Olive Fields Research Articles

Arbosana Olive Is Self-Incompatible, but Inter-Compatible with Some Other Low-Vigor Olive Cultivars

Trendy high-density olive fields are often monovarietal orchards, mostly using the cultivar Arbequina. However, Arbequina shows a strong self-incompatibility response, and its yields depend on wind cross-pollination, which is not always available. With the aim of finding suitable self-compatible cultivars that can replace Arbequina, we evaluated pollen–pistil interaction, fruit set and seed paternity in Arbosana under different pollination treatments: self-pollination, open-pollination and three cross-pollination treatments: × Arbequina, × Sikitita and × Koroneiki. All these cultivars are low-vigor cultivars suitable for high-density orchards, making them potential pollinizers for Arbosana. The results show that Arbosana is also self-incompatible with a strong reduction in fruit set due to a lower fertilization level caused by a strong inhibition of pollen tube growth in self-pollinated flowers. Seed-paternity analyses confirmed the self-incompatibility response of Arbosana and suggest that some fruit obtained in bagged shoots under self-pollination were, in fact, a product of cross-fertilization. In conclusion, we recommend against the use of Arbosana in large monovarietal orchards. On the contrary, good results were obtained under cross-pollination with Sikitita, Arbequina and Koroneiki pollen, allowing us to recommend them as pollinizers for Arbosana in appropriate pollination designs. This is the first time Arbosana self-incompatibility has been reported.

Woodland loss differently affects seed dispersal by resident and migratory avian frugivores in olive grove-dominated landscapes

Seed dispersal by frugivores is a key ecological process underpinning the functionality of woodland patches and their capacity to maintain biodiversity in agricultural landscapes. Resident and migratory avian frugivores differ in temporal span of their local occurrence, as well as in mobility and territoriality. However, whether landscape homogenization by agriculture affects seed dispersal by avian frugivores differing in migratory strategy remains largely unexplored. We hypothesized a positive role of woodland patches on avian frugivore abundance and seed-dispersal frequency, and a differential impact of woodland loss and landscape simplification on resident and migratory frugivorous birds. We tested these hypotheses in 20 farms distributed along a gradient of woodland loss and olive cropland expansion in south Spain, considering woodland patches and olive fields as two habitats to survey avian frugivore abundance and frequency of seed dispersal. We confirmed that both the abundance and seed-dispersal frequency of avian frugivores were higher in woodland patches than in olive fields, and also that both decayed with decreasing woodland cover. This was largely mediated by a few European (winter) migrants and secondarily by some resident species. However, the woodland patches were unable to intercept sub-Saharan (summer) migrants in sufficient numbers as to make their contribution to dispersal of summer fruits meaningful. Woodland patches with higher seed-dispersal function were located predominantly in landscapes with high woodland cover and/or fruit availability. Moreover, a relatively high woodland cover in the landscape enhanced the seed dispersal function in woodland patches through a balance between high overall frugivore abundance and dispersal frequency, and some increased activity of resident and summer migrants. Our results also inform that the presence of particularly fruit-rich woodland patches can compensate the woodland cover required to maintain the function by enhancing the frequency of seed dispersal of all migratory groups. In contrast, to maintain the function of fruit-poor woodlands their cover at landscape scale should increase. Preserving and restoring woodland patches at landscape scale and enhancing their abundance and diversity of fruits could boost the activity of different disperser groups and their functional complementarity across agricultural landscapes.

The Effect of Beneficial Autochthonous Microorganisms (Bams) on the Chemical Quality of Agricultural Soils and Olive Production in the Wilaya of Tlemcen (Western of Algeria)

Abstract Beneficial Autochthonous Microorganisms (BAMs) are a multi-purpose technology that has already been used in Latin America and Southeast Asia but is still unknown in Africa and particularly Algeria. The aim is to examine the effect of BAMs on agricultural soils and olive fields. The study was carried out in two degraded olive fields located in the Oued Tafna basin west of Tlemcen (The Semi-arid region in Western Algeria). The objective is to evaluate the effectiveness of BAMs on the chemical characteristics of the soils, particularly in terms of organic matter (MO), pH, electrical conductivity (EC), total limestone (CaCO3), moisture, organic carbon (C) and olive production and its weight. Statistical analysis (Independent Test) between all groups (treated and controls) showed a significant difference, in conductivity (EC) where we recorded “0.214±0.03μs /cm “ in treated soils vs. “0.198±0.029μs/cm “ in control soils a different statistical significance was recorded for the other parameters, however, it was observed that there is a relative increase in these parameters in the soils of the treated groups such as carbon (C): “2.85±1.06%” organic matter (MO): “4.91± 1.83%”, “pH=7.81±0.225”, “CaCO3 27.76±4.99% and a decrease in humidity “15.11±3.77%” compared to control soils. The results of statistical analyses (Mann-Whitney Test and Suite Test) of olive production showed a clear alternation (every other year) in fruit production in the control group and a positive effect of BAMs on olive production in the treated group, with a slight increase of production (19 kg in 2019 vs. 30 kg in 2020), but without any significant difference regarding the weight of the fruit between the two sessions. However, a highly significant difference “p=0.00<0.001” in fruit weight was noted between the treated groups “3.908g” and “5.70g” and the control ones “4.40g “ and “5.00g” in 2019 and 2020 respectively. The use of MAB is an interesting technique to restore the chemical properties of degraded soils, and increase olive tree production. To achieve more reproducible results (in terms of quantity and quality), sufficient doses of these BAMs and periodicals must be added to provide a good nutritional supplement and reduce farmers’ use of pesticides and mineral fertilizers.

Implementing Sentinel-2 Data and Machine Learning to Detect Plant Stress in Olive Groves

Olives are an essential crop for Greece and constitute a major economic and agricultural factor. Diseases, pests, and environmental conditions are all factors that can deteriorate the health status of olive crops by causing plant stress. Researchers can utilize remote sensing to assist their actions in detecting these sources of stress and act accordingly. In this experiment, Sentinel-2 data were used to create vegetation indices for commercial olive fields in Halkidiki, Northern Greece. Twelve machine learning algorithms were tested to determine which type would be the most efficient to detect plant stress in olive trees. In parallel, a test was conducted by testing 26 thresholds to determine how setting different thresholds for stress incidence affects model performance and which threshold constitutes the best choice for more accurate classification. The results show that among all tested classification algorithms, the quadratic discriminant analysis provided the best performance of 0.99. The stress incidence threshold used in the current case to generate the best-performing model was 6%, but the results suggest that setting customized thresholds relevant to specific cases would provide optimal results. The best-performing model was used in a one-vs.-rest multiclass classification task to determine the source of the stress between four possible classes: “healthy”, “verticillium”, “spilocaea”, and “unidentified”. The multiclass model was more accurate in detection for the “healthy” class (0.99); the “verticillium” and “unidentified” classes were less accurate (0.76); and “spilocaea” had the lowest score (0.72). Findings from this research can be used by experts as a service to enhance their decision-making and support the application of efficient strategies in the field of precision crop protection.

Blockchain-Based Supply Chain System for Olive Fields Using WSNs.

The agricultural domain in developing countries is mostly dictated by archaic rules based on traditions and inherited practices. With the evolution of digitalization and technology, it seems essential to apply new technologies to the agricultural field. Among the technologies to be exploited in agriculture, we mention sensors, IoT, WSN, cloud, blockchain, etc. We talk about smart agriculture in this case. In this paper, we propose a platform secured by blockchain for monitoring and securing production. This platform uses IoT connected sensors to track and save data. Our system is used to monitor the production process of olive trees. The goal is to track everything that enters and leaves our olive tree production from fertilizers, insecticides, and fortifiers to olives, trimming etc. The blockchain via its decentralized system allow a secure, irreversible, and clear monitoring. A dashboard allow us to highlight the changes while facilitating the work of farmers. Our prototype will be embedded via a Raspberry Pi 4 platform.

Repellent Activity of Vanillin Derivatives and Monoterpenes to Olive Weevil

Olive weevils, Pimelocerus (Dyscerus) perforatus Roelofs, utilize olive trees as a host plant. The adult female uses an elongated snout to puncture the trunk and lay one egg a day, resulting in dozens of eggs over its lifetime. The hatched larvae grow by eating the olive trunk. When olive trees die due to feeding damage, olive productivity is seriously impaired. Since there is no effective pesticide for olive weevils so far, the authors aimed to develop a repellent for adult olive weevils from the viewpoint of integrated pest management. We prepared a measurable apparatus for the repellent action against olive weevils and screened chemical substances by using the apparatus. When the repellent activity was measured using vanillin and its derivatives, a clear repellent effect could be confirmed for two types of vanillin derivatives, such as o-vanillin, and 2-hydroxy-4-methoxybenzaldehyde. In addition, when the repellent activity against olive weevils was measured using monoterpenes, four types of acyclic monoterpenes, geraniol, β-citronellol, citral, and linalool, and three types of monocyclic monoterpenes, (-)-limonene, (+)-limonene, and (-)-menthol, and a bicyclic monoterpene, (1R)-(+)-α-pinene, were found to have dose-dependent repellent activity with statistical significance. In the future, it is expected that the formulation for applying the repellent substances to olive trees and the study of their practicality in olive fields will progress.

Use a Mixture of Wood Lignin and Some Fertilizer to Improve the Chemical Content of Olive Seedlings

The study was conducted during the season 2021-2020 and was distributed on two main axes: the first is to extract the lignin from the trees of Milea azedarach L. The extraction process was carried out in the chemistry laboratory belonging to the College of agricultural technology/Mosul according to the basic method used in the manufacture of paper and paper paste. the second is the selection of one of the olive fields in the Nineveh forest nursery belonging to the Department of Agriculture of Nineveh and combating desertification, to find out the effect of the extract of lignin added to types of fertilizers and the overlap between them in the chemical content of the leaves. The three-factor experiment with three iterators was designed according to the design of complete random sectors (RCBD), This experiment was carried out on her from the cuttings of olive cultivar Arbequina if the factor on the concentrations of the extract accent (0,60%), while the second three types of fertilizer(compound fertilizer NPK, fertilizer nitrogen of Urea, compost mixture (Urea50%+NPK50%), the second factor was four levels of the proportion of mixing shellac with the quality( 0,10%,15%,25%), Proceedings of the spraying process early in the morning until the pallet is full, using the spray device sales capacity 2 liters. The results of the study showed that the treatment of seedlings with lignin extract concentration (60%) has a significant effect on both the content of the leaves (percentage of nitrogen, percentage of phosphorus, percentage of potassium), while the treatment with compound fertilizer was superior and at a concentration of 129 g.l-1significant in the percentage of carbohydrates, and to spray the olive seedlings with nitrogen fertilizer (Urea) especially the concentration of 10 g.l-1 While the treatment with mixed fertilizer (NPK 50%+ Urea 50%) showed significant effects in most of the studied chemical qualities, as for the two-and three-way interactions of the study transactions gave a significant effect in improving all the chemical qualities of the leaves and various concentrations, which led to the emergence of positive effects on the seedlings of olive trees for the transactions understudy, which led to increased activity and growth of seedlings throughout the research period.

Persistence of Seed Dispersal in Agroecosystems: Effects of Landscape Modification and Intensive Soil Management Practices in Avian Frugivores, Frugivory and Seed Deposition in Olive Croplands

Farming impacts animal-mediated seed dispersal through mechanisms operating on at least two spatial scales. First, at the landscape scale, through habitat loss and land conversion to agriculture/livestock grazing, and second, at the farm scale, via a local intensification of agricultural practices. These two scales of farming impact seed dispersal function but have rarely been integrated. In particular, studies evaluating the effect of agriculture on the seed dispersal function of frugivorous birds in Mediterranean ecosystems are lacking. This study evaluates the role of landscape transformation, from fruit-rich woodland habitats to olive grove landscapes, together with local intensive practices of soil management on the persistence of the seed dispersal function for Mediterranean fleshy-fruited plants in olive landscapes of south Spain. We used bird censuses, mist-nets, and seed traps to characterize avian frugivore assemblages, frugivory, and seed deposition in the seminatural woodland habitat (SNWH) patches and olive fields of 40 olives farms spanning 20 localities distributed across the whole range of olive cultivation in Andalusia (southern Spain). We found that despite the remarkable dispersal function of olive grove landscapes, avian frugivore abundance and diversity, frugivory, and seed arrival decreased in olive fields compared to SNWH patches. Likewise, SNWH cover loss and/or olive growing expansion decreased avian frugivory and seed arrival. Interestingly, the habitat effects in the olive farms often depended on the landscape context. In particular, less diverse fruit-eating bird assemblages pooled in SNWH patches as olive grove cover increased or SNWH decreased in the landscape, while remaining relatively invariant in the olive fields. Finally, compared to conventional intensive agriculture, low-intensity management increased frugivory and seed deposition. We conclude that olive fields are less permeable to frugivores than expected due to the agroforest-like nature of these landscapes and that the presence of SNWH patches is crucial for the maintenance of frugivory and seed dispersal in agricultural landscapes. These results evidence that woodland habitat loss by olive expansion and intensive practices seriously threaten the dispersal service in olive-dominated landscapes. Maintenance, restoration, and promotion of woodland patches should be prioritized for the conservation of seed dispersal service and for enhancing the functional connectivity in human-shaped olive landscapes.

Pathogenicity of Fusarium Solani And Ilyoncteria Macrodidyma on Olive Seedlings Roots And The Efficacy of Soil Microbial Community against Infection

A total of six olive fields were inspected randomly in three locations (Sartank, Sharia and Qasrook) at Duhok province. The highest severity (40%) and incidence (83%) of olive tree wilting and dieback were recorded in Sharia while the lowest severity was in Sartank (35%).  The predominant fungi in this study were Fusarium solani and Ilyoncteria macrodidyma. The occurrence percentage of isolated fungi varied between locations.  F.solani was the most frequent (53.3 %) on Qasrok, while I. macrodidyma was recorded at low frequencies (16.6%). F. solani was isolated by 29.4% and 27.2% in Sharia and Sartank respectively. Disease severity of F. solani in aerial part of olive seedlings during May, July, and September was 22.66%, 40.33% and 67% respectively significant differences, while  was 24.67%, 31%, and 45.33by I. macrodidyma % respectively. Pathogenicity after five months showed high root infection by F. solani (100%) incidence and (68.20) severities. The reduction in wet and dry weight of the green part was 25.75% and 36.64% and in roots system was 59.29% and 50.99% respectively. I macrodidyma showed (100 %) disease incidence and (46.70%) severity in root system. The reduction in wet and dry weight of the green part was 18.23%, 18.80%, while in olive root was 34.66%, 29.32% respectively. Trichoderma harzianum rapidly stopped F. solani mycelia growth, and showed (64%) inhibition, while Gliocladium sp inhibited the radial growth of F. solani to (31%) and Aspergillus niger, (22%) inhibition respectively. High in vitro inhibition of I. macrodidyma was observed by T. harzianum (77%). The results of dual culture method revealed that T. harzianum completely overgrew the pathogen I. macrodidyma and was placed in class1 according to Bells scale; whereas Penicillium sp. parasitized the tested pathogen up to two-thirds of the medium and were placed in class 2. The antagonism against F. solani showed the overgrew of T. harzianum up to two thirds of the medium and were placed in class 2, while the pathogen colonized at least two-thirds of the medium and overgrew the Gliocladium sp and Aspergillus niger colonies and were placed in class 4. Penicillium sp. colonized one-half of the medium and was placed in class 3

EFA-CFA integrated approach for groundwater resources sustainability in agricultural areas under data scarcity challenge: case study of the Souassi aquifer, Central-eastern Tunisia

Water resources become more and more threatened by the increasing request related to the population growth, especially in agricultural regions. This article focused on the design of a geo-model monitoring network controlling groundwater quality in the fast-growing agricultural area of Souassi, Central eastern Tunisia. The studied area is known for its dry climate conditions and information scarcity while they are most needed. In this case, the integrated approach based on the Exploratory Factor Analysis coupled to the Confirmatory Factors Analysis and geostatistics were performed in order to detect the most relevant factors intervening in the groundwater quality and their spatial variability in the shallow aquifer of Souassi. This investigation is based on data set of nine parameters (EC, Ca, Mg, Na, K, HCO3, SO4, Cl and NO3) determined in 30 samples from wells tapping the shallow aquifer of Souassi. The PCA results allowed illustrating that the groundwater quality in Souassi shallow aquifer is affected by both natural and anthropogenic factors. Developing the SEM led to identifying the most meaningful factors controlling the water mineralization. The geospatial interpolation using kriging technique enabled us to locate areas with high salinity values corresponding to the natural discharge zone of the aquifer as well as areas with high rate of nitrate coinciding essentially with olive fields in the central zone. Under limited database, the results allow highlighting the risk zones in the aquifer. This could assist in establishing sustainable agricultural activities while helping to solve environmental degradation of water resources in the study area.

USING GOOGLE EARTH™ AND GEOGRAPHICAL INFORMATION SYSTEM DATA AS METHOD TO DETECT URBAN SPRAWL AND GREEN SPACES FOR BETTER WELL BEING CASE OF A COASTAL LANDSCAPE

Coastal landscapes are facing a huge challenge to manage the spatial extension of their built-up area at the expense of the reduction of natural and cultivated areas. This is the case of Hergla city, located in the southern part of Hammamet Gulf, Tunisia. This paper firstly highlights changes of LULC in Hergla city, between 2007 and 2017 using a supervised classification of Landsat images. The evolution of built-up area between 2002 and 2020 is examined expending Google Earth images. Lastly, the geolocalization of green spaces are provided. Then, the superposition of all these analyzes will be used to propose a landscaping for a better human well-being. Finally, this research indicates the importance of analyzing LULC change at multiple scales; it revealed that built-up area has been increased and olive fields reduced from 64 % in 2007 to 30.2 %in 2017. It shows, too, an important urban expansion from 39.9 Ha in 2002 to 48.3 Ha in 2020. However, the green spaces are concentrated in the North and middle part of the city and a proposal for the development of an urban park on the south side will help to balance the spatial distribution of green spaces in this area and ensure better human well-being.

Comparing microbial community heterogeneity in soil under organic and conventional agricultural system cultivated with olive and peach trees in three fields differ with age at Al-Jouf Saudi Arabia

This research study was carried out at Al-Jouf region, north eastern Saudi Arabia, to investigate the differences in microbial community and density of microorganisms in the rhizosphere of olive (Olea europaea) and peach (Prunus persica) tree fields subjected to growth under organic and conventional agriculture systems. The soil analytical processes were conducted in three olive and three peach fields (9, 17, 27 years old and 20 ha in area) under organic fertilization, and three similar olive and peach fields under conventional fertilization system. The results indicated significant variations between the two agricultural systems in rhizosphere content of microbial and mycorrhizal colonization%. The highest percentages of actinomycetes, total fungi and bacteria (PSM) were recorded in the organically agricultural system (OAS) in olive fields in comparison to conventionally agricultural system (CAS). Regarding field ages OAS dominated CAS in total number of fungi under all olive fields ages, while under peach fields fungi counts were significantly high under CAS compared to OAS. Under peach fields OAS dominated giving the highest actinomycetes and bacteria and CAS dominated by giving the highest CFU and fungi count. The significantly highest counts of CFU and bacteria were attained under conventional farming system (CAS) in all of the different aged field compared to OAS. Actinomycetes and bacteria in young fields were significantly high under CAS, while in old fields actinomycetes and fungi counts were the highest under OAS.

Genetic Diversity of Verticillium dahliae Populations From Olive and Potato in Lebanon.

Verticillium dahliae is widely distributed in potato and olive fields in Lebanon, causing serious economic losses. However, little is known about the inoculum source, population structure, and genetic diversity of the pathogen or the mechanisms of dissemination within Lebanon. To understand the population structure, a total of 203 isolates sampled from olive (n = 78) and potato (n = 125) were characterized for species, mating type, and race, and the genetic relationships were delineated using 13 microsatellite markers. All isolates except one from potato were V. dahliae, with 55.1 and 12.1% race 1, and 43.6 and 83.1% race 2 in olive and potato, respectively. The genetic structure of the studied population was best described by two large and two small clusters. Membership in the two large clusters was determined by the presence or absence of the effector gene Ave1. Furthermore, genetic structure was moderately associated with the host of origin but was weakly associated with the geographic origin. All but four isolates represented by three multilocus haploid genotypes were MAT1-2. This study identified a clear lack of gene flow between virulence genotypes of V. dahliae despite the proximity of these cropping systems and the wide distribution of genetic diversity among hosts and geographic regions in Lebanon.

Control of leopard Zeuzera pyrina (L.) (Lepidoptera: Cossidae), by imidaclorprid in olive Trees.

Olive tree is subjected to attack by many insect pest species that effect on the yield quality and quantity. Among the most common pest species surveyed in Egypt is; the leopard Zeuzera pyrina (L.) (Lepidoptera: Cossidae), which considered a serious pest in olive fields causing a lot of damage and loss in olive trees. Imidacloprid is one of the natural insecticide cause the infestations decrease of many insect pests. The effect of Imidacloprid was tested under laboratory and field conditions against Z. pyrina. Results showed that the LC50 of Imidacloprid recoded 120 ppm when Z. pyrina treated with different concentrations. When the nano imidaclorprid applied on the target pests the LC50 recorded 47 ppm. Under field conditions, the infestations were significantly decreased to 23±8.9 and13±2.1 individuals after treated with Imidacloprid in Ebn Malek and Ismailia, respectively. In the same last places the nano Imidacloprid application showed a significant decrease in the pests infestations reached to 15±5.1 and 6±6.6 larvae as compared to 95±1.9 and 96±3.4 larvae in the control. The yields weights in both two regions were significantly increased as the result of nano imidacloprid applications.

Mound measurements — quantifying medium-term soil erosion under olive trees in Northern Jordan

Over the last few decades many quantitative erosion studies have revealed that olive orchard expansion and increased mechanization in southern European countries have led to increased soil erosion under olive trees. Consequently, these studies have suggested different methods of mitigation. In light of the 2014 European trading zone expansion to countries east and south of the Mediterranean, a further intensification of olive plantations is postulated to meet market demands. To attain first medium-term estimates of erosion in Northern Jordan and its driving factors, a new method measuring olive mounds was implemented. Seven fields with clearly erosive structures were chosen throughout the Wadi Al-Arab catchment in Northern Jordan. Topographic measurements were used to reconstruct the historical and recent surface level and calculate the volume eroded since the planting of the trees. A total of 81 bulk density measurements and 14 tree cores allowed the estimation of the soil loss in tons per hectare. The combination of modified land use map and slope information helped to identify similar olive fields with high erosive potential.Results show that the method provides medium-term quantitative estimates for averaged soil loss consistent with some existing results from similar research areas in the Mediterranean. They clearly indicate the significant potential for erosion in olive orchards with around 95±8tha−1yr−1. Tillage practice and water erosion were identified as critical erosion processes, both depending on tillage characteristics, tillage timing, and soil parent material. The investigated fields represent about 19% of the catchment's surface area and are likely to contribute to the measured yearly sediment yield that fills up the Wadi Al-Arab reservoir with sediments.

Dose and frequency dependent effects of olive mill wastewater treatment on the chemical and microbial properties of soil

Olive mill wastewater (OMW) is a problematic by-product of olive oil production. While its high organic load and polyphenol concentrations are associated with troublesome environmental effects, its rich mineral and organic matter contents represent valuable nutrients. This study aimed to investigate the valorization of this waste biomass as a potential soil conditioner and fertilizer in agriculture. OMW was assayed at three doses 50, 100, and 200m3ha−1year−1) over three successive years in olive fields. The effects of the effluent on the physico-chemical and microbial properties of soil-layers were assessed. The findings revealed that the pH of the soil decreased but electrical conductivity and organic matter, total nitrogen, sodium, and potassium soil contents increased in proportion with OMW concentration and frequency of application. While no variations were observed in phosphorus content, slow increases were recorded in calcium and magnesium soil contents. Compared to their control soil counterparts, aerobic bacteria and fungi increased in proportion with OMW spreading rates. The models expressing the correlation between progress parameters and OMW doses were fitted into a second degree polynomial model. Principal component analysis showed a strong correlation between soil mineral elements and microorganisms. These parameters were not related to phosphorus and pH.

Aerodynamic Parameterization of the Satellite-Based Energy Balance (METRIC) Model for ET Estimation in Rainfed Olive Orchards of Andalusia, Spain

Sensitivity of estimates of evapotranspiration (ET) for olive fields located in Andalusia (Spain) to aerodynamic parameterization in METRIC (Mapping EvapoTranspiration with high Resolution and Internalized Calibration) was evaluated to better understand behavior of the model and spatial and temporal distribution of ET from olives, with the ultimate aim of designing customized irrigation schedules. Previous METRIC analyses have primarily focused on the estimation of ET over fields of annual crops, with few applications to complex canopies such as olive. The model was compared against FAO 56-soil water balance-based ET estimations for non-irrigated olive fields. In the first comparisons METRIC model used a general equation for momentum roughness length (zom) based on a fixed function of height estimated from LAI (Leaf Area Index) that underestimated the olives height and therefore zom, so that ET derived as a residual of the energy balance was overestimated (RMSE = 1.12 mm/day) compared to the soil water balance derived ET. The Perrier roughness function based on LAI and tree canopy architecture for sparse trees, coupled with improved olive height estimates (employing tree density and canopy shape factors) improved estimates for zom. This approach produced closer comparisons to rainfall-constrained ET estimates based on soil water balance for rainfed olive orchards (RMSE = 0.25 mm/day). This study does not attempt to validate METRIC results; instead utilizes a comparative approach between two independent methodologies to improve olive ET estimation via remote sensing, with the strong advantage, over the soil water balance approach, of improved spatial resolution over large areas.

Object-based classification of remotely sensed olive tree fields, using mathematical morphology

Object-based classification of remotely sensed olive tree fields, using mathematical morphology

Same Land Cover, Same Land Use at the Large Scale, Different Landscapes at the Small Scale: Landscape Change in Olive Plantations on Lesvos Island, Greece

In this paper, agricultural landscape change at the small scale (for example, at the farm and field level) is studied to conceptualize the processes that change these landscapes (such as features, forms and functions) according to the decisions that farmers make. The case study is olive plantations on the island of Lesvos, Greece. The five-year differences in land cover, land use and landscape at the small scale of a number of olive fields in the same area are studied in three dimensions: symbolic, productive and ecological, with data that come from the observation of practices and vegetation measurements. A conceptual framework is constructed that links the changes of six different landscapes at the individual olive field level with specific management choices of farmers. Findings demonstrate that although olive plantations are of the same land cover and land use class as at the large scale, diverging practices create different landscapes at the small scale along a continuous line with many intermediate cases. The findings also demonstrate that the whole system is dynamic, with the different small-scale landscapes changing into each other continuously due to different practices. Understanding this dynamic diversity requires studying human interventions at the right scale, the one that corresponds to the scale of the changes at the farm.

Comparison of two methods for quantification of tillage erosion rates in olive orchards of north-west Syria

The hilly area of north-western Syria is characterised by olive cultivation on hill slopes. Most of the sloping olive fields are frequently ploughed by a local, donkey-drawn tillage implement ( fadhan), which potentially results in tillage erosion. The aim of this study was to compare different methods for the assessment of tillage erosion rates in sloping olive fields. Two basic approaches for the assessment of tillage erosion can be used; either marking the soil matrix, or using aggregate-sized tracers. These two approaches were applied and compared in olive fields to determine a relation between slope and average soil displacement. Aluminium cubes were used to represent the coarse fraction (CFT) and a sodium chloride solution was used to measure the movement of the fine fraction (FFM). The field experiments included 35 strip plots containing 40 aluminium tracers, on 18 different slopes ranging from 2 to 43% and 15 strip plots marked with 10 l of aqueous sodium chloride solution on the same slopes. Two working directions, up–down and along the contour, were analysed and compared. After tilling the plots, the positions of the aluminium tracers were recorded and samples were taken from the FFM plots. FFM redistribution was determined by measuring electrical conductivity of extract solutions. A statistical analysis revealed that there were no significant differences between the two methods. Soil loss and accumulation were calculated for one of the trial sites. Maximum soil loss values for contour tillage, were almost nine times less than for up and down tillage.