Pig manure is a liquid mass whose composition varies according to the type of pig farm. In addition to various organic elements, hair, faeces, urine, it also contains derivatives of nitrogen, phosphorus, potassium, but also calcium, magnesium, sodium, as well as trace elements: copper, zinc, manganese, iron, sulfur, boron, molybdenum, and sometimes synthetic materials (pieces of plastic, gloves, etc..) The main elements remain water, phosphorus, potassium and nitrogen.
Phosphorus in agriculture
In nature, phosphorus is more abundant in the form of phosphate compounds. These compounds combine mineral phosphorus (P) with oxygen (O).
These elements occur naturally in soils and their concentration varies according to the type of substrate. Only a fraction called bioavailable phosphorus is available to plants.
Phosphorus is an indispensable element for plants. It plays an active role in:
The development of plants: Nitrogen and phosphorus requirements evolve in parallel,
The development of the root network (root and rootlets),
The rigidity of plant tissues, with a beneficial effect on their resistance fungus diseases, and on their physical resistance
Fertilization and fructification
A non-eternal resource
According to several studies, such as that of Dana Cordell of the University of Linköping in Sweden, the world’s phosphate reserves will be exhausted within 50 to 100 years. The U.S. Geological Survey and the International Fertilizer Industry Association predict that phosphate reserves will be exhausted within 100 to 125 years. However, it is estimated that by the 2040s and 50s, phosphorus production will enter a period of deficiency.
Phosphorus issue – soil saturation
If more phosphorus is added than is removed from the harvested part of a crop, the soil is enriched with this element. One of the problems caused by the use of phosphorus in agriculture was its intensive use in the 1960s in certain regions, which over the years led to problems of soil phosphorus saturation with certain environmental consequences, particularly in terms of watercourses.
This problem leads to complex management of this element and regular monitoring of the evolution of the percentage of phosphorus saturation in the soil. In particular, it is necessary to determine the phosphorus reception capacity or surplus of each agricultural parcel under consideration and to manage the use of fertilisers (mineral and organic), including phosphorus, according to spreading plans.
This has organisational and financial consequences for pig producers whose farms are located in so-called saturation zones. Indeed, it is necessary to organize in order to find more and more distant receivers and to manage increasingly high operating costs, not to mention the carbon footprint caused by the transport of manure and its impact on the road network.
A pragmatic solution
Transporting slurry is expensive and large volumes are frequently involved. In addition, it must be stored in large pits that require a significant amount of land on the farm, and a spreading infrastructure (receivers, transportation, spreading) must be put in place. The further away the receivers are from the farm, the higher the operating costs. However, manure consists largely in… water.
Solugen treats the slurry by means of liquid/solid separation before treating the residual liquid. The result is a biosolid that represents 10% of the initial volume of the slurry and is very rich in phosphorus. 85% of the phosphorus in the slurry is found in the solid part. This makes phosphorus management much easier.
– drastic reduction in transport costs
– lower spreading costs
– better phosphorus management.