Bright Future for Solid Manure Injection

CANADA - Research conducted by the University Saskatchewan suggests a promising future for solid and semi-solid livestock manure fertilizer injection technology. Researchers with the university’s Department of Crop Science have released preliminary results of a three year study examining the agronomic and environmental implications of solid manure injection.
calendar icon 1 November 2008
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The study, which began in the spring of 2007, looks at crops grown on land fertilized with solid cattle manure applied using a prototype sub-surface applicator designed by the Prairie Agricultural Machinery Institute (PAMI) at Humboldt, Saskatchewan.

Several Solid Beef Manure Fertilizer Treatments Under Evaluation

The research, which compares a variety of manure treatments to an unfertilized check, is being conducted near Humboldt on “a loamy black chernozemic“ type soil.

“What we’re looking at are three different rates of solid cattle manure; and three different applications, injected, broadcast and incorporated and broadcast,“ says Dr. Jeff Schoenau, a research scientist with the University of Saskatchewan’s Department of Soil Science. “We also have a treatment where we have injected cattle manure combined with urea fertilizer.“

“We’re looking at the effect of the different rates and the different placements and the different combinations on crop yield, crop nutrient uptake, soil nutrient levels and distribution. And we’ve also been looking at the effect of the different treatments on nutrient accumulation on the soil surface and nutrient runoff potential,“ he explains.

Development of the implement began at the University of Saskatchewan in 2001. Following the completion of a bench scale prototype, the project was turned over to the Prairie Agricultural Machinery Institute to apply the technology to the field.

Equipment Designed to Handle Various Manures and Organic Waste Streams

“The system was designed to work with anything that is not pumpable,“ says PAMI project leader Dr. Hubert Landry. “Typically we’ve been working with beef cattle manure but really, the product could come from any type of livestock production or even other by-products like municipal sludge.“

The machine uses a series of discharge screw conveyers to auger manure to flexible injectors which deliver the material to coulters that open trenches in the ground into which the manure is deposited and the trenches are then closed.

Dr. Landry describes the implement as a trailer with a large hopper that contains the products to be land applied. At the bottom of that hopper there are four discharge screw conveyers. The screw conveyers move the product to the rear of the machine where it falls into a transfer distribution conveyer for distribution along the width of application, perpendicular to the direction of travel, to coulter openers. The coulters open a trench into which the material is deposited and the trench is then closed.

“We really are doing sub surface application with that equipment,“ says Dr. Landry.

Technology Ready for Commercialization

Dr. Landry notes, “From a mechanical point of view, we would be fairly close to being able to go to market.“

However he acknowledges. the agronomic and environmental benefits of the technology are not yet proved.

“We really need to look into those aspects before we can really foresee a market application.“

Preliminary Observations Encouraging

Preliminary results from the first two years of field trials are encouraging. In year one of the study, 2007, researchers planted oats and in year two, 2008, canola was planted.

“So far, in 2007 and 2008, we didn’t see really much difference between the different placements of the manure in terms of effects on yield whether it was broadcast, broadcast-incorporated or injected.“

However, considering the material applied, solid cattle manure, didn’t contain a lot of immediately available nutrient, the team wasn’t surprised.

Dr. Schoenau notes, while there was some yield response to the manure additions in both years, there was not a great difference according to placement.

“We found our highest yields where we combined urea fertilizer with the manure that was injected. I think that can be attributed to the fact that the solid cattle manure has pretty low nitrogen availability in the year of application. The addition of the supplemental urea fertilizer really helped in terms of increasing the supply of nitrogen and actually helped the crop use the phosphorus that was being applied with the manure as well.“

Environmental Benefits Also Observed

As for the environmental implications, Dr. Schoenau continues, “We’ve also been looking at the effect of the different placements on the stratification of nutrients. That is the accumulation of nutrient close to the surface. The data we’ve looked at so far this year has been showing that the broadcast and incorporate and the injected is indeed lowering the concentration of available or what you might call potentially mobile phosphorus at the surface of the soil.“

Novel Injectors Key to Design

“The injection part of the equipment is what’s import because it’s novel,“ says Dr. Landry.

The equipment brings uniformity of distribution as well as a very good control of the rate of application of manure.

“This is a great improvement over what is commercially available as far as equipment,“ he says.

The University of Saskatchewan study is scheduled to continue for one more year. Dr. Schoenau says researchers have also collected mona LISS of soil and have been doing simulated run-off from those mona LISS.

The data from that work is still being analyzed.

“We’ll have a pretty good idea, in about a year’s time, in terms of the effect of this application strategy on crop response, soil conditions and also nutrient run-off potential.“

Wide Ranging Benefits Identified

Dr. Landry is convinced, when the uniformity of application and the level of control over the rate are considered, the advantages are clear.

“You can easily see the benefits of having controlled amounts of nutrients for the farmers to recycle those by-products into a valuable source of nutrients. They would know how much they are applying and where they are applying it in the field. From the producer point of view you get a good source of nutrients and then from the livestock industry you get an outlet for that by-product that you have to deal with.“

Dr. Schoenau notes, “The information that we collect from the agronomic and the environmental side will be useful to ascertain the degree to which placement of solid manure in the soil helps to improve nutrient recovery and helps to mitigate the potential loss of nutrients from the system by run-off. We hope our results will ultimately end up being used to develop better recommended beneficial management practices for growers.“

“The manure has to go somewhere,“ Dr. Landry concludes, “So we can see the benefits on both sides.“

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