Although a large share of Canada's soil nutrient needs could be supplied by manure, limited supply and problems with distribution and lack of consistency of quality mitigate against its widespread use, except in certain regions of eastern Canada. Also, storage of manure is a problem in terms of potential environmental pollution and loss of quality over time. Manure can vary widely in its nutrient and organic matter content, so it is sometimes difficult to determine how much manure should be applied. Adding manure to soil can also introduce unwanted items, like weed seeds, bacteria, and toxic chemicals. The prairie provinces report the lowest use of manure in Canada, while British Columbia and Central and Atlantic Canada report higher manure use.
Manure is spread on cultivated land mainly as a way of disposing of farm animal waste.
Land application of manure is high in regions where farm animal production is high and the manure can be collected and distributed easily. Manure use is lower in areas where production of manure is low or distribution is difficult. For example, in the Prairies, cattle are concentrated only in certain areas, and fields are large and require large amounts of manure for complete coverage. Beef farms are not suited for land application of manure, except from cow-calf operations and feedlots. Manure in British Columbia and central and eastern Canada comes mostly from dairy and poultry farms, which are numerous and scattered throughout crop production regions.