The results from a southern Alberta research study are now being used to promote best management practices for safe application of manure to soil. Landowners, industry, government agencies and the general public can use this information to understand manure issues and make good manure management decisions.
In 1993, researchers at Lethbridge launched a multi-year, two-site study to assess the effects of various manure application rates on soil and groundwater. The study included two identical sites in the Picture Butte area, one on a sandy soil and the other on a loam soil.
The study recommends that repeated annual application rates of cattle manure be less than 60 t/ha (at 50% moisture content) in the short term (3 to 5 years), particularly on coarse-textured, irrigated soils over shallow groundwater. However, much lower rates (20 t/ha) or less may be required if repeated annual applications are continued over a longer period (5 to 10 more years).
Several extension activities are underway to make the study results available to a wide audience. "We’ve developed two factsheets focusing specifically on the effects of manure on soil and groundwater quality, and manure nutrient management," explains Dr. Barry Olson, Research Scientist with Alberta Agriculture, Food and Rural Development (AAFRD) in Lethbridge. These two bulletins are part of a series of eight bulletins on soil and water resource management, published by the Irrigation Branch.
"I've summarized Olson's study results for producers, and included it in the AESA annual report," says Troy Ormann, AESA Soil Conservation Technologist and GIS Coordinator for the County of Lethbridge. The full report is included in the appendix. "We make this report available at tradeshows and other events, plus we send out between 40 and 50 copies to meet requests from producers, college and university students," he adds.
The study results provide a good stepping stone to explain what producers can do to prevent over-application and other general concepts of manure nutrient management. The key is knowing what is in the manure, knowing what the land really requires for nutrients, and applying appropriately.
Ormann has included the study sites on field tours for farmers and municipal representatives. And both Ormann and Olson have made presentations on the study to farmers, scientists and others. Says Olson, "When speaking at farmer meetings, we present some of the results of the study. These data show what happens if you over-apply manure in terms of nutrient accumulation, especially of nitrogen and phosphorus, in the soil and in shallow groundwater."
"The high-end producers in my area are conscientious businessmen who are interested in managing manure nutrients properly," says Ormann. "These study results provide the information to help them meet the environmental criteria for applying manure safely to protect soil and water resources." Some of these producers are participating in other similar projects initiated by AAFRD and the County of Lethbridge. This project is sponsored in part by the Alberta Environmentally Sustainable Agriculture (AESA) Program.
"We've also generated interest from other researchers, who are using the sites for sampling both soil and groundwater," says Olson. The sites are currently part of a nine-site provincial manure study led by the Alberta Research Council. "We're participating by providing special soil samples for specific components like phosphorus, that are required for developing a model," he adds. Olson also plans to continue his research at the two sites for at least two more years.
For more information, contact Barry Olson or Troy Ormann. |