The pig farm in Poland has held its first secure dispersion of manure

Author: BalticSea2020
Year published: 2016

After several years of preparation and planning, the Przybkowo pig farm in Poland has undertaken its first secure dispersion of manure onto its farmland. Using a methodology that safely treats, stores and distributes manure, the farm has taken its first step towards its goal of reducing leaching of the nutrients phosphorus and nitrogen into the Baltic Sea.

In 2010, BalticSea2020 began a long-term research and action programme in order to identify the technologies and methodologies that can be used to minimise the risk of leaching of nutrients (phosphorus and nitrogen) from manure. Following an extensive investigation begun in 2013, a large-scale demonstration project was launched in collaboration with the industrial pig farm Przybkowo, one of Poland's three largest pig producers, with an output of around 30,000 slaughter pigs per year and with arable land totalling approximately 800 ha. Previously, the farm lacked a system that could safely dispose of the approximately 66,000 m3 of manure produced annually. Proper management of manure can reduce nutrient leaching, while at the same time, the material becomes a benefit to the farm. In late October, using the new equipment, the first secure dispersionof manure was conducted and the hope is that the 2017 planting season can be fully implemented within the framework of the project.

The road to secure dispersion of manure
The first stage of the project involved an examination of how much phosphorus and nitrogen was being produced by the pig farm. With that information, it was possible to determine how the farm's manure could be optimally pre-treated, stored and dispersed. The total annual amount of manure contained (in untreated form) 71 tonnes of phosphorus and 235 tonnes of nitrogen. The project's goal is to spread no more than 22 kg of phosphorus and 170 kg of nitrogen per hectare, per year on the farmland.

For there to be the possibility of managing these quantities of manure and of attaining the target for the amount of phosphorus and nitrogen to be spread on the fields, the farm needs to separate out the phosphorus and prevent the nitrogen from leaving the manure in the form of ammonia (GHG). The objective is to collect the maximum amount possible of all the phosphorus in a dry fraction and the maximum amount possible of all the nitrogen in a wet manure fraction.

The dry manure fraction has a consistency akin to that of peat, which makes it both easy to handle and transport away from the farm. This part of the manure can be used, for example, asa soil improvement agent for agriculture or private households. The wet fraction of the manure is pumped through a separator to large, 600 m3tanks. Here, it is stored for a few days for the phosphorus to collect on the bottom. When its phosphorus content is thus reduced, the wet manure fraction is then pumped into a bulk liquid transporter and taken on to the large storage lagoons. There are four of these altogether, each having capacity for 15,000 m3 of manure (see picture below). The wet manure fraction is kept here to be later dispersed ontothe farm’s arable land when appropriate.

The manure fraction is stored in large storage lagoons. There are four of these altogether, each having
capacity for 15,000 m3 of manure. Photo: BalticSea2020.

The wet manure fraction also goes on to the so-called “manure acidification” process. By adding small amounts of sulphuric acid to the manure, its pH value is reduced (it becomes more acidic) and this also changes its nitrogen content from the volatile ammonia (NH3) gas to a much more stable ammonium (NH4+) radical. Using this methodology, means that the farmer does not need to supply nitrogen to his fields, but can use the farm’s own home-grown manure. It is a step in the right direction towards a “real” cycle.

During the spring of 2016, the project discovered a safe manure spreading solution from lagoon to land. It has elected to use a two-stage solution where the whole is built around a framework (pumping liquid manure through soft hoses to the edge of the field), and then a system to disperse it over the field. Different dispersion techniques will be tested, adapted to the farm’s varied landscape.

To spread the manure on the fields a dribble bar is used. The great advantage of the method is
that loss of nutrients (primarily nitrogen) is minimized. Photo: BalticSea2020.

From the storage lagoons, the liquid manure is pumped through soft hoses out to the edge of the field. Then, to spread the manure on the fields, a dribble bar (see illustration above) is used. The manure is pumped directly to the tractor through feed hoses connected to a hard trailer hose (see illustration below) which is dragged out onto the field, and then on to the tractor’s application system. The manure is spread onto the field using a number of hoses, all the way up to the roots of the plants. The great advantage of this method is that the loss of nutrients (primarily nitrogen) is minimised. When manure is simply cast out into the field, it is easy for it to end up in the plants’ leaves, which leads to a risk of leaching of the nutrients. When, however, it is laid directly at the roots of the plants, the plants can more easily assimilate the nutrient rather than let it escape into the air and water. Using this method makes it also possible for the farm to deliver the manure around the clock. The hard hose can also be used for irrigation.

The manure is pumped directly to the tractor through feed hoses connected to a hard trailer hose which is
dragged out onto the field, and then on to the tractor’s application system. The hard hose can also be used
for irrigation. Photo: BalticSea2020.

Until the spring of 2017, a number of dispersion experiments will be undertaken to evaluate whether the technology meets the purpose and goals of the project. The project will also be running a scientific monitoring programme in parallel with this, to measure and evaluate the impact of the measures taken. The entire project will run until 2020. Our hope is that its accumulated experiences, which are to be presented sometime later, will contribute to other livestock farms (large and small) finding it possible to run sustainable and economical agriculture. 

Read more about the demonstration project on the pig farm in Przybkowo here.