Source: Government of Alberta
“It is difficult to place a value on the organic matter and erosion considerations of straw,” says Neil Blue, provincial crop market analyst with the Alberta government. A 30-year study was completed at the Agriculture Canada farm at Indian Head, Saskatchewan in the Black soil zone. “This study of a wheat-wheat-fallow rotation indicated that continuous removal of above-stubble straw had no effect on yield,” adds Blue, “but did reduce the soil’s ability to convert organic carbon to carbon dioxide and reduced the stability of soil aggregates, which is required for maintaining soil structure and preventing erosion.”
Other studies, however, indicate that the values of organic matter and erosion prevention are more apparent in the Brown, Dark Brown and Grey-wooded soil zones. An estimated one-half to two-thirds of the total plant material is removed from a field during baling. A significant amount of material remains as stubble, chaff and root system. “The conclusion is that straw in the ground can provide long-term economic gain, while baled straw can provide short-term economic returns,” says Blue.
Nutrient content of straw types varies widely in samples taken and climatic factors appear to be the main cause of this variation. Fertilizer costs can be used as a source for valuing some of the nutrient contents of straw, including nitrogen, phosphorus, potassium and sulfur.
Table 1. Fertilizer values (subject to market changes)
Using fertilizer-based values for these major nutrients in straw, and baling costs of about $14/large round bale, a 1000 lb. wheat straw bale would be worth $17.70 (in the swath) + $14 (baling cost), or about $32/bale in the field. Hauling costs approximate $5/bale, depending on distance. Taking hauling into account, a 1000 lb. wheat straw bale, in the yard, would be worth about $37/bale. Using comparative average nutrient values, a $37 value for a 1000 lb. wheat straw bale implies an “in the yard” value of about $39/1000 lb. barley straw bale, and about $42/1000 lb. oat or pea straw bale. Whether differences in sale value between types of straw occur is up to the market.
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