Effects of the Soil Incorporation of Increasing Amounts of Non-Fermented Wet Pomace on the Oil Yield and Acid Profile of Sunflower (Helianthus annuus L.) Seeds

Abstract The agricultural use of olive processing waste is a strategic resource in the integrated management of the agricultural system as it satisfies the two objectives of evacuating the olive-processing residue and using it beneficially for agricultural purposes. For such aims, a research was conducted in Bari (South of Italy) to study the effects of the incorporation into the soil of increasing amounts of non-fermented wet pomace (WP) (0, 17.5, 35, 70, 105, 140, 175, 210 Mg ha-1) on the oil yield and acid profile of sunflower seeds. The results obtained point out that the seed yield was negatively affected by the application of WP starting from 70 Mg ha-1; an opposite trend was observed for the seed oil yield. The incorporation of WP has also affected the oil fatty acids’ composition. Oleic and linoleic acids, the principal fatty acids (beyond 90% of total fatty acids), showed significant variations: from the control treatment to the one receiving the maximum application of waste, oleic acid decreased (-5.4%), linoleic acid increased (+ 6.6%), and the saturated fatty acids fraction decreased (-7.6%).