GHGMP Project Reports by Region

Soil tests will help Nova Scotia producers fine tune nutrients

Despite cool, wet conditions there is a way to better match fertilizer and manure rates to crop needs

This summer Nova Scotia producers will have another look at how to better manage nutrients to improve crop production economics and benefit the environment at the same time, says a provincial soils specialist.

The value of soil tests in fine tuning nitrogen fertilizer application rates, and the timing and application methods for applying manure, will be the focus of a number of on-farm demonstration projects across the province, says Rob Michitsch, program co-ordinator of the Greenhouse Gas Mitigation Program for Canadian Agriculture (GHGMP).

"The goal is to reduce the amount of nitrogen used in crop production," says Michitsch. "The soil test demonstrations will show how we can get as good or better yields through improved nitrogen management. These practices will help improve crop economics and will also be resource conservation measures that are good for the environment because they reduce the potential for nitrous oxide emissions (a potent greenhouse gas)."

The cool, and often wet, growing conditions of the Nova Scotia climate have been key factors discouraging producers from using nitrogen soil tests over the years, says Michitsch. Fall soil test recommendations, for example, often weren't relevant by seeding time because soil nitrogen levels changed over winter.

Nitrogen tests

As part of the GHGMP demonstrations, techniques such as the pre-sidedress soil nitrogen test (PSNT) in corn and the pre-plant nitrogen test (PPNT) in grain, are being evaluated. These tests, performed just before nitrogen is applied, can help producers fine-tune and likely reduce nitrogen rates, says Michitsch.

"Traditionally, producers follow standard nitrogen fertilizer application rates," he says. "While it does the job, research shows that usually, more nitrogen is applied than is needed by the crop, or it is applied at the wrong time. Through improved management and use of these soil nitrogen tests, we can improve efficiency by targeting the proper amount of nitrogen to crop needs."

Demonstration trials over the 2003 and 2004 growing season show that less than the standard recommended rates will produce high quality yields, says Michitsch. Some demonstration plots treated with varying fertilizer rates showed that 50 percent of recommended fertilizer rates produced yields equal to the full-recommended rate.

"Results from the past two years indicate producers do not need to apply nitrogen at 100 percent of the recommended levels to obtain similar, high quality yields," says Michitsch. "We also found that higher greenhouse gas emissions, on-farm time requirements and related expenses, were also associated with higher nitrogen rates." Similar trials will be conducted on corn, grain, forages, vegetables, and organic horticulture crops during the 2005 growing season.

More isn't better

Over-application of nitrogen is a waste of money, and negatively impacts the environment. Nitrogen left in the soil can leach away over winter and during heavy rainfall. It can also be lost to the atmosphere through a process known as denitrification. Nitrate remaining in the soil can be converted to nitrous oxide, which is one of the more serious greenhouse gases.

The federal Greenhouse Gas Mitigation Program for Canadian Agriculture introduced in 2001, is designed to demonstrate, over a five-year mandate, a wide range of improved management and production practices that benefit production, and reduce greenhouse gas emissions.

The soils and nutrient management areas of the GHGMP program are administered through the Soil Conservation Council of Canada and delivered through a network of provincial committees known as Taking Charge Teams, which are made up of producer, industry, government agrologists and research representatives. More information on Nova Scotia projects can be found on the SCCC Website at: www.soilcc.ca.

Manure projects

In related work, other Nova Scotia demonstrations will evaluate the seasonal timing of manure applications, as well as different manure application technologies, says Michitsch.

Demonstrations in 2004 compared the release of nitrous oxide and ammonia from manure during spring and summer applications, as well as early and late fall applications. While the data is still being analyzed, Michitcsh will monitor similar plots in 2005.

"Since soil temperature is a factor in converting nitrogen into nitrates, nitrous oxide and ammonia, we want to see if we can retain nitrogen in the soil by delaying application of manure until the soil cools to a point where conversion is slowed," he explains.

New manure application technologies, such as liquid manure injection, will be evaluated to determine the effect on release of odour, and levels of nitrous oxide and ammonia. "We'll also be looking at the effect of manure injection on soil productivity, soil quality and yield response, using different rates of nitrogen fertilizer, all under Nova Scotia conditions," says Michitcsh.

"Preliminary results from 2004 demonstrations indicate that injection increased levels of nitrous oxide emissions, but decreased ammonia emissions," he says. "We will be repeating the evaluation this year."

For more information on related projects also visit the Soil & Crop Improvement Association of Nova Scotia website at: www.scians.org.


Regional reports will be posted as information becomes available. Please check back regularly for updates.