Preliminary results of experiments with organic amendments developed within the European Soil O-Live project show that olive trees treated with a mixture of biochar and compost applied in an infiltrator increase their oil production per tree by between 7 and 24% compared to trees not treated with this organic amendment. The biochar used in the tests is from Carboliva, a company collaborating in the Soil O-Live project. The research that yielded these results was carried out on three different farms, located in Baena (Córdoba), Torreperogil (Jaén) and Chiclana del Segura (Jaén). In one no treatment was applied, in another only compost, in the third compost and biochar were spread around the olive tree, and in the fourth the same mixture was used but inside an infiltrator. One year later, it is evident that this last tree has on average between 0.4 and 1.7 kilos of oil more than the olive tree to which nothing was applied, which represents the aforementioned increase of between 7 and 24%. The rainfed olive groves achieved the best results in these experiments in terms of yield. It is also evident that the soil has improved in terms of organic matter, respiration and water retention especially in the olive tree that had compost and biochar spread.
These conclusions were presented at a meeting held between the coordinator of Soil O-Live and professor of Ecology at the UJA, Antonio Manzaneda; the project researchers Víctor Valenzuela and Mar Isabel Reyes, and the heads of Carboliva, Álvaro and Beatriz Espuny.
Manzaneda explained that these experiments with such promising results will continue on the above-mentioned farms and will also be extended to other experimental plots in Italy, Greece and Portugal, which are also participating in the project. ‘We are satisfied with these first results of remediation experiments, as they show that organic amendments improve soil quality and have the great potential to increase olive production in olive groves in some agronomic contexts,’ said Manzaneda.
Álvaro Espuny, CEO of Carboliva, emphasised that this experiment shows how positive biochar is for olive trees and how it is a totally sustainable solution. ‘At Carboliva we produce our biochar with olive biomass (bone and pulp) and this returns to the tree, providing it with nutrition that makes it more profitable,’ said the Carboliva manager, who also mentioned that the benefits of biochar last for dozens of years.
Soil O-Live and Carboliva will continue to collaborate in the second part of this project led by the University of Jaén, which after analysing the soil of the Mediterranean olive grove, now focuses on the implementation of remediation and rehabilitation solutions.