This guide was developed in the framework of the LIFE ENV/GR/951 project, entitled “Sustainable strategies for the improvement of seriously degraded agricultural areas: the example of Pistachia vera L.” (AgroStrat) and aims to provide useful information and instructions to pistachio producers and farmers from the Mediterranean region regarding composting in field of the solid wastes generating after dehulling of pistachio nuts, as well as to present the composting method developed during the project.
One of the main objectives of the AgroStrat project was to recycle the solid waste produced from pistachio nuts processing. Therefore, a composting technique was developed using pistachio wastes, manure, straw and the natural zeolite, clinoptilolite. Clinoptilolite was added to the compostable mixture in order to adsorb the excess salts concentration and at the same time to contribute to the overall quality of the final product. This was the first time that a natural zeolite was used as feedstock component to this composting process, aiming to facilitate the production of an improved compost, which apart of the known properties will also act as “slow-release” fertilizer, due to the well-known properties of clinoptilolite to adsorb and keep essential nutrients in its framework and release them upon plant demand.
The potential harmful organic substances of pistachio wastes, and mainly polyphenols, were degraded during the composting process, allowing the safe use of the obtained compost in agricultural fields.
Therefore, composting could be an interesting alternative in recycling this type of agricultural waste produced in Mediterranean areas, resulting in an organic fertilizer suitable to be applied at pistachio orchards and not only, saving
fertilization costs and improving the poor and erosion-endangered Mediterranean soils.