December 15, 2022

And you call this waste? The agronomic value of manure

Animal waste can be a source of organic matter and nutrients, and whether in its natural form or various transformations, it can benefit the chemical, physical and microbiological fertility of cultivated land. Manure, above all, has particularly interesting characteristics from an agronomic point of view, which is why it’s used as a soil conditioner and to create organic fertilizers and organo-minerals.

What is manure?

Manure is the result of fermentation carried out by various microorganisms on a mixture of animal waste (solid and liquid) and litter, which may consist of materials from various origins: straw, corn stalks, peat, marsh herbs, wood sawdust…

The composition of manure varies greatly depending on a number of factors.

  • The domestic animal that produced the waste, age and diet: the more the animal is able to absorb nutrients from the food that is being fed, the poorer the manure. Cattle manure displays the most interesting compositional characteristics and is therefore the most used in the production of organic and organo-mineral fertilizers. However, horse manure and sheep manure are also quite interesting, especially for being rich with nutrients, while poultry manure (chicken manure) has a high content of organic matter. Pig manure is more difficult to use: due to it’s composition, which is very rich in urine and therefore excessively liquid, it tends to acidify the soil.
  • Type of litter used. This influences the final chemical composition of the product both directly and indirectly: in fact, different litters show different imbibition capacities, which determine a different retention of urine, simultaneously influencing the greater or lower rate of fermentation of the mass. Cereal straw, for example, absorbs rather easily and is rich in potassium, but low in nitrogen and phosphorus.
  • Timeline and methods of manure maturation. Back in the day, maturing manure simply meant placing it in heaps and waiting for the fermentation processes to start spontaneously, which in the time span of a few months transformed it into material ready to be distributed in the field. Today, producing manure as a raw material for high-performance fertilizers means carefully managing the entire supply chain, starting with animal husbandry.

 

What does manure contain?

As previously mentioned, manures have different compositional characteristics depending on their origin. However, in general, if the maturation process has taken place correctly, they contain humidified and stable organic matter, capable of improving the structure of the soil, and  nutritional elements (macro, meso and micro). The latter will be transferred to the circulating solution following mineralization, more or less slowly depending on the environmental conditions occurring after distribution (temperatures and rainfall, in particular) and the level of microbiological viability of the soil.

Below are some compositional data taken from the Hoepli “Agriculture Manual”.

Average production and quantity of fertilizer elements found in the manure of various animals.

Animal

Production

q/year

% on sample as is
N P205 K2O CaO
Cattle 125 – 180 0,4 0,2 0,5 0,5
Horse 80 – 120 0,6 0,3 0,5 0,3
Swine 12 – 18 0,5 0,2 0,6 0,1
Sheep 5 – 7 0,8 0,2 0,7 0,3
Poultry 0,6 – 0,8 1,7 1,6 0,9 2,0

 

Chemical composition of cattle manure. Average values expressed in % on sample as is.

Manure Dry Matter N P205 K2O CaO MgO SO3
Fresh 25 0,4 0,20 0,6 0,45 0,15 0,1
Manure 20 0,5 0,25 0,7 0,55 0,2 0,15

 

Manure in Agribios Italiana products

As amply discussed in our Special ORGANIC MATTER, manure is the best choice for providing organic matter to the soil.

Agribios Italiana’s organic and organo-mineral fertilizers and conditioners contain different types of manure, produced exclusively on farms certified for the adoption of husbandry techniques aimed at guaranteeing animal welfare.  This makes it possible to classify the resulting matrix as Organic.

The temperatures reached during manure fermentation eliminate any pathogens that may be present and devitalize weed seeds. Natural drying, without the use of ovens, which allows slow humidification and the simultaneous achievement of chemical-physical and microbiological parameters optimal for subsequent use in formulation, makes it possible to maximize the qualitative potential of the starting materials.

Finally, the inoculation with useful microorganisms before the pelleting phase completes the stages of the process, designed to generate products with biostimulant functions and biocontrol.

 

Manure generates circular economy and... art

As reported by various Italian dictionaries, the noun “manure” derives from the Latin laetamen, in turn derived from laetare (fertilize), from “laetus” in essence “glad”, but originally “fertile”.

A waste of livestock supply chains, which for centuries (but according to some sources already since the Neolithic Age, or between 8000 and 3500 years BC) has been reintroduced into the production cycle of agricultural crops: manure is in fact a virtuous example of circular economy, even if its value in agriculture was recognized long before economists and ecologists coined this term.

In addition to being a soil conditioner and fertilizer, manure is used in the production of biogas, solid fuel and substrate for the cultivation of edible mushrooms.

But there’s more: there are those in Piacenza who have developed a process for using it to obtain a material similar to terracotta, thus producing furnishing pieces and accessories, surrounded by a museum, educational activities and exhibitions.

 


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