Pig slurry (especially pig slurry) is currently in the news and in the media due to the contamination it causes. mismanagement can cause and has caused in the past with the pollution of aquifers due to excessive percolations and inadequate doses of application.

Uncontrolled management and the bad practices of some heartless individuals have led to the criminalisation of an entire sector that works and carries out applications in accordance with current legislation, being singled out as the cause of pollution.

This situation means that, on the one hand, the various administrations are legislating with the aim of increasingly further increase the control of applications and the doses that are dumped on the land. On the other hand, the sector itself is seeking to do things better and better and to apply doses that not only do not exceed the maximum permitted doses but also meet the real needs of the crops, making the most of the slurry, not by treating them as waste but as a by-product which may have economic value as agricultural fertiliserThe price competition with mineral fertilisers (also a cause of groundwater contamination, but that is another story).

First of all, it should be made clear that slurry is nothing more than the faeces and urine of pigs (or whatever animal) and therefore it is not a toxic substance from chemistry but a product very similar to what we all deposit in the morning in our toilets.

It should also be clarified that the main difficulty in making a correct application in fertiliser units is due to the fact that 

the nature of the product itself with a lot of variability depending on the age of the animals, the time of the year (summer-winter), the type of feeding troughs, the type of animals (breeding or fattening), type of feed, ..., and so many others, which means that each farm and even each breeding farm has a different composition, so that general rules or average values do not help us to do things well.

Another factor that adds uncertainty to the system is the shape and treatment of the basin, if it has been homogenised (stirred) before and during loading, the composition of each basin will be very similar, if it has not been stirred, the first basins will have more liquid part with more dilution of water and less concentration of nutrients and vice versa with the last ones.

Once the situation has been presented, we are faced with the need to know if we want to know the exact" units of fertiliser that go into each vat to find a way to analyse each vat and estimate as accurately as possible the quantity of Nitrogen and other fertilisers carrying the cistern.

There are three main methods for analysing slurry

The complete nutrient content analysis (N-P-K) in the laboratory, repeated with each vat, would be the most appropriate method. This is very impractical and not at all operative, since if we wanted to know its content we would have to analyse the vat after loading it, and wait to receive the analysis, which means that we discard the laboratory directly since, as we have said, we want to make the application according to the richness, that is to say, already with the data, not knowing a posteriori what we have done.

The other method is the so-called rapid in situ measurement methods. There are methods on the market that are available to the farmer that allow him, with a good reliability, speed, simplicity and low costto know the ammoniacal N content of the slurry in each of the tanks, in order to optimise its dosage. These methods give a fairly approximate value but the farmer has to take a sample from each tank, mix it with reagents, carry out a small calibration process and wait a little time, which we do not see as very operative for continuous work and to evaluate each tank.

The last group of methods are the so-called estimation methods, which, based on a physical property of the slurry, by means of a statistical treatment of a multitude of slurry samples, obtains a mathematical model to estimate its nutrient richness. There are two main methods densimetry and conductivity. Densimetry is difficult to carry out in the field. Conductivity, on the other hand, is a physical quantity that, being applicable in industry, is highly technical with a multitude of commercial sensors that can be attached to the tank without major problems.

In view of the methods described above for the objective we have set ourselves of analysing each slurry tank, we have chosen as the best the measurement of conductivity using a conductivity meter installed in the tank and electronics that "translates" this conductivity value (normally expressed in milliSiemens) into a value of Kg of N/m3 that the farmer will be able to use for fertiliser.

At Agrointelligent we have developed AGROXCONTROL a platform for the control and management of slurry that analyses each vat by taking a multitude of values from the vat during transport from the farm to the field and by means of an algorithm determines very precisely the UFN/m3 contained in each vat of slurry and through its powerful software offers the farmer in real time the dose per hectare that it is applying both slurry volume and nitrogen fertiliser units. 

AGROXCONTROL also provides a estimation The system proposes a speed of advance to the farmer of the tractor-tanker or the lorry so that the dose applied is as close as possible to the real dose of the crop, which will prevent leaching, soil salinisation and other problems that tend to appear on plots where slurry has been applied for many years.

AGROXCONTROL also provides the farmer with a balance of fertilisers in the soil by means of a preliminary soil analysis, the actual estimation of kilograms of NPK provided by the slurry, and indicates to the farmer the possible deficiencies The fertiliser fertiliser is to be paid by means of chemical fertiliser, so that this fertiliser is not paid by eye and all the work of analysing and controlling the slurry is of no use in the end, as the fertiliser is not controlled by the slurry but by the chemical fertiliser.

In short, the best way for the intensive livestock sector, and the pig sector in particular, to stop being in the media spotlight is to take a more active role in the production and marketing of pigs. exhaustive control of its contributions and to prove (with the help of technology) that it is making responsible and correct use not of a waste but of a recovered by-product and there AGROXCONTROL is its best partner.