Questions frequently asked about farm-based manure

Solid manure, liquid manure, slurry and compost made from manure at the farm are all included as farm-based manures.

Farm-based manures are a good source of nutrients. For any farming operation that produces and uses them, farm-based manures are the foundation of fertilization and soil maintenance programs. Farm-based manures act at the same time as fertilizers and as soil amendments and their characteristics vary according to type. Given that the chemical composition of farm-based manures vary greatly according to the type of manure, and from one farming operation to another, it is beneficial to undertake adequate sampling in order to fully assess the agronomic qualities of your own farm’s manure.

Sampling farm-based manures such as solid manure, liquid manure, slurry and compost

The value of the results of an analysis depends on the sampling quality. Samples submitted to the lab must be as representative as possible.

The sampling protocol for farm-based manures according to CRAAQ is a well-recognized method that enables, firstly, the determination of annual production of farm-based manure from a livestock facility and, secondly, the number of samples to be taken in order that the aggregate of collected samples properly reflects the quality of the farm-based manure. The results from an analysis of farm-based manure

The results of an analysis help to better understand the qualities associated with each type of farm-based manure. The analysis of the type of manure contains 10 physico-chemical parameters. In the following table, you will find an example of solid manure from dairy cows. The parameters of analysis are numbered and explained.

Parameters	Results	Interpretation
Dry matter (D.M.)	25%	Usually solid manure is 75% water, thus 25% is dry matter. By giving the % of D.M., we know on what basis the results of the analysis are indicated. At 25% D.M., this is a result on an ‘as is’ basis. Therefore you don’t need to do any conversion to use the results.
Total nitrogen (N tot)	5,5 kg/tonne	In each tonne, there are 5.5 kg of nitrogen. If you apply 30 T/ha, you will have applied 165 kg of N/ha. This is a raw amount of nitrogen and not what will be available to crops.
Ammonia nitrogen (N-NH4)	1,5 kg/tonne	In each tonne, there is 1.5 kg of N-NH4. This nitrogen is readily available to crops once the manure is spread.
Phosphore P2O5	3,8 kg/tonne	In each tonne, there is 3.8 kg of P2O5. P2O5 is the form under which phosphorus fertilization recommendations are developed.
Potash (K2O)	5,4 kg/tonne	In each tonne, there is 5.4 kg of K2O. By transforming potash in the form of K2O, it is easier to make fertilization calculations; K2O is the form under which potash fertilization recommendations are developed.
C/N ratio (Carbon/nitrogen)	16	The C/N ratio gives us an idea of the fiber found in manure: the higher the C/N ratio, the more fibrous the manure; manure with a lot of straw could have a C/N ratio of 22-23; liquid manure from cattle could have a C/N ratio of 10-12. The more fibrous the manure, the more time it takes the nitrogen to be released; this data will have a great influence on determining the best spreading dates. .
Organic matter (OM)	85 %	This data means that 85% of the dry matter in the manure is made up of organic material, the rest being made up of minerals (N, P, K, Ca, etc.)
pH	6,9	The pH tells us the manure’s acidity.
Ca (calcium)	1,8 kg/tonne	In each tonne, there is 1.8 kg of calcium.
Mg (magnesium)	0,6 kg/tonne	In each tonne, there is 0.6 kg of magnesium.

Farm-based manures have good fertilizing value.

The nutrients contained in the manure become available to crops once the manure is spread and as soon as it starts to decompose in the soil.

According to the type of manure, the spreading dates and the speed with which the manure is incorporated into the soil after being spread, there will be more or less nutrients available to crops. The fertilization value of farm-based manures is thus calculated from several coefficients of efficiency that depend on spreading dates and the delay in incorporating the manure into the soil.  

As for nitrogen efficiency, it also depends on the C/N ratio for farm-based manures. In general, the more the manure is fibrous and contains straw, the less nitrogen is available for crops.

All the NMPs prepared by Logiag take into account the best information available on farm-based manures to calculate the amount of N, P2O5 and K2O available for crops.

This question comes up often. How much is a round of manure spreading worth? Unfortunately, the answer is not simple. Can you place a value on organic matter? Minor elements? How will the manure be managed and what percentage of nutrients will actually be available to the crop? In your region, is there an excess or deficit of farm-based manures? Are you a receiver or a supplier of manure? And how much does the equivalent in fertilizer purchased from your input provider cost?

At Logiag, we have developed a small piece of software that takes into account several factors to evaluate the value of a round of spreading farm-based manure. Learn more from the expert advisors in our network.