Mycorrhizal, nutritional and virgin olive oil parameters affected by groundcovers

Abstract

Management of olive groves faces the challenge of reconciling yield, soil degradation and virgin olive oil (VOO) quality. We evaluated the effect of replacing tillage management by vegetal groundcovers (GC) on the relationships between mycorrhizal symbiosis, olive nutritional status, and VOO quality under field rainfed conditions. The experiment was set up in 2014 in an existing Cornicabra olive orchard with a Haplic Gypsisol soil under a Mediterranean semiarid climate. Four treatments were replicated four times and consisted of: (1) annual cover of bitter vetch, (2) permanent Brachypodium distachyon, (3) spontaneous vegetation cover (mainly Brassicaceae species), and (4) tilled soil. The use of bitter vetch GC increased the olive root colonization by 50% compared with the tillage treatment. The effect of tillage on VOO differed from that of GC use. Tillage treatment decreased maturity index and its VOO had lower polyphenol content and less luminosity than that from the GC treatments. Olive root colonization, together with changes in nutrients such as Cu, B and other elements resulting from GC use, seems to play an important role in explaining the variability of VOO quality parameters. Although tillage may lead to higher yield by controlling competition for water and nutrients, the introduction of GC in olive groves led to higher polyphenol contents, enhancing VOO quality and, at the same time, protecting soil from erosion.

Olive Fruit Ripening Degree and Water Content Relationships with Phenolic Acids and Alcohols, Secoiridoids, Flavonoids and Pigments in Fruit and Oil

“…For instance, the ripening index varied between 2.2 and 3.1, which corresponds to different steps of the turning phase (reddish spots on ≤50% of the whole fruit epicarp = 2; reddish spots on ≥50% of the whole fruit epicarp). However, these changes were consistent with those reported by García-González et al [21], who compared various soil management practices (tillage, spontaneous vegetation, Brachypodium, and bitter vetch). In their study, the maturity index of olive fruits varied between 1.9 and 2.9 among treatments.…”

“…Ripening is genetically regulated, but water and soil management practices largely influence the maturation process, as well as other fruit traits (i.e., water content in the pericarp). For example, irrigation induces consistent changes in ripening dynamics, fruit oil, and water content [20], and the use of various types of groundcovers can affect ripening and quality traits of the fruit and oil [21]. Moreover, irrigation can shape the phenol profile of olive fruit, thereby influencing enzyme activities (especially L-Phenylalanine ammonia-lyase) [22][23][24].…”

Microbiome Associated with Olive Cultivation: A Review

“…Land cover management in olive groves is a challenge for productivity, soil degradation, and oil quality. To investigate land cover in olive groves, García-González et al [ 13 ] assembled an experiment, also in Spain (40°4′21″ N, 3°31′11″ W), under field conditions, in an olive grove cv. Cornicabra, in the Mediterranean region, with a semi-arid climate, varying the ground cover treatments.…”

“… Subjects covered in the selected papers, in percentage, addressing the effect of management with different soil microorganisms, and in different edaphic conditions, between brackets. Microbial diversity [ 8 , 10 , 12 , 17 , 26 ], Catabolic diversity [ 10 , 11 , 27 ], Microbial density [ 9 , 15 , 17 , 19 , 22 , 23 , 25 , 28 , 37 ], AMF colonization [ 13 , 23 , 29 , 30 , 31 , 32 , 33 , 34 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 48 , 49 ], Soil enzymes [ 14 , 17 ], N 2 fixing [ 19 , 21 ]. …”

Effects of herbaceous covers and mineral fertilizers on the nutrient stocks and fluxes in a Mediterranean olive grove

“…Nonetheless, the net effect on soil water availability is controversial (Ruíz-Colmenero et al, 2011;Palese et al, 2014). It is, as well, not clear whether herbaceous vegetation also competes with olive trees for nutrients, whether yield reductions are extensible to mature trees (Palese et al, 2014;Soriano et al, 2014), and whether this competition also translates into reductions in olive oil quality or production (García-González et al, 2019). Understanding these knowledge gaps may allow optimization of the potential benefits of herbaceous cover maintenance for olive productivity and sustainability.…”