Managing the composting of different organic waste offers new possibilities. For this reason, a team of specialists from INTA – made up of researchers from Hilario Ascasubi, Balcarce and Bariloche – is working on the development of a new biological fertilization strategy: compost pellets. It is an organo-mineral fertilizer made from agricultural residues. Preliminary results determined that, after its application, wheat yielded 19% more, compared to sources of inorganic nitrogen (N) and phosphorus (P).
With the aim of evaluating alternatives that promote the use of by-products, Luciano Orden –of INTA Hilario Ascasubi, Buenos Aires– together with Walter Carciochi –of the Integrated Unit INTA – Faculty of Agrarian Sciences of Balcarce, Buenos Aires– and Javier Ferrari – from INTA Bariloche, Río Negro– designed, formulated the pellets and evaluated them in the field, in a wheat crop.
In the long term, the premise is to be able to incorporate compost into extensive crops and, in some way, return part of what is extracted to the soil. “Agricultural and agro-industrial waste can be used as raw material for the generation of products with added value, among which the generation of bioenergy, animal feed or biofertilizers stands out,” said Orden, who is a specialist in organic waste management.
To move forward, the team of researchers applied the concept of ‘circular economy of agro-industrial waste’, whose central axis points to the reuse of organic waste so that the extracted nutrients are recovered and reintroduced into the production cycle.
With this premise, in the 2020 campaign, they advanced in the evaluation of pelleted organo-mineral fertilizer, as a source of nitrogen (N) and phosphorus (P), in wheat. At the same time, they compared it with plots that had received conventional fertilization (inorganic N and P). The test was carried out in the experimental field of the Integrated Unit INTA – FCA Balcarce, on a Typical Argiudol, Mar del Plata series. The phosphate fertilization, both inorganic and organo-mineral, was carried out at sowing, while nitrogen (both sources) was applied to the surface boleo at the time of two tillers.
Among the most outstanding results, Carciochi stressed that “with the use of organo-mineral fertilizers with P and N, the yield of wheat increased by 19%, with respect to inorganic sources”, and added: “The number of grains per unit of surface followed a trend similar to that observed for yield, while both fertilization treatments increased the concentration of protein and gluten in grain, in a similar magnitude ”.
“Although these results are preliminary, they are very encouraging and we will continue to make evaluations in the next campaigns,” said Carciochi.
everything transforms
“For the assembly of the pellets it is very important to have a stable and mature compost”, stated Orden who explained that, in this case, they were formulated from the composting of livestock waste from cattle manure, poultry, but it is also It is possible to use compost from household food scraps. The organic matter was conditioned through a composting system, which was carried out in the field, with mechanized removal (in English, windrow composting).
During the compost pelletization process it is possible to lower the humidity and increase the apparent density of the product, two conditions that facilitate its distribution using almost any machine. During the treatment, the compost reaches an initial humidity close to 60%. Then, it is dried until it reaches between 12 and 15% humidity, an optimal value for pelletizing, and then it is allowed to air until it reaches between 3 and 5%.
“The compost pellet has some advantages over the sifted compost that comes directly from the field”, highlighted Ferrari who explained: “It is applied with conventional fertilization machines, much more organic material is incorporated per square meter, because it has less humidity , it is distributed better, it can be stored and it is even more efficient to transport in terms of logistics ”.
At the Inta Bariloche, Ferrari made progress in the development of an experimental machine that makes it possible to densify the compost and compress it to a smaller and more compact format, ideal for distribution with any fertilizer / seeder. Likewise, the experimental machine served as the basis from which the format and composition could be extrapolated for the industrial-scale production of pellets.
–
