Article

Sustainability of olive growing in the Mediterranean area under future climate scenarios: Exploring the effects of intensification and deficit irrigation

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Abstract

Olive orchards represent a key agricultural system with high economic and environmental prominence. Expected future climate tendencies over the Mediterranean could threaten the sustainability of such strategic tree crop. This study evaluates the productive and environmental performance of olive orchards under different climate change scenarios and management strategies across the main olive-farming regions over southern Europe using the process-based model OliveCan. Simulations were performed for low density LD (100 trees ha⁻¹), high density HD (400 trees ha⁻¹) and super high density SHD (1650 trees ha⁻¹) olive orchards over baseline period (1980-2010) and future scenarios (2041–2070 and 2071–2100 for RCP4.5 and RCP8.5). Results showed that the future increase in CO2 concentration may compensate the negative effects of higher evaporative demand and diminished water supply resulting in an enhancement of water use efficiency and carbon capture potential in olive orchards. Irrigation requirement for the maximum productivity are expected to increase by 5−27%. Moreover, rainfed low density orchards will be the most vulnerable to expected climate changes, in particular in the driest areas. In fact, a decrease in yield up to 28 % with an increase in its interannual variability of 20 % is expected over the Iberian Peninsula while yield increased up to 26 % over the centre of the Mediterranean. Deficit irrigation and intensification will improve olive orchard productivity and carbon sequestration capacity. Besides, the decrease in winter chilling is not expected to be enough to produce significant flowering anomalies or failures over the study area. Even though findings of this research showed that olive orchards may benefit from future conditions, assessment of management alternatives at local scale will be a must for a better adaptability of olive orchards.

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... This vulnerability has been increasing for decades, driven by two factors: (1) the migration of the rural population to urban areas, resulting in a lack of labor and generational renewal, leading to the abandonment of marginal, remote, and least productive rural areas [17]; and (2) the entry into force of the Common Agricultural Policy (CAP), a policy which was first started in 1957, and which although it currently includes resilient agriculture and rural development measures, for many past decades focused on the productive dimension of rural areas, disregarding their environmental one, thus partly driving the collapse of traditional olive farms [18,19]. In order to alleviate the economic vulnerability of Mediterranean olive groves, crops have either been abandoned, due to their low financial profitability, or intensified, to increase their productivity by increasing plant densities, technification, and application of energy, irrigation, and agrochemical inputs (i.e., herbicides, pesticides, and fertilizers) [18,20,21]. While rural land abandonment leads to an increase in land scrubbing and an erosion of social and territorial cohesion [22], a rapid and unsustainable trend towards intensification may likely lead to an increase in soil erosion, landscape homogenization, and diffuse pollution, all of which negatively impact the multifunctionality and sustainability of olive groves and associated landscapes [20,21,23]. ...
... In order to alleviate the economic vulnerability of Mediterranean olive groves, crops have either been abandoned, due to their low financial profitability, or intensified, to increase their productivity by increasing plant densities, technification, and application of energy, irrigation, and agrochemical inputs (i.e., herbicides, pesticides, and fertilizers) [18,20,21]. While rural land abandonment leads to an increase in land scrubbing and an erosion of social and territorial cohesion [22], a rapid and unsustainable trend towards intensification may likely lead to an increase in soil erosion, landscape homogenization, and diffuse pollution, all of which negatively impact the multifunctionality and sustainability of olive groves and associated landscapes [20,21,23]. ...
... In contrast, the organic management systems allow the presence of living or inert plant cover and organic fertilizers, which results in greater soil fertility rates and a reduction in diffuse pollution [26,27]. These management methods are typically rainfed, but they also fit with deficit irrigation systems (i.e., water addition of up to 1500 m 3 ha −1 year −1 focusing on periods with hydric stress) [20,25]. This is particularly important in Alentejo, a region with a Mediterranean climate where, paradoxically, water resources have not lately been considered as a constraint to agricultural development. ...
Article
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Olive groves are Mediterranean socioecological systems. In Portugal (350,000 hectares of olive groves), a transition is ongoing towards intensification. Such effects may arise from the incremental use of agrochemical fertilizers. The Alentejo region, Portugal, was stratified according to the olive management systems (i.e., extensive groves managed conventionally, integrated or organically, and intensive and highly intensive farms) and erosive states. Agronomic (i.e., fertilizers) and biological (i.e., herbaceous and lepidopteran richness and biodiversity) variables were quantified in 80 plots so we could know how managements affect biodiversity. Intensive and highly intensive farms showed the highest erosion (up to 48 t ha−1 year−1) and the highest concentration of nitrates (11–16 ppm), phosphates (8–15 ppm), and potassium (169–183 mg kg−1), aligned with its lower flora (null) and fauna (0.50–1.75 species). Conventional extensive farms attained an intermediate position, and integrated and organic managements showed the lowest erosion (up to 20 t ha−1 year−1), and the lowest concentration of nitrates (5–6 ppm), phosphates (2–4 ppm), and potassium (92–125 mg kg−1) aligned with its higher flora (14–27 species) and fauna (up to 8 species). Studies aimed at characterizing the multifunctionality of olive groves are essential in Portugal, also considering how soil practices can minimize externalities driven by rapid changes in crop systems.
... Currently, predictions on how carbon and water economy in olive orchards will be affected by multiple global change variables are based mostly on models used to simulate different climate scenarios in the Mediterranean Basin rather than experimental field studies (e.g., Tanasijevic et al., 2014;Lorite et al., 2018;Fraga et al., 2020;Mairech et al., 2021). Such models have often indicated that the potentially negative effects of higher temperatures and less rainfall on photosynthesis and yield may be ameliorated by a beneficial response to the rising global CO 2 concentration and by increasing irrigation amounts. ...
... Such models have often indicated that the potentially negative effects of higher temperatures and less rainfall on photosynthesis and yield may be ameliorated by a beneficial response to the rising global CO 2 concentration and by increasing irrigation amounts. Nevertheless, a need to develop more sophisticated temperature sub-models has been identified (Mairech et al., 2021). Thus far, physiological leaf and whole plant responses to prolonged temperature increases have received little attention in olive trees. ...
... The combined responses to water deficit and warming may be most felt in small, traditional orchards that are rain fed and do not have the possibility of obtaining supplemental irrigation. Increasing atmospheric CO 2 could ameliorate such effects through stomatal closure (Mairech et al., 2021), and experimental studies combining CO 2 with other climate factors are urgently needed for olive trees. ...
Article
Changes in rainfall patterns and increases in ambient air temperature (i.e., warming) are expected with climate change. Yet, little information is available on how plant water status will respond to the combination of water deficit and increased air temperature in fruit tree species. The objective of this study was to evaluate the individual responses of deficit irrigation and warming and their combination on plant water status during the late winter and spring in young olive trees. Two temperature and two irrigation levels were applied in open top chambers during the late winter and spring of 2018 and 2019 to two- or three-year-old, potted trees (cv. Arbequina in 2018; Coratina in 2019). The temperature levels were a near-ambient control and a warming treatment that was 4 °C above the control, while the two irrigation levels were 100% and 50% of irrigation needs. Midday stem water potential (Ψs), stomatal conductance, net leaf photosynthesis, transpiration, and leaf temperature were measured periodically, and the difference between leaf and air temperature (ΔT) was calculated. The Ψs generally decreased due to irrigation deficit and warming when applied individually. When both treatments were combined, an additive response was observed. In contrast, stomatal conductance and net photosynthesis were consistently decreased by deficit irrigation, but were less affected by warming. Irrigation deficit did not affect leaf temperature under our experimental conditions. As was expected, warming most often increased leaf temperature, but it also significantly decreased ΔT early in the season when leaf transpiration appeared to be greater due to warming. The results indicate that modifications in water management with global warming will likely be required given the mostly negative individual or additive effects of irrigation deficit and air temperature on Ψs and other variables.
... According to the Intergovernmental Panel on Climate Change (IPCC), climate change scenarios are predicting especially abrupt effects in the Mediterranean region, including increase of hot extremes and agricultural drought 4 , where agricultural management practices will need to define strategies focused on climate resilience to mitigate negative socioeconomic consequences 5,6 . Effects on olive orchards will be complex and hard to predict 7,8 . Current trends indicate that higher evapotranspiration and lower precipitation might lead to a decrease in the area suitable for olive crops and olive oil production in some zones of the Mediterranean basin 5,9,10 , while production might increase in others 11,12 . ...
... Current trends indicate that higher evapotranspiration and lower precipitation might lead to a decrease in the area suitable for olive crops and olive oil production in some zones of the Mediterranean basin 5,9,10 , while production might increase in others 11,12 . Olive groves located in southern Iberia and Italy will be the most affected by the negative impacts of climate change 7,12 . According to RCP4.5 and RCP8.5 scenarios, mean temperature during the growing season of olive trees is expected to increase up to 3ºC 13 and annual precipitation in expected to decrease around 80-90 mm 14 . ...
... These changes will increase the growing season length, while the increase in the frequency and intensity of droughts 15 is expected to cause a yield decrease up to 45% 13 . New management practices will be needed to adapt olive groves in southern Spain to the new climatic conditions 2,7,16 , in order to mitigate negative social and economic impacts. ...
... Owing to the inherent limitations of traditional drip infiltration evaluation tests [24][25][26][27], it is necessary to analyze the complex effects of moisture infiltration on the irrigation scheduling and field capacity of multi-layered agronomic soils [28,29]. Moreover, regarding infiltration quality predictions, studies [30][31][32][33][34][35] have reported the latest investigative results in terms of predictive optimization for estimating on-the-spot infiltration quality. It is understandable that SDIQ predictions cover the majority of soil irrigation performance results and present original suggestions for enhancing the drip infiltration productivity. ...
... Above, N fx = N fy = P, σ(N fx , N fx ) = σ(N fy , N fy ) = σ 2 2 , σ(N fx , N fy ) = σ(N fy , N fx ) = 0. To simplify the predictive analysis, a fast Fourier transformation (mathematical) is applied to determine the spectrum of the probabilistic density of the drip infiltration depth, which can be updated with the probabilistic frequency of the controlled parameter sampling. This yields the following mathematical expression of infiltration quality [32,33]: ...
Article
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Considering the high quality requirements related to agricultural production, the intelligent prediction of sprinkler drip infiltration quality (SDIQ) of the moisture space distribution in soil fields is an important issue in precision irrigation. The objective of this research is to adaptively predict an optimal data set of SDIQ indices using a robust prediction algorithm called the regulated sparse autoencoder–niche particle swarm optimization (RSAE-NPSO) system, so that the SDIQ indices of various irrigated layers of loam, sandy, chernozem, saline–alkali, and clay soils can be predicted and analyzed. This prediction procedure involves the following steps. First, the drip infiltration effectiveness of the moisture on specific irrigated soil layers is measured. Second, a complete set of SDIQ indices used for assessing the moisture space distribution is introduced. Third, an analytical framework based on the RSAE-NPSO algorithm is established. Fourth, the intelligent prediction of SDIQ indices using RSAE-NPSO computation is achieved. This research indicates that when the irrigation parameters include the sprinkling pressure (Pw) at 224.8 KPa, irrigation duration time (Id) at 2.68 h, flow discharge amount (Fq) at 1682.5 L/h, solar radiation (Sr) at 17.2 MJ/m2, average wind speed (Aw) at 1.18 m/s, average air temperature (At) at 22.8 °C, and average air relative humidity (Ah) at 72.8%, as well as the key variables of the irrigation environment, including the soil bulk density (Sb) at 1.68 g/cm3, soil porosity (Sp) at 68.7%, organic carbon ratio (Oc) at 63.5%, solute transportation coefficient (St) at 4.86 × 10−6, evapotranspiration rate (Ev) at 33.8 mm/h, soil saturated hydraulic conductivity rate (Ss) at 4.82 cm/s, soil salinity concentration (Sc) at 0.46%, saturated water content (Sw) at 0.36%, and wind direction Wd in the north–northwest direction (error tolerance = ±5%, the same as follows), an optimal data set of SDIQ indices can be ensured, as shown by the exponential entropy of the soil infiltration pressure (ESIP) at 566.58, probability of moisture diffusivity (PMD) at 96.258, probabilistic density of infiltration effectiveness (PDIE) at 98.224, modulus of surface radial runoff (MSRR) at 411.25, infiltration gradient vector (IGV) at [422.5,654.12], and normalized infiltration probabilistic coefficient (NIPC) at 95.442. The quality inspection of the SDIQ prediction process shows that a high agreement between the predicted and actual measured SDIQ indices is achieved. RSAE-NPSO has extraordinary predictive capability and enables much better performance than the other prediction methods in terms of accuracy, stability, and efficiency. This novel prediction method can be used to ensure the infiltration uniformity of the moisture space distribution in sprinkler drip irrigation. It facilitates productive SDIQ management for precision soil irrigation and agricultural crop production.
... Studies have shown that amendments based on alperujo can influence the soil enzymatic activity that controls the patterns of organic matter decomposition , increase soil fertility through the slow release of nutrients (Alburquerque et al., 2011), improve soil water-soluble carbon , modify soil chemical properties (Podgornik et al., 2022) or the oil quality (Proietti et al., 2015). In this sense, irrigation management has been proposed as a central piece to maximize the effect of the organic amendments and as a tool to palliate the effect of climate change (Kavvadias 55 and Koubouris, 2019;Mairech et al., 2021;Michalopoulos et al., 2020). However, little attention has been paid to how the agronomic effects of the compost or organic amendments can evolve under different irrigation regimes, essential with high tree densities. ...
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Soil and water efficient management are key factors to ensure olive sustainable production. The use of compost based on olive waste (alperujo) as fertilizer could enhance ecosystem services while the need to transition to a zero waste circular economy is achieved. The present work includes a comparative study of the effect of alperujo compost (AC) vs inorganic fertilization under different management systems: an intensive traditional adult olive grove under rainfed conditions and a young hedgerow olive system, in which a factorial test of tree irrigation regimes (full, deficit and no irrigation) is implemented as well. At the hedgerow plots, the addition of AC and soil sampling time greatly impacted soil chemical parameters and to a lesser extent, enzymatic activities whereas irrigation regimes did not exert a mark influence. In the traditional rainfed system, the addition of AC proved to be an efficient tool for carbon sequestration. The first soil sampling revealed a clear stoichiometric relationship between soil organic matter (SOM) and the NPK contents at both systems whereas the correlations were weak and scarce in the second sampling at the hedgerow plots. This fact was related to a decay of the compost effect. Compost in combination with irrigation tended to trigger a certain priming effect on the native SOM with time since the carbon stocks were reduced between 6–38 % from one sampling to the other in the hedgerow system depending on the irrigation intensity. However, the deficit irrigation caused a less intense reduction of the SOM and essential nutrients representing the best alternative to maximize the agronomics effects of the compost under a water-saving strategy. Recurrent application of compost would be necessary to maintain soil quality, especially with high tree densities. The combined management of AC and the deficit irrigation proved to be an efficient tool toward a zero waste circular economy and a water conservation strategy.
... En estas regiones (áridas y semiáridas), la vulnerabilidad al cambio climático, combinada con la sobreexplotación de los recursos hídricos, está poniendo en peligro la seguridad alimentaria y el olivo no es ajeno a esta problemática (Abahous et al., 2021), por lo tanto, los olivares representan un sistema agrícola clave con un gran protagonismo económico y medioambiental (Lombardo et al., 2021;Mairech et al., 2021) y el incremento de la temperatura, en alrededor de 3 °C en condiciones invernales suaves, podría generar valores negativos de margen neto y productividad del agua de riego (Cabezas et al., 2021). ...
Article
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La región de Tacna, Perú, caracterizada por su hiperaridez, se encuentra ubicada en la cabecera del desierto de Atacama, donde la agricultura es uno de los principales sectores económicos y el cambio climático causa grandes impactos, especialmente sobre la sostenibilidad del cultivo de olivo reflejada en la baja producción de aceituna. En este trabajo buscamos identificar la sostenibilidad del cultivo de olivo en la región de Tacna, basada en un enfoque climatológico, correlacionando la producción del cultivo con el fenómeno El Niño-Oscilación del Sur (ENOS). La sostenibilidad del cultivo está directamente relacionada con el clima, siendo la temperatura el factor principal, con amplitud de tolerancia térmica de -7 °C a 40 °C, amplitud óptima entre 15 °C y 25 °C y amplitud en la región de estudio entre 7 °C y 32 °C, lo que consideramos adecuado según los rangos establecidos, donde se obtienen rendimientos relativamente altos respecto a otras regiones del mundo. Por su lado, el fenómeno ENOS, identificado en los años de baja producción: 1980, 1983, 1992, 1998, 2009, 2015 y 2016, reportó volúmenes de producción que se reducen drásticamente. Un caso muy marcado ocurrió en el año 1998, en el cual la producción nacional (Perú) y regional (Tacna) se redujeron a 1,5 y 1,0 miles de toneladas (t), respectivamente, mientras que los valores máximos corresponden a 190,0 y 148,0 miles de t, respetivamente, para el periodo 1979-2020. Hacia el año 2025, convergen las producciones local y nacional, representando que la local sería el 100 % de la nacional.
... Each stage (BBCH 11,37,53,60,65,69) is explained in latitude locations than the higher latitudes in western Argentina with a range of about 800 to 1300 chilling units (Table 2). These chilling units are sufficient for the chilling requirements of these particular cultivars, but are lower than the historical values (1550-2050) for the traditional growing region of Andalucía (Mairech et al., 2021). This likely occurs because the minimum winter temperatures in western Argentina are often below the temperature optimum of 7.3 • C of the chilling unit model for accumulating chilling (De Melo-Abreu et al., 2004). ...
Article
Detailed spring phenology studies are scarce in olive trees growing in non-Mediterranean climates despite crop expansion into new regions in the last few decades. Additionally, the vegetative phenology of olive trees has been little examined under any climate conditions. Thus, the aims of this study were to: (i) evaluate the timing of spring reproductive and vegetative phenological stages and their overlap for several olive cultivars growing under different air temperatures along a latitudinal gradient (29°–33° S) that included a range of altitudes (450–1,250 m asl) in western Argentina; and (ii) assess the potential relationships between the length (i.e., days) of some phenological phases and air temperature. All observations were performed during two growing seasons (2018–2019, 2019–2020). The temperature difference across the latitudinal-altitudinal gradient during the winter and early spring periods was between 4.2 and 6.0 °C. The separation of the first leaves (BBCH 11) most often occurred after inflorescence bud opening (BBCH 53) at warmer low latitude locations, but before BBCH 53 at cooler high latitude sites. A difference of 26 days in full flowering was found between extreme locations when considering both seasons. The variability of the reproductive stage dates was explained mostly by environmentally-related factors including location (71.7–95.2%) and season (0–18.1%) rather than by cultivar (2.8–6.6%). Nevertheless, cultivar responses did appear to depend on the climate conditions at different locations and growing seasons. The length of the inflorescence emergence phase (BBCH 53–60) decreased by 4.3 days/ °C as the mean air temperature during the phase increased. In contrast, the flowering phase length (BBCH 60–69) decreased with increasing mean air temperature during the phase up to 23 ºC, but increased above that temperature. These results should be useful for better timing of management practices and the development of phenological models that include non-Mediterranean environments.
... Olive growing system is the most extended perennial agroecosystem in the Mediterranean region, currently displaying significant environmental, economic and social functions (Mairech et al., 2021). This system has undergone important changes in the last decades, shifting gradually but significantly from traditional and low-density systems (<100 trees ha −1 ) to intensive (>200 trees ha −1 ) and highlyintensive (>800 trees ha −1 ) cropping systems in most producing countries of the Mediterranean basin (e.g., Kazes et al., 2020;Morgado et al., 2020;Ben Abdallah et al., 2021). ...
Article
Olive cultivation is the most important agro-ecosystem in the Mediterranean basin. Despite the remarkable intensification of this system (i.e., the use of high tree densities and large amounts of inputs), the environmental and socio-economic impacts of this transformation have been poorly studied to date. For this purpose, an integrated Life Cycle Sustainability Assessment framework is developed to assess the life cycle sustainability of innovative olive farming systems (intensive and highly-intensive) compared to traditional ones (conventional and organic) in Tunisia, one of the world's leading olive oil producers. The methodological framework consists of two parts: Life Cycle evaluation of olive systems (calculation of impact categories) and Muticriteria Decision Analysis integration (calculation of a sustainability score for each olive system). The results of the Multicriteria Decision Analysis indicate that stakeholders assign the highest priority to environmental aspects, followed by economic and social ones, especially, in the water resource depletion, internal rate of return, and human toxicity impact categories. According to the Life Cycle evaluation, fertilizers, soil management and harvesting are the agricultural practices with the highest impacts. In terms of sustainability, organic systems achieve better scores per ha and innovative systems per ton. Due to the critical water situation in Tunisia, the results suggest the need of: 1) improving the economic performance of rainfed olive farming systems, being the most prominent, by integrating farmers into cooperatives and encouraging conventional producers to get involved in the organic sector, and 2) mitigating the resource depletion impacts of intensive and highly-intensive systems through innovation based on integrated production (a certified system aimed to reduce environmental impacts derived from the use of chemicals in agriculture through the controlled use of production techniques), and limiting these systems to areas of low ecological vulnerability.
... Despite a certain number of papers focused on trying to assess the effects of the use of different water regimes on one or more different cultivars (Michelakis, 1990;Patumi et al., 1999;Moriana et al., 2003;Melgar et al., 2008;Zeleke, 2014;Tugendhaft et al., 2016) and/or different agronomical characteristics of the olive grove (Pastor et al., 2007;Trentacoste et al., 2015;Mairech et al., 2021) or cultivation techniques (D'Andria et al., 2008;Toplu et al., 2009;Zeleke et al., 2012;Rufat et al., 2014;Arampatzis et al., 2018), it is very difficult to find studies that try to evaluate it combined with different soils on the irrigation scheduling, the water status and the agronomical performance of the crop. ...
Article
To cope with the FAO motto ‘more food with less water’ it will be important to define the irrigation strategy not only according to the variety and type of olive grove but also based on the available soil. A certain number of papers focused on assessing the effects of different water regimes on different cultivars and/or agronomical characteristics of the grove while is very difficult to find studies that try to evaluate those effects of different soils. With the aim to give a contribution in elucidate the role of the soil characteristics on water management, two experimental trials have been carried on during the same two years in olive groves with same cultivar, very similar agronomical characteristics, and climatic conditions but with quite different soils, one shallow and silty and the other deep and silty-loamy. Compared water regimes were a dry control (T0) and two irrigated with restitution of 50% (T50WR) and 100% (T100WR) of the watering volume required to restore the full crop evapotranspiration. Main results are: (i) shoot growth did not differ among water regimes; (ii) leaf water potential decreased from the T100WR to the T0; (iii); T50WR and T100WR showed a very significant increase of yields, particularly different in terms of drupes (much higher in the deep soil) but much more similar in terms of oil between the two soils; (iv) oil content increase in TWR respect to T0, although somewhat less on the deep soil (22.81% in average for TWR treatments and 17.32% for T0, based on two years); (v) seasonal irrigation volumes were widely different between years (72 and 800% higher in the dry year respect to the rainy year for the shallow and the deep soil, respectively) but not so different between soils in the very dry year (23% higher in the deep soil).
... From a sustainability point of view, they have a low environmental impact with high social value, but they are generally unprofitable (i.e. they are based on the undervalorization of family worktime), although the earnings are often shared within small communities and families for which they represent an important (if not the only) source of income (Duarte et al., 2008;Palese et al., 2013). Notwithstanding, extensive, rainfed olive groves in dry areas have been forecasted as the most vulnerable to future climate changes (Mairech et al., 2021). ...
Article
Italian olive growing must aim at the transition to economically and environmentally sustainable management systems, linked to premium quality production and to a recognized and remunerated context of biodiversity conservation in compliance with the provisions of the European Union New Green Deal and United Nations Agenda 2030. To assist and facilitate companies in this step, a sustainability technical guide for the Italian olive oil supply chain has been developed, with reference to the four pillars of sustainability. The guide, consisting of 42 requirements, was submitted to 18 olive farms from 8 different Italian regions participating in this pilot study, to assess their level of total sustainability and to receive feedbacks throughout the drafting process. Taken as a whole, the companies have proved to be virtuous in meeting the requirements provided, with percentages of compliance ranging from 86 to 96% according to pillar and from 70 to 100% according to company and showed a remarkable spirit of collaboration and involvement in the construction of the guide. In this regard, the text is aimed to represent a participatory standard for Italian institutions and for other olive countries.
... The reductions in oil yield and the greater allocation of photoassimilates to vegetative growth than to fruit biomass with warming during the oil accumulation phase provide a first experimental approximation of olive tree response that should be of interest for modeling global change scenarios. Advanced sub-models of oil yield response to temperature are still needed for process-based models as suggested by Mairech et al. (2021). Additionally, changes in biomass partitioning due to temperature are not yet considered in some olive simulation models (Cabezas et al., 2020). ...
Article
Global warming and olive expansion to new regions have increased interest in understanding how air temperature affects olive production. Thus, the objective of this study was to evaluate the responses of oil yield components, total biomass production, and its partitioning to a moderate temperature increase (3–4 °C) during the oil accumulation phase in young olive trees of two olive cultivars (cvs. Arbequina, Coratina). Young, potted olive trees were actively heated by 3–4 °C in open top chambers under outdoor conditions compared to near-ambient temperature in similar control chambers. The trees were warmed from final fruit set to the end of the oil accumulation phase (5 months) in one (2014–15 or 2015–16) or in two consecutive seasons. Oil yield and its components were obtained from fruit harvested at the end of the season, while the vegetative dry biomass produced was estimated from destructive harvests of entire trees before and after a warming period. Glucose equivalents (GE) were also calculated for both oil yield and vegetative growth. Warming during the oil accumulation phase in one season led to some significant temperature x cultivar interactions for oil components. Individual fruit dry weight was reduced by warming to a greater extent in cv. Coratina than in cv. Arbequina, while fruit oil concentration was decreased more in cv. Arbequina. Significant decreases in oil yield were also observed for both cultivars. Warmed trees had a greater net leaf area increase than control trees when heated during the oil accumulation phase for one season (2014–15 or 2015–16), and allocated more GE to vegetative organs than to fruit in 2015–16. However, total tree biomass was not affected by warming. Warming trees the first season led to reduced flowering the following spring, and directly contributed to a temperature x cultivar interaction for fruit number during the second warming period with a 66% reduction in fruit number in warmed trees of cv. Arbequina and very low fruit number in all cv. Coratina trees. In contrast to warming during one season, total tree biomass GE decreased across cultivars when warming was performed in the oil accumulation phase for two consecutive seasons. The results suggest that cultivars should be carefully selected for new, warmer growing regions and that global warming may ultimately reduce oil yields and affect cultivar selection.
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Although the repaid development of China's apple industry heavily depends on excessive fertilizer-water-pesticide (FWP) inputs, little information is available that systematically evaluates environmental impacts, mitigation potential, and economical benefits of apple production systems in China. In this study, life cycle assessment (LCA) was conducted to elucidate environmental risks and mitigation potentials of rain-fed and irrigated apple production systems on China's Loess Plateau based on survey data from 847 farmers, and economic benefits were analyzed simultaneously. Results showed that irrigated orchards caused more severe environmental risks associated with energy depletion (ED), global warming potential (GWP) and acidification potential (AP) than those in rain-fed orchards, whereas an opposite was true for eutrophication potential (EP), human toxicity potential (HTP), aquatic toxicity potential (ATP) and soil toxicity potential (STP). ED and GWP occurred primarily in the agricultural material stage, while AP, EP, HTP, ATP, and STP occurred mostly in the orchard management stage. Optimized FWP management can markedly mitigate environmental impacts in both irrigated and rain-fed orchard systems. Synthetic fertilizer, because of production and field-associated emissions, was the greatest contributor to environmental impacts of an apple production system. An environmental pollution index (EPI) that integrated environmental categories was highest in conventional irrigated orchards (0.946), followed by conventional rainfed orchards (0.857), and optimized irrigated orchards (0.459), and the lowest EPI was in optimized rainfed orchards (0.389). Economic analysis revealed that the benefits of rainfed orchards were higher than those of irrigated orchards because of higher apple prices and lower labor costs. Optimized FWP management sharply decreased input costs, thereby substantially increasing net income in irrigated and rain-fed apple orchards. Overall, severe environmental risk and large mitigation potential co-exist in rain-fed and irrigated apple orchards on China's Loess Plateau. Integrated soil-crop-market management potentially exhibited considerable environmental and economic advantages, thereby efficiently developing high-quality apple production.
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Cover crops have long been proposed as an alternative soil management for minimizing erosion rates in olive stands while providing additional ecosystem services. However, the trade-off between these benefits and the competition for water with the trees makes the definition of optimal management practices a challenging task in semiarid climates. This work presents an improved version of OliveCan, a process-based simulation model of olive orchards that now can simulate the main impacts of cover crops on the water and carbon balances of olive orchards. Albeit simple in its formulation, the new model components were developed to deal with different cover crop management strategies. Examples are presented for simulation runs of a traditional olive orchard in the conditions of southern Spain, evaluating the effects of different widths for the strip occupied by the cover crop (Fcc) and two contrasting mowing dates. Results revealed that high Fcc resulted in lower olive yields, but only when mowing was applied at the end of spring. In this regard, late mowing and high Fcc was associated with lower soil water content from spring to summer, coinciding with olive flowering and the earlier stages of fruit growth. Fcc was also negatively correlated with surface runoff irrespective of the mowing date. On the other hand, net ecosystem productivity (NEP) was substantially affected by both Fcc and mowing date. Further simulations under future climate scenarios comparing the same management alternatives are also presented, showing substantial yield reductions by the end of the century and minor or negligible changes in NEP and seasonal runoff.
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The first Sustainable Development Goal expresses the global concern in poverty eradication. We looked at the theory of poverty reduction with a long-term perspective in mind to confirm the congruence of modern approaches and their compliance with the principles of sustainable development. Despite clear signs of targeting Sustainable development goals to the future, we have found that future poverty needs deep discussion. We researched legal acts, policies and scientific sources to prove the possibility and suitability of recognising future poverty as a valid form of poverty. We considered the main possible difficulties that will challenge initiatives of future poverty exhausting. Finally, we proposed several perspective directions of further research to include the future poverty concept into the agenda of governments and supranational organisations.
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Significance Inability to determine reliably the direction and magnitude of change in natural and agro-ecosystems due to climate change poses considerable challenge to their management. Olive is an ancient ubiquitous crop having considerable ecological and socioeconomic importance in the Mediterranean Basin. We assess the ecological and economic impact of projected 1.8 °C climate warming on olive and its obligate pest, the olive fly. This level of climate warming will have varying impact on olive yield and fly infestation levels across the Mediterranean Basin, and result in economic winners and losers. The analysis predicts areas of decreased profitability that will increase the risk of abandonment of small farms in marginal areas critical to soil and biodiversity conservation and to fire risk reduction.
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The flowering characteristics of plant species of economic interest and the influence of climate on them are of great importance considering the implications for fruit setting and the final harvest: Olive is one of the typical species of the Mediterranean habitat. We have investigated the timing of olive full flowering during the anthesis period and flowering intensity over a period of 20 years (1990–2009), in three major cultivation areas of the Mediterranean basin: Italy, Spain and Tunisia. The importance of these characteristics from a bioclimatic point of view is considered. The biological behaviour was studied to determine its main relationships with temperature and water availability, considering also the different sub-periods and the bio-climatic variations during the study period. The flowering dates and pollen emissions show different behaviours for the Spanish monitoring area in comparison with the other two olive cultivation areas. In the Italian and Tunisian areas, the flowering period over the last decade has become earlier by about 5 and 7 days, respectively, in comparison to the previous decade. Moreover, pollen emissions have decreased in Perugia (Italy) and Zarzis (Tunisia) over the period of 2000–2009, while in Cordoba (Spain), they showed their highest values from 2005 to 2009. The climate analysis has shown an increase in temperature, which results in an increase in the growing degree days for the growth of the olive flower structures, particularly in the more northern areas monitored. Although the olive tree is a parsimonious water consumer that is well adapted to xeric conditions, the increase in the potential evapotranspiration index over the last decade in the Italian and Tunisian olive areas might create problems for olive groves without irrigation, with a negative influence on the flowering intensity. Overall, in all of these Mediterranean monitoring areas, the summer water deficit is an increasingly more important parameter in comparison to the winter parameters, which confirms that the winter period is not as limiting as the summer period for olive tree cultivation in these Mediterranean areas.
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The study was carried out in a four-year-old super-high density olive grove in Central Italy to compare leaf gas exchanges of Spanish Arbequina and Italian Maurino olive cultivars. Overall, from mid July to mid November, Maurino had a slightly higher maximum light-saturated net photosynthetic rate (P Nmax) than Arbequina. The lowest and the highest P Nmax values were recorded at the end of July and in mid November, respectively. Current-season leaves showed similar or slightly higher P Nmax values than one-year-old leaves. During the day Maurino always had slightly higher values or values similar to Arbequina, with the highest P Nmax being in the morning. Maurino had similar or higher dark respiration rate (R D) values compared to Arbequina. During the day, in both cultivars the R D was lower at 9:00 than in the afternoon. The pattern of the photosynthetic irradiance-response curve was similar in the two genotypes, but the apparent quantum yield (Y Q) was higher in Maurino. In both cultivars intercellular CO2 concentration (C i) tended to increase when P Nmax decreased. The increase in C i corresponded to a decrease in stomatal conductance (g s). The transpiration rate (E) increased from mid July to the beginning of August, then decreased in September and increased again in November. Particularly in the morning, the current-season leaves showed similar or slightly higher E values than the one-year-old leaves. During the day, in both cultivars and at both leaf ages, E was higher in the afternoon. No effects on leaf gas exchanges due to the presence or absence of fruit on the shoot were found. Overall, there was satisfactory physiological adaptation for Arbequina to the conditions of Central Italy and for Maurino to the superintensive grove conditions.
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Olive (Olea europaea L.) is a widely spread tree species in the Mediterranean. In the last decades, olive farming has known major management changes with high economic and environmental impacts. The fast track expansion of this modern olive farming in these recent years casts doubts on the sustainability of such important tree plantation across the Mediterranean. In this work, we performed a spatial modelling analysis to investigate the implications of climate variability and farming management on the productivity and environmental performances of olive orchards around the Mediterranean. Implementation of this research is based on the use of OliveCan; a process-based model able to illustrate responses of water and carbon balances to weather variables, soil characteristics and management techniques enabling the comprehension of olive orchard dynamics under heterogeneous conditions of climate and agricultural practices. Four main intensification levels were adopted to reflect the main olive grove types from traditional to new intensive plantations: low density LD (100 trees ha⁻¹), medium density MD (200 trees ha⁻¹), high density HD (400 trees ha⁻¹) and super high density SHD (1650 trees ha⁻¹). Managements tested were intensification, water supply (rainfed, deficit and full irrigated) and the fate of pruning residues (exported or left on the soil). Two cases studies in two of the main Mediterranean olive-growing regions with contrasting environmental conditions, Tuscany and Jaen regions, focused on mitigation alternative managements for carbon sequestration. Results showed that olive orchards responses in terms of yield and Net Ecosystem Productivity (NEP) vary along with climatic conditions. Water supply was the main driver with a production function that varies for different atmospheric demands. Application of deficit irrigation proved to boost water use efficiency. Besides, intensification from LD to SHD, presented the greatest improvements, 28–73% for yield and 50–100% for NEP. The C sequestration potential of olive orchards was confirmed. In fact, soil organic carbon (SOC) increased continuously over 400 years of simulation, reaching a state of equilibrium. Moreover, intensification and irrigation improved total carbon sequestration. Management of incorporating pruning residues in the soil increased SOC of 10.5 t C ha⁻¹ for Tuscany and 10.8 t C ha⁻¹ for Jaen. Findings of this research enabled the identification of the main drivers influencing the productive and environmental performance of olive groves in the different Mediterranean sub-climates. Impacts of management innovations on olive farming sustainability were also quantified which may help improve production systems for a more sustainable olive cultivation.
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The olive tree is one of the most important crops in the Mediterranean basin. Given the strong climatic influence on olive trees, it becomes imperative to assess climate change impacts on this crop. Herein, these impacts were innovatively assessed, based on an ensemble of state-of-the-art climate models, future scenarios and dynamic crop models. The recent-past (1989-2005) and future (2041-2070, RCP4.5 and RCP8.5) olive growing season length (GSL), yield, growing season temperature (GST) and precipitation (GSP), potential (ETP) and actual (ETA) evapotranspiration, water demand (WD) and water productivity (WP), were assessed over southern Europe. Crop models were fed with an ensemble of EURO-CORDEX regional climate model data, along with soil and terrain data. For the recent-past, important differences between western and eastern olive growing areas are found. GSL presents a strong latitudinal gradient, with higher/lower values at lower/higher latitudes. Yields are lower in inner south Iberia and higher in Italy and Greece, which is corroborated by historical data. Southern Iberia shows higher GST and lower GSP, which contributes to a higher ETP, lower ETA and consequently stronger WD. Regarding WP, the recent-past values shows similar ranges across Europe. Future projections point to a general increase in GSL along with an increase in GST up to 3ºC. GSP is projected to decrease in Western Europe, leading to enhanced WD and consequently a yield decrease (down to-45%). Over eastern European, GSP is projected to slightly increase, leading to lower WD and to a small yield increase (up to +15%). WP will remain mostly unchanged. We conclude that climate change may negatively impact the viability of olive orchards in southern Iberia and some parts of Italy. Thus, adequate and timely planning of suitable adaptation measures are needed to ensure the sustainability of the olive sector.
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Experiments were performed in a high-density olive orchard to compare the effect of regulated deficit irrigation (RDI) at two different phenological stages with fully-irrigated trees (FI) over two years. Stress was imposed either prior to pit hardening (RDI 1) or after endocarp sclerification during the initial phase of oil accumulation (RDI 2). Fully irrigated trees received 2277 and 1648 m³ ha⁻¹ in 2012 and 2013, respectively, RDI 1 ones 76 and 53% of those volumes in 2012 and 2013, respectively (RDI 2 trees 48 and 67%). There were no differences in fruit set or return bloom due to the irrigation regime. At harvest differences in fruit size between FI and RDI treatments were significant only in the first year. The fruit yields of RDI 1 and RDI 2 trees were 70 and 81% of FI ones, respectively (means of two years), but the yield efficiency was similar across all treatments. The phenolic concentration in RDI 1 fruits was higher than that in fruits from trees subjected to the other water regimes. Verbascoside, 3–4 DHPEA-EDA, and oleuropein of RDI 1 fruits were higher in 2012 (only verbascoside in 2013). Oleuropein and 3–4 DHPEA-EDA of RDI treatments were higher than those of FI in 2013. Higher concentrations of biophenols were measured in oils from RDI 1 trees in both years, whereas FI and RDI 2 showed similar values. An early water stress was more effective to increase the phenolic concentration of olive oil compared with a late deficit or full irrigation.
Article
AdaptaOlive is a simplified physically-based model that has been developed to assess the behavior of olive under future climate conditions in Andalusia, southern Spain. The integration of different approaches based on experimental data from previous studies, combined with weather data from 11 climate models, is aimed at overcoming the high degree of uncertainty in the simulation of the response of agricultural systems under predicted climate conditions. The AdaptaOlive model was applied in a representative olive orchard in the Baeza area, one of the main producer zone in Spain, with the cultivar 'Picual'. Simulations for the end of the 21st century showed olive oil yield increases of 7.1 and 28.9% under rainfed and full irrigated conditions, respectively, while irrigation requirements decreased between 0.5 and 6.2% for full irrigation and regulated deficit irrigation, respectively. These effects were caused by the positive impact of the increase in atmospheric CO 2 that counterbalanced the negative impacts of the reduction in rainfall. The high degree of uncertainty associated with climate projections translated into a high range of yield and irrigation requirement projections, confirming the need for an ensemble of climate models in climate change impact assessment. The AdaptaOlive model also was applied for evaluating adaptation strategies related to cultivars, irrigation strategies and locations. The best performance was registered for cultivars with early flowering dates and regulated deficit irrigation. Thus, in the Baeza area full irrigation requirements were reduced by 12% and the yield in rainfed conditions increased by 7% compared with late flowering cultivars. Similarly, regulated deficit irrigation requirements and yield were reduced by 46% and 18%, respectively, compared with full irrigation. The results confirm the promise offered by these strategies as adaptation measures for managing an olive crop under semi-arid conditions in a changing climate.
Book
This textbook explains the various aspects of sustainable agricultures to undergraduate and graduate students. The book first quantifies the components of the crop energy balance, i.e. the partitioning of net radiation, and their effect on the thermal environment of the canopy. The soil water balance and the quantification of its main component (evapotranspiration) are studied to determine the availability of water to rain fed crops and to calculate crop water requirements. Then it sets the limitations of crop production in relation to crop phenology, radiation interception and resource availability (e.g. nutrients). With that in mind the different agricultural techniques (sowing, tillage, irrigation, fertilization, harvest, application of pesticides, etc.) are analyzed with special emphasis in quantifying the inputs (sowing rates, fertilizer amounts, irrigation schedules, tillage plans) required for a given target yield under specific environmental conditions (soil & climate). For all techniques strategies are provided for improving the ratio productivity/resource use while ensuring sustainability. The book comes with online practical focusing on the key aspects of management in a crop rotation (collecting weather data, calculating productivity, sowing rates, irrigation programs, fertilizers rates etc).
Article
To reduce greenhouse gas (GHG) emissions, the Kyoto Protocol identifies several activities that are closely related to land use, included into the category called Agriculture, FOrestry and Land Uses (AFOLU). In this framework, a multidisciplinary study has been performed about the carbon footprint of extra virgin olive (EVO) oil in Italy. This study aims to promote process innovation by implementing eco-friendly techniques and technologies along a more sustainable production chain. Life Cycle Assessment approach was used to quantify the environmental impacts during the entire life cycle, starting from olive cultivation up to transformation processes and packaging. Each operation was monitored in terms of energy and material flows; the data were normalized on the basis of 1 L of olive oil, chosen as functional unit. Forest survey methodologies were applied to estimate the biomass and the respective carbon stocked in olive tree permanent (trunk, branches, twigs and root collar, roots) and non-permanent components (prunings and fruits). Added value of this study was coupling the resulting impacts with carbon sequestrations in order to: i) estimate the net balance between the equivalent carbon dioxide (CO2-eq) emissions and absorptions; ii) identify the break-even point, after which the amount of sequestered carbon exceeds the energy investments linked to human activities. Results from the study give important contributions towards the preliminary assessment of potential benefits in terms of avoided CO2-eq from agriculture.
Article
Due to the severe increase projected in future temperatures and the great economic and social importance of olive growing for vast agricultural areas in the Mediterranean Basin, accurate climate change impact assessment on olive orchards is required. The aim of this study is to assess the flowering date and the impact of mean and extreme temperature events on olive flowering in southern Spain under baseline and future climate conditions. To that end, experimental data were obtained from ten olive genotypes: six well-known olive cultivars in the region, one cultivar, ‘Chiquitita’, obtained via conventional breeding, and threewild olives from the Canary Islands.Asite-specific model calibrationwas conducted resulting in satisfactory performance with an average error of 2 days for flowering date estimation under baseline and future climate conditions, and a RMSE equal to 5.5 days in the validation process. The outputs from 12 regional climate models from the ENSEMBLES European project with a bias correction in temperature and precipitation were used. Results showed an advance in the olive flowering dates of about 17 days at the end of the 21st century compared with the baseline period (1981–2010), and an increase in the frequency of extreme events around the flowering period. A spatial analysis of results identified the areas in southern Spain that are most vulnerable to climate change impact caused by the lack of chilling hours accumulation (areas located on the Atlantic coast and the south-eastern coast) and by the occurrence of high temperatures during the flowering period (areas located in the north and north-eastern areas of the Andalusian region).
Chapter
The components of the water balance (infiltration, deep percolation, evaporation from the soil surface, etc.) determine the amount of water available to the crop. Water flow in the soil occurs following the gradient of water potential and can be analyzed by the Richards equation, but there are simpler alternative methodologies to quantify the water balance components. Deep percolation can be estimated based on soil properties and water content above Field Capacity, depending also on soil evaporation and transpiration. Runoff is calculated based on the Curve Number and the amount of precipitation. For monthly values, effective rainfall can be calculated by the methods of FAO and SCS.
Article
Agriculture is not only appointed to produce food but has the potential to provide a range of ecosystem services (ES) depending on the management options adopted at field scale. Information on the impact of management practices adopted in fruit tree crops on ES is fragmented and often not fully codified. This paper focuses on some Mediterranean fruit tree crops i.e. peach (Prunus persica), apricot (Prunus armeniaca), olive (Olea europaea) groves and vineyards (Vitis vinifera), and links mainly soil processes and functions to the provisioning, regulating and sociocultural ES. The effects of field practices (e.g., tillage/no-tillage, cover crops, retention/burning of pruning residues, mineral/organic fertilization) on manageable soil properties (e.g., porosity, organic carbon content, composition of microbial community) and related functions (e.g., supply of nutrients, water storage, soil stability, above-ground biodiversity) were examined.
Article
The concentration of atmospheric carbon dioxide at Mauna Loa Observatory, Hawaii is reported for eight years (1964-1971) of a long term program to document the effects of the combustion of coal, petroleum, and natural gas on the distribution of CO, in the atmosphere. The new data, when combined with earlier data, indicate that the annual average CO, concentration rose 3.4 '% between 1959 and 1971. The rate of rise, however, has not been steady. In the mid-1960's it declined. Recently it has accelerated. Similar changes in rate have been observed at the South Pole and are evidently a global phenomenon.
Article
This book contains 17 chapters on the biophysical processes occurring at the interface between forest ecosystems and the atmosphere. It brings together topics such as the role of stomata in regulating water fluxes to the atmosphere, radiation penetration into forest canopies, forest meteorology, mesoscale modelling, remote sensing of canopy characteristics of forests, neural network predictions of carbon sequestration in Europe, and policy making and forestry. This book also celebrates the achievements of Professor Paul Jarvis, a highly distinguished environmental biologist and forest physiologist, who devoted his career to understanding these relationships. The individual chapters are based on papers presented at the meeting Forests at the Land-Atmosphere Interface, which was held in his honour at the University of Edinburgh on 17-19 September 2001. This book will be of significant interest to researchers in forestry, ecology, environmental sciences and natural resources.
Article
Irrigation is one of the most important means of increasing olive oil production but little information exists on the responses of olive to variable water supply. Five different irrigation strategies, full irrigation, rain fed, and three deficit irrigation treatments were compared from 1996 to 1999, in Cordoba, southern Spain, to characterize the response of a mature olive (Olea europaea L. 'Picual') orchard to irrigation. Crop evapotranspiration (ETC) varied from less than 500 mm in the rain fed to ≈900 mm under full irrigation. The deficit irrigation treatments had ETC values that ranged from 60% to 80% of full ETC depending on the year and treatment. Water relations, and oil content and trunk growth measurements allowed for the interpretation of yield responses to water deficits. In a deficit irrigation treatment that concentrated all its ETC deficit in the summer, stem water potential (ψx) decreased to -7 MPa but recovered quickly in the fall, while in the treatment that applied the same ET deficit progressively, ψx was never below -3.8 MPa. Minimum ψx in the rain fed treatment reached -8 MPa. Yield (Y) responses as a function of ETC were calculated for biennial yield data, given the alternate bearing habit of the olive; the equation are: Y = -16.84 + 0.063 ET -0.035 × 10-3 ET2, and Y = -2.78 + 0.011 ET - 0.006 × 10-3 ET2, for fruit and oil production respectively, with responses to ET deficits being similar for sustained and regulated deficit irrigation. The yield response to a deficit treatment that was fully irrigated during the bearing year and rain fed in the nonbearing year, was less favorable than that observed in the other two deficit treatments.
Article
The models developed for simulating olive tree and grapevine yields were reviewed by focussing on the major limitations of these models for their application in a changing climate. Empirical models, which exploit the statistical relationship between climate and yield, and process based models, where crop behaviour is defined by a range of relationships describing the main plant processes, were considered. The results highlighted that the application of empirical models to future climatic conditions (i.e. future climate scenarios) is unreliable since important statistical approaches and predictors are still lacking. While process-based models have the potential for application in climate-change impact assessments, our analysis demonstrated how the simulation of many processes affected by warmer and CO2-enriched conditions may give rise to important biases. Conversely, some crop model improvements could be applied at this stage since specific sub-models accounting for the effect of elevated temperatures and CO2 concentration were already developed.
Article
The Mediterranean basin is the largest world area having specific climatic conditions suitable for olive cultivation, which has a great socio-economic importance in the region. However, the Mediterranean might be particularly affected by climate change, which could have extensive impacts on ecosystems and agricultural production. This work focussed on the climate change impact on olive growing in the Mediterranean region considering the possible alterations of cultivable areas, phenological dates, crop evapotranspiration and irrigation requirements. Monthly climate data, with a spatial resolution of 0.25° × 0.25° (latitude by longitude), have been derived from Regional Climate Models driven by ECHAM5 for the A1B scenario of the Special Report on Emissions Scenarios (SRES). The data used in the analysis represented two time periods: (i) present, called year 2000 (average values for the period 1991–2010), and (ii) future, called year 2050 (average values for the period 2036–2065). The areas suitable for olive cultivation were determined using the temperature requirements approach known as the Agro Ecological Zoning method. Crop evapotranspiration and irrigation requirements were estimated following the standard procedure described in the FAO Irrigation and Drainage Paper 56. Results showed that the potentially cultivable areas for olive growing are expected to extend northward and at higher altitudes and to increase by 25% in 50 years. The olive flowering is likely to be anticipated by 11 ± 3 days and crop evapotranspiration is expected to increase on average by 8% (51 ± 17 mm season−1). Net irrigation requirements are predicted to increase by 18.5% (70 ± 28 mm season−1), up to 140 mm in Southern Spain and some areas of Algeria and Morocco. Differently, effective evapotranspiration of rainfed olives could decrease in most areas due to expected reduction of precipitation and increase of evapotranspirative demand, thus making it not possible to keep rainfed olives’ production as it is at present.
Article
In recent years, the role of Life Cycle Assessment (LCA) of products and processes has increased in importance, since it is the best technique to quantify environmental impacts associated with a process or product. The study was carried out in an olive grove located in Central Italy with “Leccino” cultivar. The olive grove was established in year 2000 with a planting distance of 5.5 × 5.5 m, trained to the vase system, under dry conditions. The same methodology used for forestry trees (“model tree”) was adopted to estimate the biomass and the respective carbon stock of the below-ground and above-ground parts of the olive tree as well as quantification of the non-permanent components periodically removed, i.e. fruits and prunings. The environmental impacts associated with management processes were evaluated according to LCA standards (UNI EN ISO 14040 and 14044). In relation to the impact on climate change, the CO2 sources and sinks were calculated in order to obtain the net carbon stock of the olive grove. These data were confirmed by experimental measurement of the tree biomass in three representative olive trees. The treatments and processes that had the greatest impact were identified and the individual phases and materials were then analysed in order to propose possible actions for reducing emissions throughout the entire olive grove life cycle. Removals and emissions were compared on a time scale, in order to identify the break-even point. The results allow to assess the carbon footprint of an olive grove, at different stages of its life cycle, as a support tool for creating a sustainable production chain in the olive sector. The paper proposes a methodological approach that can be adopted also in other olive groves with different horticultural management models.
Article
Projected changes of extreme precipitation in the Mediterranean area up until the end of the 21st century are analysed by means of statistical downscaling. Generalized linear models are used as downscaling technique to assess different percentile-based indices of extreme precipitation on a fine-scale spatial resolution. In the region under consideration extreme precipitation is related to anomalies of the large-scale circulation as well as to convective conditions. To account for this, predictor selection encompasses variables describing the large-scale circulation (geopotential heights of the 700 hPa and 500 hPa levels, u- and v-wind components of the 850 hPa level) as well as thermo-dynamic parameters (specific humidity of the 850 hPa and 700 hPa levels, Showalter-Index, convective inhibition). In the scope of the statistical downscaling approach a specific statistical ensemble technique is applied in order to allow for non-stationarities in the predictors–predictand relationships. Consequently, the statistical ensembles include a range of possible future evolutions of extreme precipitation. Two different emission scenarios (A1B and B1), multiple runs for each scenario, and output of two different general circulation models (ECHAM5 and HadCM3) are applied to assess extreme precipitation under enhanced greenhouse warming conditions. The results yield mainly decreases over many parts of the Mediterranean area in spring. In summer increases are assessed around the Tyrrhenian Sea, the Ionian Sea, and the Aegean Sea, whereas decreases are projected for most of the western and northern Mediterranean regions. In autumn reductions of heavy rainfall occur over many parts of the western and central areas. In winter distinct increases are widespread in the Mediterranean area. Beyond the assessments using all predictors it is shown in the present contribution that different predictor variables can lead to varying statistical downscaling results. It points to distinct impacts of the change of specific atmospheric conditions on local extreme precipitation.
Article
The wide variability and complexity of olive orchards makes it difficult to provide solutions to the numerous management questions using a pure experimental approach. In this paper we calibrate and validate a simple model of olive orchard productivity based on the Radiation-Use Efficiency (RUE) concept of Monteith. A calibration experiment was performed in Cordoba from 1998 to 2001 with drip-irrigated olive trees cv. ‘Arbequina’. Destructive samples of 18 trees and non-destructive measurements on 80 trees were used to determine RUE and dry matter partitioning coefficients. Validation experiments were performed in 18 drip-irrigated orchards of seven locations in Southern Spain, including two cultivars (‘Arbequina’ and ‘Picual’). Average RUE was 0.86 g dry matter (MJ PAR)⁻¹ which is equivalent to 1.56 g glucose (MJ PAR)⁻¹. Aboveground accumulated biomass was allocated equally to fruits and vegetative growth, which in turn was partitioned into 30% for leaves and 70% for stems, branches and trunk. The fraction of oil in fruits was 0.38 which implies that the average ratio oil yield/intercepted PAR, which is an equivalent RUE for oil production (ɛo), is 0.17 g oil (MJ PAR)⁻¹. The prediction of oil yield as the product of 0.17 and total intercepted PAR was tested successfully in the validation experiments (relative RMSE = 0.26). Errors of this simple model were partly due to alternate bearing and partly to a decrease in ɛo as canopy size increases, which deserves further research. The concept of ɛo may be also useful for the evaluation of alternate bearing in olive trees.
Article
Atmospheric CO2 measurements from the NOAA Geophysical Monitoring for Climatic Change program at the Mauna Loa Observatory are presented for the period 1974-1985. Hourly and daily variations in CO2 concentration due to local sources and sinks and the long-term increase in CO2 are examined. IT is shown that the seasonal cycle was increasing at a rate of 0.05 + or - 0.02 ppm/yr. The average CO2 growth rate for the period is 1.42 + or - 0.02 ppm/yr. The fraction of CO2 remaining in the atmosphere from fossil fuel combustion is found to be 59 percent.
Article
Aim This paper aims to project areas of olive cultivation into future scenarios. Accordingly, we first asked the question whether global circulation models (GCMs) are able to reproduce past climatic conditions and we used historical ranges of olive cultivation as a palaeoclimate proxy. Location The Mediterranean basin. Methods We used an ecological model, calibrated and validated for modern times, to test the reliability of a general circulation model (NCAR-CSM GCM) in reproducing past ranges of olive tree cultivation inferred from the literature, archaeo-botanical investigations and fossil pollen analyses. Results The re-constructions of olive growing areas, obtained for the Medieval Climate Anomaly (MCA, 1200-1300 AD) and the Little Ice Age (LIA, 1600-1700 AD) by coupling the outputs of NCAR-CSM to the ecological model, were in agreement to those observed. Simulations of olive growing areas for future time-windows showed that a northwards expansion of the species is expected to occur by 2100. Main conclusions These results demonstrate that the NCAR-CSM can provide an accurate reconstruction of past climate with results sensitive to climate forcing factors and thus, it is more likely to give reliable projections for the future. Additionally, the warming and drying conditions expected in the coming decades may determine changes across the Mediterranean basin that is unprecedented.
Article
The olive tree is so typical of the Mediterranean climate that its presence in a territory qualifies the climate of this as Mediterranean. Many clues indicated that in the past olive cultivation limits moved northward or southward in the Northern Hemisphere according to warmer or cooler climate, respectively. This makes the olive tree cultivation area a possible biological indicator of changes in climate and the identification of the climatological parameters that limit its cultivation plays an important role for climate change impact assessment. In this work, three different approaches were compared, with the aim to compare methodologies suited to predict olive tree distribution over the Mediterranean basin: two classifiers (Random Forest, RF and an Artificial Neural Network, ANN) and a spatial model to infer climatic limiters of plant distribution (CLPD). These methodologies were applied within a framework including a geographical information system (GIS), which spatially defined olive tree cultivated area, and climatological informative layers (average temperature and cumulated rainfall, 50km×50km), which were used as predictor variables. The results indicated that RF achieved on the whole, the lowest classification error (113 misclassified cases on 1906 test cases) followed by ANN (128 cases) and CLPD (153 cases). A validation test, performed over areas out of the Mediterranean basin where olive tree is cultivated (i.e. California and Southern Australia), confirmed the goodness of the RF fitted model in predicting olive tree suitable areas. In general, climatic predictor variables of the coldest and warmest periods of the year were the most significant in determining the limits of suitable olive cultivation area for these methodologies. In particular, temperature of January and July and rainfall of October and July were the climatic predictor variables having highest significance for both RF and ANN. Temperature of January >2°C, of July >20°C and cumulated annual rainfall >240mm were the bounds found in the spatial model. The fitted RF model, coupled with the results of both Regional and General Circulation Model, was finally proposed to assess climate change impact on olive tree cultivated area in the Mediterranean basin.