A group of farmers in the Westlock, Alta., area trying some alternative forms of fertilizer — industry byproducts that might otherwise end up in landfills. These include elemental sulphur from petroleum product companies, wood ash from a local green power plant, and compost from Edmonton area landfills. They’re also trying hog manure, a rich nutrient source.
These farmers are clients of Geoff Doell, from Growth Agri-Coaching of Westlock. Iman Koeman, one of the farmer clients, has used all four of the products listed. Koeman isn’t an organic grower. He still uses commercial fertilizer at recommended rates. The alternative fertilizer sources are not meant to replace commercial fertilizers, but to supplement them.
Doell says reliable soil testing is imperative in knowing what product to use and how. Wood ash is helpful to raise soil pH while sulphur tends to lower it. Compost needs moisture to break down properly.
Elemental sulphur is a byproduct of the petroleum industry, removed to meet low sulphur emissions requirements. Some of Doell’s clients were buying discard sulphur (the bottom of the sulphur piles that weren’t clean enough to put in rail cars bound for China) from Semcans in Edmonton. Last spring when the price plummeted from $900 per tonne to $35 per tonne in one week, Doell encouraged his clients to purchase pure elemental sulphur prills by the rail car.
Not water soluble, elemental sulphur needs the contact with microbes in the soil to break down. “If elemental sulphur is applied and left on the surface of the soil for the first year, then the naturally occurring thio-bacillus bacteria populations will multiply up to one million times their numbers in a soil,” Doell says. Left on the surface for the first year, elemental sulphur will break down at 10 per cent per year. If incorporated right away, it is more likely to break down at one per cent per year, Doell says.
Koeman spread between 500 and 800 pounds per acre of elemental sulphur on his fields. He used his own fertilizer spreader for the lower rates and hired a commercial manure spreader for the higher rates. At 650 pounds per acre, sulphur cost him an average of $10 to $11 per acre (based on the $35-per-tonne price). The freight cost him $16 per tonne, or about $5 an acre based on his application rate. Spreading was another $4 per acre. The total was approximately $20 per acre.
One application at that rate is good for eight to 10 years. Using ammonium sulphate from an agricultural retailer, Koeman would annually use an average of 75 pounds per acre selling for $260 per tonne. That works out to about $9 per acre. Multiply that by eight years and you get $72 per acre compared to $20 per acre.
Most forms of elemental sulphur sold into the agriculture industry have bentonite clay mixed in to help make spreading more accurate, Doell says. Bentonite clay causes prills to swell, then break apart physically. This creates more surface area for the sulphur and microbes to do their thing. “The cost of the bentonite is about $200 per tonne more,” Doell says. This isn’t necessary if you use higher rates and spread sulphur on the surface, he says.
Sulphur can lower high pH, common in many soils northwest
Koeman was happiest with the hog manure, the benefits of which he could see for the next four or five years… He would be happy to take more manure when it is available.
of Westlock. “To free up some of the nutrients held tightly to the calcium complexes, we use elemental sulphur to drop the pH slightly,” Doell says. “This provides a long-term supply of sulphates for the plants and allows phosphorus, boron, copper, manganese, etc., to be more available from both the soil and from other fertilizer sources added.”
Lime is commonly used to raise soil pH. Wood ash is another effective liming material. In fact, the Government of Alberta Agriculture and Rural Development site (www.agric.ab.ca)says wood ash can be better than agricultural lime.
The same site says, “More than 180,000 tonnes of energy system wood ash produced annually at pulp mills, sawmills, oriented strand board and fibre board plants are currently disposed of in industrial or regional landfills.” It only makes sense to promote the use of this valuable resource to farmers instead!
Koeman got wood ash for free from a nearby green power plant burning wood chips. He just had to pay the freight. Koeman
spread the ash on his field with a fertilizer spreader.
In addition to raising pH, wood ash has many of the nutrients a plant needs with the exception of mainly carbon and nitrogen that are lost in the burning process. “Wood ash is primarily calcium, potassium and sulphur, with several other nutrients in ranging availability to growing crops,” Doell says. He adds that it is a significant source of zinc, “a great among the micros.”
More ash is not always better. Overliming can bring the soil into a high pH. Working with a good agrologist is important to choose the right lime source and amounts.
COMPOST AND MANURE
Farmers have used compost and livestock manure for centuries. Koeman used compost from an Edmonton composting facility on one of his poorer quarters last year. He wasn’t thrilled with the results, but thought part of the reason is that the weather was too dry to break down the compost into available nutrients. “I only put down (nitrogen) that comes with the phosphate and the 30 pounds that comes with the sulphur,” Koeman said. The resulting canola crop was light.
Koeman felt the price of compost was too high compared with commercial fertilizers. He paid $12 per tonne for the compost, $20 per tonne for freight, and $4 per acre to spread. Doell figures the compost is worth a total of approximately $40 per tonne compared to 2010 fertilizer prices.
The benefit will hopefully be an improved soil structure, lasting over several years. As Doell says, “With the careful addition of an alternative fertilizer source, the nutrient release rate is usually slower than commercial fertilizer sources so they can receive a nutrient benefit that lasts several years. Secondly, the impact the amendment has on the soil to allow the soil to be more efficient with other commercial nutrients added has both economic and environmental benefits.”
Koeman was the happiest with the hog manure, the benefits of
which he could see for the next four or five years. Although he found the application quite uneven, the benefits outweigh the problems. He would be happy to take more manure when it is available. His farm is conveniently close to several large commercial hog farms that have to empty their lagoons each fall.
“Animal manure contains most of the nutrients that crops require, including nitrogen, phosphorus, potassium, sulphur, calcium, magnesium, copper, manganese, zinc, boron and iron,” according to the Saskatchewan Ministry of Agriculture website at www.agriculture.gov.sk.ca.Not only does manure contain a tremendous amount of nutrients, but as organic matter it also improves soil structure, aeration, soil moisture holding capacity and water infiltration. Hog manure has the added benefit of a considerable amount of zinc, as hog feed usually contains zinc-oxide.
Koeman uses little or no extra nitrogen the first year after a hog manure application and a reduced amount the second year. Two years ago, his latest hog manure application, cost him $27 per acre banded into his field.
OTHER BYPRODUCTS WITH POTENTIAL
Other industry byproducts that show promise for agriculture are liquid lime, sewage sludge and pulp sludge. Liquid lime is produced in the process of making acetylene gas for the welding industry. Doell has used sewage sludge with his clients, but warns of possible problems — depending on what a town is flushing down its toilets. Pulp sludge, rich in nitrogen and carbon, has big potential if farmers are near a mill.
The world is becoming evermore environmentally sensitive and at the same time the need for food is growing. Using industry byproducts to increase yields and sustain soils only makes sense. As research continues in these areas we are sure to see more opportunities arise.
Marianne Stamm is a freelance farm writer from Jarvie, Alta. Email her at [email protected]