Veronica Giorgi

Orchard intensification has transformed fruit production through the combined adoption of higher planting densities, dwarfing rootstocks, localized irrigation/fertigation, and increasingly mechanized orchard management. While aboveground outcomes are well documented, belowground responses remain fragmented across species, orchard contexts, and measurement approaches. This systematic review synthesizes field-based evidence on how orchard intensification and its main operational drivers are associated with root system architecture (RSA) and root plasticity in fruit trees. Following systematic searching and study selection, we performed a narrative synthesis because heterogeneity in species, orchard age, intensification metrics, root assessment methods, and reported traits precluded robust quantitative meta-analysis. The reviewed evidence was more frequently structured around co-occurring drivers—particularly irrigation geometry, rootstock vigor, and soil physical constraints—than around planting density manipulations alone. Root distributions were often reported as predominantly shallow and spatially concentrated within managed zones, especially along tree rows under localized irrigation, with shifts in vertical and lateral allocation that appeared context-dependent. These responses varied with species, genotype, and pedoclimatic conditions, suggesting that intensification does not impose a single deterministic RSA outcome, but rather constrains the potential root zone volume, defined here as the soil volume theoretically available for root growth, within which root distribution may be plastically modulated. Overall, we propose an interpretative framework that may help organize the available evidence by distinguishing (i) the structural definition of an effective rooting domain under intensive management and (ii) plastic modulation of root distribution within that domain. The review also highlights a major evidence gap: the scarcity of factorial field experiments that isolate planting density from irrigation design, genotype, and soil physical constraints.

Orchard intensification has transformed fruit production through the combined adoption of higher planting densities, dwarfing rootstocks, localized irrigation/fertigation, and increasingly mechanized orchard management. While aboveground outcomes are well documented, belowground responses remain fragmented across species, orchard contexts, and measurement approaches. This systematic review synthesizes field-based evidence on how orchard intensification and its main operational drivers are associated with root system architecture (RSA) and root plasticity in fruit trees. Following systematic searching and study selection, we performed a narrative synthesis because heterogeneity in species, orchard age, intensification metrics, root assessment methods, and reported traits precluded robust quantitative meta-analysis. The reviewed evidence was more frequently structured around co-occurring drivers—particularly irrigation geometry, rootstock vigour, and soil physical constraints—than around planting density manipulations alone. Root distributions were often reported as predominantly shallow and spatially concentrated within managed zones, especially along tree rows under localized irrigation, with shifts in vertical and lateral allocation that appeared context-dependent. These responses varied with species, genotype, and pedoclimatic conditions, suggesting that intensification does not impose a single deterministic RSA outcome, but rather constrains the potential root zone volume, defined here as the soil volume theoretically available for root growth, within which root distribution may be plastically modulated. Overall, we propose an interpretative framework that may help organize the available evidence by distinguishing (i) the structural definition of an effective rooting domain under intensive management and (ii) plastic modulation of root distribution within that domain. The review also highlights a major evidence gap: the scarcity of factorial field experiments that isolate planting density from irrigation design, genotype, and soil physical constraints.

Understanding the spatial relationship between crop roots and soil biological functioning is essential for improving orchard management. This study investigated the spatial distribution of pear roots and selected soil biological indicators in five intensive ‘Abbé Fétel’ pear orchards in Emilia-Romagna, Italy, representing eight orchard–rootstock combinations. Soil cores were collected from along-row and inter-row positions at two depths (0–20 and 20–40 cm). Root length density (RLD), soil organic matter (SOM), microbial biomass carbon (MBC), soil basal respiration (SBR), and the activities of alkaline phosphatase (ALP), β-glucosidase (BGLU), and N-acetyl-β-D-glucosaminidase (NAG) were determined. Linear mixed-effects models showed that RLD was significantly higher along the tree row and in the upper soil layer. At 0–20 cm, mean RLD was approximately twofold higher along-row than in the inter-row (0.324 vs. 0.133 cm g⁻¹), indicating that pear roots were concentrated within the shallow along-row soil. Soil depth was the main factor influencing all biological indicators. SOM was higher along-row, whereas MBC varied mainly with depth. In contrast, BGLU and NAG activities were higher in the grass-covered inter-row despite lower pear-root density, while SBR showed the highest values in the shallow along-row soil. These findings demonstrate that soil biological indicators do not necessarily mirror crop-root distribution. Instead, belowground functioning in intensive pear orchards reflects the combined influence of crop roots and inter-row vegetation, highlighting the ecological importance of both orchard compartments when assessing soil functioning.

Understanding the spatial relationship between crop roots and soil biological functioning is essential for improving orchard management. This study investigated the spatial distribution of pear roots and selected soil biological indicators in five intensive ‘Abbé Fétel’ pear orchards in Emilia-Romagna, Italy, representing eight orchard–rootstock combinations. Soil cores were collected from along-row and inter-row positions at two depths (0–20 and 20–40 cm). Root length density (RLD), soil organic matter (SOM), microbial biomass carbon (MBC), soil basal respiration (SBR), and the activities of alkaline phosphatase (ALP), β-glucosidase (BGLU), and N-acetyl-β-D-glucosaminidase (NAG) were determined. Linear mixed-effects models showed that RLD was significantly higher along the tree row and in the upper soil layer, indicating that pear roots were concentrated within the shallow along-row soil. Soil depth was the main factor influencing all biological indicators. SOM was higher along-row, whereas MBC varied mainly with depth. In contrast, BGLU and NAG activities were higher in the grass-covered inter-row despite lower pear-root density, while SBR showed the highest values in the shallow along-row soil. These findings demonstrate that soil biological indicators do not necessarily mirror crop-root distribution. Instead, belowground functioning in intensive pear orchards reflects the combined influence of crop roots and inter-row vegetation, highlighting the ecological importance of both orchard compartments when assessing soil functioning.

Sustainable weed management is a key challenge in fruit and olive orchards. Conventional practices, such as intensive weed control and monoculture, can degrade soil quality and reduce biodiversity, threatening long-term productivity. Living mulch, defined as an herbaceous soil coverage, grown alongside the main crop, represents a promising agroecological strategy for enhancing ecosystem services. However, current knowledge on living mulch in orchards remains fragmented, with studies often focusing on single ecosystem functions and providing context-dependent and sometimes contrasting results. This limits the ability to identify consistent patterns and to support practical decision-making. To address this gap, this systematic review synthesizes and integrates the available evidence on the effects of living mulch on orchard agroecosystems, focusing on weed suppression, soil fertility, biodiversity, soil physical and chemical properties, pest control, agronomic performance, and tree root system dynamics. Findings indicate that living mulch contributes to undesired species suppression (82 records), increases biodiversity and soil fertility (109 records), enhances soil microbial activity and nutrient cycling (120 records), improves soil structure and water retention (66 records), and supports beneficial insect populations for natural pest control (49 records). However, living mulch may also introduce challenges such as resource competition with fruit trees and potentially provide habitats for rodents. The magnitude of these effects varies depending on species selection, pedoclimatic conditions, and management practices. A satisfactory outcome of introducing living mulch in an orchard depends on selecting the appropriate living mulch species and management practices, as well as on shifting farmers’ perspectives to emphasize the long-term ecosystem services of living mulches rather than focusing solely on short-term crop yield. A participatory approach involving farmers is essential for optimizing living mulch integration into orchard systems. Long-term studies are needed to assess the resilience and productivity of living mulch-based management strategies over time.

The olive ( Olea europaea L.) germplasm of the Mediterranean basin is very rich and is characterized by a huge number of cultivars, more than 1200 already identified. The aim of our study was to evaluate these genotypes to be considered for further breeding programs or eventually for direct cultivation in super‐high‐density (SHD) planting systems. Some spontaneous, wild, and locally neglected genotypes from Italy (Sardinia), not previously and fully described, were collected and in the Autumn of 2015, 14 genotypes were planted in Apulia (Foggia province), the main Italian region for olive growing. In 2017, 2018, and 2019, several architectural parameters of the canopy were measured, and the fruits were characterized. Results identified two possible genotypes suitable for SHD cultivation or to be included in future breeding programs. These selected genotypes showed good architectural characteristics and high average fertility index. This study showed that spontaneous, wild, and local relict genotypes can represent a huge germplasm resource to identify interesting genotypes for cultivation and parentals for breeding programs.

Global warming, with rising average temperatures and increasingly frequent extreme heat events, poses a major threat to fruit production systems and food security. Understanding how fruit trees respond to soil thermal stress is therefore critical for developing climate-resilient orchards. In this study, we investigated the physiological and growth responses of potted pear (Pyrus communis) and quince (Cydonia oblonga) plants to root-zone heating. Plants were exposed to different substrate heating regimes, and gas exchange, water status, chlorophyll content, shoot growth, and biomass allocation were assessed. Short-term extreme heating (50 °C for 36 h) caused immediate reductions in gas exchange, severe root and shoot damage, and rapid plant mortality in both species. By contrast, prolonged heating at 40/35 °C induced significant declines in gas exchange, shoot growth, and root biomass, with species-specific differences. Pear exhibited greater sensitivity than quince, showing lower shoot growth, root dry weight, and gas exchange. These findings highlight the vulnerability of pear trees to high root-zone temperatures and the limited contrast between the tested rootstocks. Accordingly, there is a clear need for targeted soil management practices that promote root growth and soil exploration to enhance orchard resilience under future climate scenarios.

Global warming, with rising average temperatures and increasingly frequent extreme heat events, poses a major threat to fruit production systems and food security. Understanding how fruit trees respond to soil thermal stress is therefore critical for developing climate-resilient orchards. In this study, we investigated the physiological and growth responses of potted pear (Pyrus communis) and quince (Cydonia oblonga) plants to root-zone heating. Plants were exposed to different substrate heating regimes, and gas exchange, water status, chlorophyll content, shoot growth, and biomass allocation were assessed. Short-term extreme heating (50 °C for 36 h) caused immediate reductions in gas exchange, severe root and shoot damage, and rapid plant mortality in both species. By contrast, prolonged heating at 40/35 °C induced significant declines in gas exchange, shoot growth, and root biomass, with species-specific differences. Pear exhibited greater sensitivity than quince, showing lower shoot growth, root dry weight, and gas exchange. These findings highlight the vulnerability of pear trees to high root-zone temperatures and the limited contrast between the tested rootstocks. Accordingly, there is a clear need for targeted soil management practices that promote root growth and soil exploration to enhance orchard resilience under future climate scenarios.

Proximal plant-based monitoring provides high-resolution data about trees, leading to more precise orchard management and in-depth knowledge about tree physiology. The present work focuses on continuous real-time monitoring of olive cv. ‘Ascolana tenera’ over hourly intervals during the third stage of fruit growth (mesocarp cell expansion) under mild water stress conditions (ψStem above −2 MPa). This is achieved by mounting dendrometers on the root, trunk, branch, and fruit to assess and model the behavior of each organ. The diameter variation in each organ over different time intervals (daily, two-weeks, and throughout the entire experiment), as well as their hysteretic patterns relative to each other and vapor pressure deficit, are demonstrated. The results show different correlations between various organs, ranging from very weak to strongly positive. However, the trend of fruit versus root consistently shows a strong positive relationship throughout the entire experiment (R² = 0.83) and a good one across various two-week intervals (R² ranging from 0.54 to 0.93). Additionally, different time lags in dehydration and rehydration between organs were observed, suggesting that the branch is the most reactive organ, regulating dehydration and rehydration in the tree. Regarding the hysteretic pattern, different rotational patterns and characteristics (shape) were observed among the organs and in relation to vapor pressure deficit. This research provides valuable insight into flow dynamics within a tree, models plant water relations and time lags in terms of water storage and transport, and could be implemented for precise olive tree water status detection.

Proximal plant-based monitoring provides high-resolution data about trees, leading to more precise orchard management and in-depth knowledge about the tree physiology. The present work focuses on continuous real-time monitoring of olive cv. 'Ascolana Tenera' on an hourly time span during the third stage of fruit growth (mesocarp cell expansion) under mild water stress conditions (ψStem above -2 MPa). This is achieved by mounting dendrometers on the root, trunk, branch, and fruit to assess and model the behavior of each organ. The diameter variation of each organ at various time intervals (daily, two-weeks, and entire experiment), as well as their hysteretic patterns relative to each other and vapor pressure deficit, has been demonstrated. The results show different correlations between various organs, ranging from very weak to strongly positive. However, the trend of fruit versus root consistently shows a strong positive relationship throughout the entire experiment (R² = 0.83) and good across various two-week intervals (R² ranging from 0.54 to 0.93). Additionally, different time lags in dehydration and rehydration between organs were observed, suggesting that the branch is the most reactive organ, regulating dehydration and rehydration in the tree. Regarding the hysteretic pattern, different rotational patterns and characteristics (shape) were observed among the organs and in relation to vapor pressure deficit. This research provides valuable insight into the flow dynamics within a tree, models plant water relations and time lags in terms of water storage and transport and could be implemented for precise olive tree water status detection.