By Ministry of Agriculture Staff
Livestock or poultry manure is a great source of plant nutrients for annual crops and perennial forages. Solid manures are also a source of organic matter that can have a significant, long-lasting effect on soil quality, resulting in increased plant growth. Liquid manures can have a similar effect, though to a lesser extent.
Knowing what you have, developing a long-term nutrient management plan, soil sampling and reviewing your application records will allow you to capture the value of the manure and minimize nutrient losses.
As such, manure can be a valuable addition for crop production. Here are five things to know about the benefits of manure.
- Nutrient content and balance
Not all manure is equal. The concentration of nutrients (N, P, K or S, micros) in manure can have considerable variation. This variation can occur from one farm to another, or even from one pen to another for ruminant animals. Quality and make of feed and rations, climate, quantity of bedding (if used) and a number of other factors will have an impact on the nutrients available. It is beneficial to have your manure tested to know the nutrient content and balance to best predict nutrient availability and any need to supplement with commercial fertilizer.
- Quantity of manure per animal
The application rate of manure to meet your crop requirements is based on the nutrients in the manure. The land area required depends on the quantity of manure produced. Records of the quantity of manure produced on your farm will provide the most accurate information for planning and for retaining a custom manure contractor, if one is used. If on-farm records are not available, contact the Ministry for average values based on published data and data collected from Saskatchewan farms.
- Commercial vs. organic phosphorus
Manure is a valuable source of nutrients and provides micro nutrients not applied as a commercial fertilizer. The concentration of nitrogen and phosphorus in the manure, however, is relative, may not be the ratio the crops require and may require decomposition of the manure before becoming available for plants to us. A quality manure management plan will include the use of commercial fertilizer to balance nutrient availability and requirements on a long-term basis.
Lab analysis of phosphorus contained in manure is reported differently than commercial inorganic fertilizer phosphorus. In manure analysis reports, manure phosphorus content is reported as weight of P per unit weight of manure, e.g. lbs P/ton of manure, while phosphorus content of commercial fertilizer is reported and sold on the basis of P2O5, e.g. percentage P2O5 by weight. The conversion is multiply P x 2.3 to convert to P2O5 equivalent, and multiply P2O5 by 0.43 to convert to P equivalent.
- Costs of spreading manure
The costs associated with loading, hauling and spreading manure can vary significantly. One custom operator in southern Saskatchewan identified the cost for loading, hauling one mile and spreading manure at $4.00/ton. A Saskatchewan feedlot indicated that a reasonable estimate is $7.00/ton based on hauling to a maximum of five miles.
Manure hauling and spreading costs need to be planned for and can vary significantly. Good plans and communication with a custom applicator or the staff responsible will help to minimize costs and avoid missing target crop lands.
- The economic benefit to your operation
It is possible to estimate an economic value of the manure used for plant growth. In an example calculation for feedlot manure, the value of nitrogen, phosphorus and sulphur was $7.30/ton. This was based on a four-year return period (four-year application rate) and average commercial fertilizer prices in spring of 2018.
If you are interested in measuring the nature and value of the manure from a particular operation, it is best to establish a farm record over a three-year period. Contact the Agriculture Knowledge Centre toll-free at 1-866-457-2377 for more information on sample collection and laboratory analysis.