The environmental impact of olive cultivation and olive oil production is important as oil extraction requires a considerable amount of water and generates huge quantities of oil mill wastes. Moreover, such huge quantities are concentrated in a limited period of time, corresponding to two-three months of olive harvesting. In many olive-growing countries, as for example in Italy, the agronomic use of olive mill wastes, i.e. waste waters (OMWW) and pomace, by directly spreading in the field is a widespread method of legal disposal. Such use has taken great interest not only because it is a relatively inexpensive and easily feasible, but also because it allows to give organic matter to the soil, whose progressive depletion in soils subjected to intensive farming is a source of great concern, due to worsening of physical, chemical and biological soil properties, leading to degenerative phenomena, of which erosion and loss of fertility are the most obvious and worrying aspects. However, the spreading in the field of OMWW and pomace should be implemented with rationality since the little stabilized organic materials may inhibit or reduce the development of crops, due to I) the presence of tannins, fatty acids and phenols, II) the competition for the nitrogen among the microorganisms of the soil and the roots due to a high C/N ratio, and III) anoxia of the roots caused by the microorganism consumption of oxygen. In particular, the high concentration of polymeric phenols could have a bacteriostatic effect on micro-organisms and some phytotoxic effect on cultivations. Also the high content of salts and the slightly acidic reaction suggest the need to manage this waste carefully. On the other hand, large quantities of phosphorous and potassium and organic matter can give a significant contribution to the fertilization of cultivated soil. In this chapter, on the basis of the specific literature, the benefits, the risks and the correct use of the oil mill wastes as soil amendment are described.
Reuse of olive mill waste as soil amendment
Regni, L.
;Gigliotti, G .;Nasini, L .;Proietti, P.
2017
Abstract
The environmental impact of olive cultivation and olive oil production is important as oil extraction requires a considerable amount of water and generates huge quantities of oil mill wastes. Moreover, such huge quantities are concentrated in a limited period of time, corresponding to two-three months of olive harvesting. In many olive-growing countries, as for example in Italy, the agronomic use of olive mill wastes, i.e. waste waters (OMWW) and pomace, by directly spreading in the field is a widespread method of legal disposal. Such use has taken great interest not only because it is a relatively inexpensive and easily feasible, but also because it allows to give organic matter to the soil, whose progressive depletion in soils subjected to intensive farming is a source of great concern, due to worsening of physical, chemical and biological soil properties, leading to degenerative phenomena, of which erosion and loss of fertility are the most obvious and worrying aspects. However, the spreading in the field of OMWW and pomace should be implemented with rationality since the little stabilized organic materials may inhibit or reduce the development of crops, due to I) the presence of tannins, fatty acids and phenols, II) the competition for the nitrogen among the microorganisms of the soil and the roots due to a high C/N ratio, and III) anoxia of the roots caused by the microorganism consumption of oxygen. In particular, the high concentration of polymeric phenols could have a bacteriostatic effect on micro-organisms and some phytotoxic effect on cultivations. Also the high content of salts and the slightly acidic reaction suggest the need to manage this waste carefully. On the other hand, large quantities of phosphorous and potassium and organic matter can give a significant contribution to the fertilization of cultivated soil. In this chapter, on the basis of the specific literature, the benefits, the risks and the correct use of the oil mill wastes as soil amendment are described.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
