By: Darren Stovin, Provincial Environmental Engineer
How much is cattle manure worth? A recent study found that a tonne of manure from a feedlot contains about $13 worth of nitrogen, phosphorus and potassium (NPK). While the cost of manure spreading ($4 to $7) and the value of potassium ($6) could be discounted from this estimate, the value of manure is not limited to NPK.
Due to bedding and other organic matter, manure is known to improve the tilth of soil. This means that soil structure is improved along with the water infiltration rate and moisture holding capacity. Manure contains other nutrients that are required by crops, such as sulphur, calcium, magnesium and copper.
Recent studies have found that after manure application, yields in subsequent crops may increase by 20 per cent. This is in part due to the influence of micronutrients and organic matter.
Some nutrients in manure are not readily available to crops. It is probably necessary to top-up with commercial fertilizer, especially if manure is applied at moderate application rates. For example, only 10 per cent of the nitrogen in cattle manure is available to crops in the first year. This also means that nutrients will be released to crops for years to come. A typical yearly application rate is approximately 30 tonnes of manure per acre based on 50 per cent manure moisture content.
Properties of cattle manure vary greatly from one pen to another. Each truckload of manure will be very different, depending on the area from which it’s taken. For example, manure at the bottom of the bedding pack will be very wet, and it could have a moisture content as high as 70 per cent. Manure that contains a lot of bedding will probably have a moisture content closer to 35 per cent.
One truckload of manure could weigh twice as much as another, and some loads of manure will have more nutrient value than others. For this reason, it is best to look at the big picture. When the total amount of manure is considered rather than individual pens or loads, average values become more important.
For more information, check out our Economic Value of Beef Feedlot Manure fact sheet.