Nowadays, the increased concentration of livestock farms has led, in certain areas, to the generation of more slurry than local agricultural lands and crops can assimilate.
Farmers are obliged to transport the slurry further and further afield to find cropland where it can be applied.
Transportation costs in these situations are higher than the actual value of fertiliser, making it increasingly difficult to manage.
The solution to this problem can be addressed in two different ways.
First, by extraction and concentration of the nutrients contained in the slurry, so it can be transported more easily and economically; or second, adaptation of the slurry by incorporating different additives to make it suitable and profitable for application on croplands, where its potential use is limited due to its lower fertiliser value.
This second strategy is described as on-farm TMF production. Potato was selected as a target crop because it is a typical crop of the area with large nutrient extractions from the soil. For the formulation and production of the specific TMF, the following aspects were taken into consideration:
1. The nutrients needing to be added to meet the demands of the potato crop.
2. Nitrogen stabilisation techniques allowing for controlled nutrient release during the cultivation season since some crops are not compatible with dressing fertilisation.
3. Pig slurry contains large amounts of Zn, Cu, and antibiotics. Application of a large amount of slurry can cause a situation of toxicity stress to the plant. Incorporation of chemically complex humic acids should reduce the bioavailability of these substances.
4. Stabilised biostimulants could increase nutrient use efficiency.
A farmer’s traditional mineral fertilisation plan was compared with a fertilisation plan incorporating the TMF in substitution of NPK fertiliser application.
Since the assay is still underway, final productivity results will be available in the coming months.
Also, different types of monitoring are being carried out to assess the impact of the TMF fertilisation plan on soil and crop performance.
For example, inorganic nitrogen is being monitored in soil and leaf to assess the stability and uptake efficiency of this nutrient. Metagenomic trials are also being carried out to assess the impact of TMF on the soil microbiome.
Over the next months more data will be taken as production and fruit quality to evaluate the efficiency of the new TMF.