of the sites where soil was collected will be used to determine the soil sulphur test level where a response to sulphur fertilization was seen.

External Funding Partners:

Ontario Agri-Food Innovaton Alliance, a collaboration between the government of Ontario and the University of Guelph