Intensive Olive Orchards Research Articles

Cultivar ideotype for intensive olive orchards: plant vigor, biomass partitioning, tree architecture and fruiting characteristics

In order to achieve higher and earlier yield, modern olive orchards are increasingly intensified, with tree densities up to > 1500 trees hectare-1. With increasing tree densities, individual-tree canopy volume must be proportionally reduced. Not all cultivars are adaptable to high and very high orchard densities, because of excessive vigor and/or insufficient bearing when the canopy is pruned to a small volume. However, what makes an olive cultivar suitable for intensive and super intensive orchards is not clear. Recently, few studies have addressed this topic, suggesting that tree architecture and early bearing are essential traits. Yet, what architectural and productive features are important, how they work and whether they are interrelated remains elusive. This review summarizes and interprets the literature on olive, as well as the more abundant literature available for other fruit species, aiming to provide a comprehensive knowledge framework for understanding how tree architectural characteristics, plant vigor, and fruiting vary across olive genotypes, and how they are interconnected. It is concluded that, among the architectural characteristics, greater branching and smaller diameters of woody structures are particularly important features for cultivar suitability to intensive and super intensive olive orchards. Greater branching allows to produce more fruiting sites in the small volume of canopy allowed in these systems. It also reduces investments in woody structures, liberating resources for fruiting. Additional resources are liberated with smaller structure diameters. Greater branching also increases resources by increasing biomass partitioning into leaves (i.e. the photosynthetic organs), relative to wood. Since yield is affected by the competition for resources with vegetative growth, reducing resource investments in woody structures and/or increasing resource directly, increases yield. Yield, in turn, depresses vegetative growth, reducing vigor and the need for pruning. High yields also produce short shoots which have relatively greater investments in leaf mass and area, and lower in the woody stem, making them more suitable than long shoots to support concurrent fruit growth. This single framework of interpretation of how the different architectural and fruiting characteristics work and interact with one-another, will provide guidance for cultivar selection and breeding for intensive and super intensive olive orchards.

Assessment of Spray Deposit and Loss in Traditional and Intensive Olive Orchards with Conventional and Crop-Adapted Sprayers

Plant protection product (PPP) applications to isolated olive trees are commonly performed with regular air-assisted sprayers, which are not adapted to their particular characteristics. Whilst strong efforts have been undertaken over the last years to improve technical aspects like canopy detection and automated proportional dosing, nearly no efforts have been made regarding the sprayer adaption to the crop. For this reason, three prototype sprayers were developed for traditional and intensive olive cultivations systems (P1: centrifugal fan; P2: six small side axial fans; P3: two axial fans in tower structure) with the purpose to improve the application efficiency. The main goal of the present study was to check spray quality and efficiency in comparison with the conventional sprayer in both cultivation systems. The sprayers were tested in two different olive groves and properly calibrated according to the tree dimensions. The spray deposition, coverage, drift, and losses to the ground were measured in five trees per cultivation system by placing the appropriate collectors. The sprayers performed very differently in both cultivation systems. In the intensive system, the spray deposition did not present significant differences (p = 0.105). However, it did in the traditional system (p = 0.003), with P3 obtaining the best results. The spray coverage followed the same trend, with significant differences only in the traditional orchard (p = 0.011), with the prototypes leading. The conventional equipment generated the highest spray losses in both cultivation systems. Crop adapted spraying can significantly improve the spray quality and efficiency in difficult crops like olive. This topic may have a key importance to match the environmentally sustainable use of PPP.

Effect of macronutrient fertilization on olive oil composition and quality under irrigated, intensive cultivation management.

Intensive olive (Olea europaea L.) orchards are fertilized, mostly with the macronutrients nitrogen (N), phosphorus (P) and potassium (K). The effects of different application levels of these nutrients on olive oil composition and quality were studied over 6 years in a commercial intensively cultivated 'Barnea' olive orchard in Israel. Oil quality and composition were affected by N, but not P or K availability. Elevated N levels increased free fatty acid content and reduced polyphenol level in the oil. Peroxide value was not affected by N, P or K levels. The relative concentrations of palmitoleic, linoleic and linolenic fatty acids increased with increasing levels of N application, whereas that of oleic acid, monounsaturated-to-polyunsaturated fatty acid ratio and oleic-to-linoleic ratio decreased. These results indicate that intensive olive orchard fertilization should be carried out carefully, especially where N application is concerned, to avoid a decrease in oil quality due to over-fertilization. Informed application of macronutrients requires leaf and fruit analyses to establish good agricultural practices, especially in view of the expansion of olive cultivation to new agricultural regions and soils. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Long-Term Impact of Phosphorous Fertilization on Yield and Alternate Bearing in Intensive Irrigated Olive Cultivation.

Phosphorus (P) availability significantly impacts olive tree reproductive development and consequential fruit production. However, the importance of P fertilization in olive cultivation is not clear, and P application is usually recommended only after P deficiency is identified. In order to determine the long-term impacts of continuous P fertilization in intensive irrigated olive cultivation, the growth and production of trees in an intensive orchard with or without P fertilization were evaluated over six consecutive seasons. Withholding of P resulted in significant reduction in soil P quantity and availability. Under lower P availability, long-term fruit production was significantly impaired due to reduced flowering and fruit set. In addition, trees under conditions of low P were characterized by higher alternate bearing fluctuations. Olive tree vegetative growth was hardly affected by P fertilizer level. The impairment of tree productivity was evident in spite of the fact that leaf P content in the treatment without P fertilization did not decrease below commonly reported and accepted thresholds for P deficiency. This implies that the leaf P content sufficiency threshold for intensive olive orchards should be reconsidered. The results demonstrate the negative impact of insufficient P fertilization and signify the need for routine P fertilization in intensive olive cultivation.

Pseudomonas palmensis sp. nov., a Novel Bacterium Isolated From Nicotiana glauca Microbiome: Draft Genome Analysis and Biological Potential for Agriculture.

A novel Pseudomonas, designated strain BBB001T, an aerobic, rod-shaped bacterium, was isolated from the rhizosphere of Nicotiana glauca in Las Palmas Gran Canaria, Spain. Genomic analysis revealed that it could not be assigned to any known species of Pseudomonas, so the name Pseudomonas palmensis sp. nov. was proposed. A 16S rRNA gene phylogenetic analysis suggested affiliation to the Pseudomonas brassicae group, being P. brassicae MAFF212427 T the closest related type strain. Upon genomic comparisons of both strains, all values were below thresholds established for differentiation: average nucleotide identity (ANI, 88.29%), average amino acid identity (AAI, 84.53%), digital DNA-DNA hybridization (dDDH, 35.4%), and TETRA values (0.98). When comparing complete genomes, a total of 96 genes present exclusively in BBB001T were identified, 80 of which appear associated with specific subsystems. Phenotypic analysis has shown its ability to assimilate glucose, potassium gluconate, capric acid malate, trisodium citrate, and phenylacetic acid; it was oxidase positive. It is able to produce auxins and siderophores in vitro; its metabolic profile based on BIOLOG Eco has shown a high catabolic capacity. The major fatty acids accounting for 81.17% of the total fatty acids were as follows: C16:0 (33.29%), summed feature 3 (22.80%) comprising C16:1 ω7c and C16:1 ω6c, summed feature 8 (13.66%) comprising C18:1 ω7c, and C18:1ω6c and C17:0 cyclo (11.42%). The ability of this strain to improve plant fitness was tested on tomato and olive trees, demonstrating a great potential for agriculture as it is able to trigger herbaceous and woody species. First, it was able to improve iron nutrition and growth on iron-starved tomatoes, demonstrating its nutrient mobilization capacity; this effect is related to its unique genes related to iron metabolism. Second, it increased olive and oil yield up to 30% on intensive olive orchards under water-limiting conditions, demonstrating its capacity to improve adaptation to adverse conditions. Results from genomic analysis together with differences in phenotypic features and chemotaxonomic analysis support the proposal of strain BBB001T (=LMG 31775T = NCTC 14418T) as the type strain of a novel species for which the name P. palmensis sp. nov is proposed.

Canopy Index Evaluation for Precision Management in an Intensive Olive Orchard

The evaluation of the canopy in orchard cultivation is a key aspect for the main cultivation techniques, such as pruning, thinning, harvesting, production and improved fruit quality. The possibility of having a periodic screening of the state of development of the vegetation can be of practical support to growers. Research on the application of precision agriculture has provided tools for reading and interpreting crops, and the resulting information is potentially useful. Many of the systems under study provide after monitoring information processing systems that reduce the timeliness of intervention. Especially in intensive systems such as olive groves, knowing the precise intervention points is often essential. In the present work, a multi-parameter instrument was used for field monitoring on the agricultural tractor to analyse the canopy. The system allows measuring various indicators such as height and density of the canopy and the temperature and humidity of the ambient air and at the leaf level. The first evaluation of the data made it possible to identify areas with greater vegetative concentration and greater or lesser development. The system made it possible to identify with good approximation the homogeneous areas, based on the Canopy Index (CI) evaluation to be subjected to subsequent and specific management efforts, dividing them into low, ordinary, and high vegetative growth. The results highlight the possibility of directly combining operators able to intervene with the same passage, selecting based on differences in growth, typical varietal specificities, and areas of deficient development or that are affected by plant diseases, confirming the objective of defining the areas of the orchard that require different management and workload techniques.

Identification of olive fruit, in intensive olive orchards, by means of its morphological structure using convolutional neural networks

Accurate yield estimation is a greatly desired objective in oliviculture due to the high economic value of its production. This paper presents a methodology aimed at achieving that end. It comprises an artificial-vision algorithm able to detect visible olives in digital images of olive trees captured directly in the field, at night-time and with artificial illumination. These images were taken in an intensive olive orchard of the Picual Olea europaea L. variety in September 2018 (two months prior to harvesting). Regarding the methodology, first, the images are pre-processed to generate a set of sub-images with high probability of containing an olive, thus reducing the search space by a magnitude of 103. Next, these sub-images are classified by a convolutional neural network (CNN) as olive, if they are centred in an olive fruit, or as other in any other case (even if they contain peripheral fruits). To train and validate the CNN, a special database called OLIVEnet was compiled with two disjoint sets integrating these sub-images. A training and a validation set was built with 234,168 and 299,946 olive and other sub-images, respectively. Five different CNN topologies were tested, correctly classifying the best performing one in 83.13% of olive instances, with a precision of 84.80%, and 99.12% of other instances; measured accuracy and F1 Score were 0.9822 and 0.8396, respectively. As far as the authors' knowledge goes, this article presents the first image analysis approach to automatically identify olive fruits in an image of the entire tree directly taken in the field. The obtained results constitute a first and solid step towards the implementation of an automatic system for yield estimation of olive orchards.

Evapotranspiration partition using the multiple energy balance version of the ISBA-A-g<sub>s</sub> land surface model over two irrigated crops in a semi-arid Mediterranean region (Marrakech, Morocco)

Abstract. The main objective of this work is to question the representation of the energy budget in soil–vegetation–atmosphere transfer (SVAT) models for the prediction of the turbulent fluxes in the case of irrigated crops with a complex structure (row) and under strong transient hydric regimes due to irrigation. To this end, the Interaction between Soil, Biosphere, and Atmosphere (ISBA-A-gs) is evaluated at a complex open olive orchard and, for the purposes of comparison, on a winter wheat field taken as an example of a homogeneous canopy. The initial version of ISBA-A-gs, based on a composite energy budget (hereafter ISBA-1P for one patch), is compared to the new multiple energy balance (MEB) version of ISBA that represents a double source arising from the vegetation located above the soil layer. In addition, a patch representation corresponding to two adjacent, uncoupled source schemes (hereafter ISBA-2P for two patches) is also considered for the olive orchard. Continuous observations of evapotranspiration (ET), with an eddy covariance system and plant transpiration (Tr) with sap flow and isotopic methods were used to evaluate the three representations. A preliminary sensitivity analyses showed a strong sensitivity to the parameters related to turbulence in the canopy introduced in the new ISBA–MEB version. For wheat, the ability of the single- and dual-source configuration to reproduce the composite soil–vegetation heat fluxes was very similar; the root mean square error (RMSE) differences between ISBA-1P, ISBA-2P and ISBA–MEB did not exceed 10 W m−2 for the latent heat flux. These results showed that a composite energy balance in homogeneous covers is sufficient to reproduce the total convective fluxes. The two configurations are also fairly close to the isotopic observations of transpiration in spite of a light underestimation (overestimation) of ISBA-1P (ISBA–MEB). At the olive orchard, contrasting results are obtained. The dual-source configurations, including both the uncoupled (ISBA-2P) and the coupled (ISBA–MEB) representations, outperformed the single-source version (ISBA-1P), with slightly better results for ISBA–MEB in predicting both total heat fluxes and evapotranspiration partition. Concerning plant transpiration in particular, the coupled approach ISBA–MEB provides better results than ISBA-1P and, to a lesser extent, ISBA-2P with RMSEs of 1.60, 0.90, and 0.70 mm d−1 and R2 of 0.43, 0.69, and 0.70 for ISBA-1P, ISBA-2P and ISBA–MEB, respectively. In addition, it is shown that the acceptable predictions of composite convective fluxes by ISBA-2P for the olive orchard are obtained for the wrong reasons as neither of the two patches is in agreement with the observations because of a bad spatial distribution of the roots and a lack of incoming radiation screening for the bare soil patch. This work shows that composite convection fluxes predicted by the SURFace EXternalisée (SURFEX) platform and the partition of evapotranspiration in a highly transient regime due to irrigation is improved for moderately open tree canopies by the new coupled dual-source ISBA–MEB model. It also points out the need for further local-scale evaluations on different crops of various geometry (more open rainfed agriculture or a denser, intensive olive orchard) to provide adequate parameterisation to global database, such as ECOCLIMAP-II, in the view of a global application of the ISBA–MEB model.

Automated Identification of Crop Tree Crowns from UAV Multispectral Imagery by Means of Morphological Image Analysis

Within the context of precision agriculture, goods insurance, public subsidies, fire damage assessment, etc., accurate knowledge about the plant population in crops represents valuable information. In this regard, the use of Unmanned Aerial Vehicles (UAVs) has proliferated as an alternative to traditional plant counting methods, which are laborious, time demanding and prone to human error. Hence, a methodology for the automated detection, geolocation and counting of crop trees in intensive cultivation orchards from high resolution multispectral images, acquired by UAV-based aerial imaging, is proposed. After image acquisition, the captures are processed by means of photogrammetry to yield a 3D point cloud-based representation of the study plot. To exploit the elevation information contained in it and eventually identify the plants, the cloud is deterministically interpolated, and subsequently transformed into a greyscale image. This image is processed, by using mathematical morphology techniques, in such a way that the absolute height of the trees with respect to their local surroundings is exploited to segment the tree pixel-regions, by global statistical thresholding binarization. This approach makes the segmentation process robust against surfaces with elevation variations of any magnitude, or to possible distracting artefacts with heights lower than expected. Finally, the segmented image is analysed by means of an ad-hoc moment representation-based algorithm to estimate the location of the trees. The methodology was tested in an intensive olive orchard of 17.5 ha, with a population of 3919 trees. Because of the plot’s plant density and tree spacing pattern, typical of intensive plantations, many occurrences of intra-row tree aggregations were observed, increasing the complexity of the scenario under study. Notwithstanding, it was achieved a precision of 99.92%, a sensibility of 99.67% and an F-score of 99.75%, thus correctly identifying and geolocating 3906 plants. The generated 3D point cloud reported root-mean square errors (RMSE) in the X, Y and Z directions of 0.73 m, 0.39 m and 1.20 m, respectively. These results support the viability and robustness of this methodology as a phenotyping solution for the automated plant counting and geolocation in olive orchards.

Measuring and Modelling Soil Evaporation in an Irrigated Olive Orchard to Improve Water Management

The aim of this study was to estimate soil evaporation (Es) in an intensive olive orchard. Measurements of Es were performed for 19 days using microlysimeters, during summers 2010, 2011 and 2012 in southeast Portugal. In order to relate each area type to radiation transmissivity, ground cover measurements were performed over the years. These data were used to calibrate and validate an empirical model for Es estimation. Measured daily average Es was 0.55 ± 0.14 mm; the model estimated 0.53 ± 0.18 mm for the same days, with a determination coefficient of 0.94. This corresponds to 9% of the reference evapotranspiration, representing well the overall values estimated for the summer, except for days after rain. Regarding the wet area, measured Es for the validation data set was 2.42 L/(m2 of wet area), the estimated was 2.49 L/(m2 of wet area). Measured average Es in dry area (validation data set) was 0.42 L/(m2 of dry area), estimated Es was 0.43 L/(m2 of dry area). The large exposed dry area had a significant contribution to evaporation. On average, estimated Es during a typical Mediterranean summer was 10% of reference evapotranspiration, representing 30% of transpiration and 23% of evapotranspiration.

Crop Coefficients and Transpiration of a Super Intensive Arbequina Olive Orchard using the Dual Kc Approach and the Kcb Computation with the Fraction of Ground Cover and Height

The SIMDualKc model was used to simulate crop water requirements for a super high density olive orchard in the region of Alentejo, Portugal. This model uses the dual crop coefficient approach to estimate and partitioning the actual crop evapotranspiration (ETc act) and therefore to perform the soil water balance. The model was calibrated with 2011 tree transpiration using trunk sap flow measurements and was validated using similar data from 2012 and tested with 2013 data. Low root mean square errors (RMSE < 0.53 mm·d−1) and acceptable modelling efficiency indicators (EF > 0.25) were obtained. Further validation was performed comparing modelled ETc act with eddy covariance measurements. These indicators support the appropriateness of using SIMDualKc to guide irrigation management. The basal crop coefficient (Kcb) curves obtained with SIMDualKc for those 3 years were compared with the Kcb values computed with the Allen and Pereira approach (A&P approach) where Kcb is estimated from the fraction of ground cover and plant height considering an adjustment factor for crop stomatal control (Fr). Fr values were obtained through a trial and error procedure through comparing the Kcb estimated with this approach and with SIMDualKc. The Kcb curves obtained by both methods resulted highly correlated, which indicates that the A&P approach may be used in the irrigation management practice to estimate crop water requirements. Results of performing the soil water balance with SIMDualKc have shown that soil evaporation is a large fraction of ETc act, varying between 41% and 45% for the 3 years under study. Irrigation, applied with a drip system, represented 39 to 56% of ETc act, which shows the great importance of irrigation to achieve the water requirements of super intensive olive orchards. Nevertheless, the analysis has shown that the irrigation management adopted at the orchard produces a water deficit larger than desirable, with a ratio of ETc act to non-stressed crop evapotranspiration (ETc) varying from 70% to 94% during the mid-season, when that ratio for a eustress irrigation management could be around 90%.

Potential nutritional value of olive-mill wastewater applied to irrigated olive (Olea europaea L.) orchard in a semi-arid environment over 5 years

Abstract Controlled spreading of olive mill wastewater (OMW) on cultivated soils is a low-cost disposal method of an otherwise problematic pollutant, with potential recycling of plant nutrients. The nutritional value of successive OMW applications was examined in an intensive olive orchard grown on sandy loam soil in a semi-arid region. Application at 50–150 m3 ha−1 y−1 for 5 years had no negative effects on tree vegetative growth, fruit yield or oil quality. OMW application did not increase N content in the soil or plants; yet, it caused a consistent increase in soil P and K contents and significantly affected diagnostic leaf P and K concentrations. It also led to a significant increase in exchangeable potassium percentage (EPP) already from the first application, and soluble K migration to deep soil layers after 3 years of successive applications. Soil tillage after OMW application did not affect N, P or K dynamics in the soil or uptake of these nutrients by plants. Controlled application of OMW to intensive olive orchards can be a significant source of K and P and thus save on fertilizers without negatively affecting tree performance.

Assessing Olive Evapotranspiration Partitioning from Soil Water Balance and Radiometric Soil and Canopy Temperatures

Evapotranspiration (ETc) partitioning and obtaining of FAO56 dual crop coefficient (Kc) for olive was carried out with the SIMDualKc software application for root zone and topsoil soil water balance based on the dual crop coefficients. A simplified two source-energy balance model (STSEB), based on daily remotely sensed soil and canopy thermal infrared data and retrieval of surface fluxes, also provided information on partitioning ETc for the olive orchard. Both models were calibrated and validated with ground-based, sap flow-derived transpiration rates, and their performance was compared in partitioning ETc for incomplete cover, intensive olive grown in orchards (≤300 trees ha−1). The SIMDualKc proved adequate in partitioning ETc. The STSEB model underestimated ETc mostly by inadequately simulating soil evaporation and its contribution to the total latent heat flux. Such results suggest difficulties in using information from the STSEB algorithm for assessing ETc and dual Kc crop coefficients of intensive olive orchards with incomplete ground cover.

Mecaolivar outcomes: testing newly developed harvesters in traditional and intensive olive orchards

Mecaolivar outcomes: testing newly developed harvesters in traditional and intensive olive orchards

Three years of monitoring evapotranspiration components and crop and stress coefficients in a deficit irrigated intensive olive orchard

A long-term experiment was conducted to study water use of olive trees in a six-year-old, deficit irrigated, intensive olive orchard (‘Arbequina’) in one of the driest regions of Southern Portugal. Woody agricultural crops are regularly cultivated with some water stress to maintain an equilibrium between the vegetative and reproductive cycles, to improve production quality and, when irrigated, to save water. To achieve a precise irrigation scheduling it is necessary to quantify water use reduction due to water stress. This study reports results from spring 2010 to autumn 2012, and encompasses a hydrological drought occurred in 2012. A long-term seasonal time series of transpiration (Tr), was obtained by combining data on evapotranspiration (ET) measured with the eddy covariance method, soil evaporation measured with microlysimeters and sap flow measured with a heat dissipation method. For the years 2010 and 2011, with normal precipitation, Tr varied between 2 and 4mm/day, in the summer. In 2012, due to the winter drought, soil water content did not reach field capacity during the wet season and an important reduction in Tr was observed ranging from 1 to 2mm/day during summer. Predawn leaf water potential (Ψpd) was selected as plant water status indicator, because these olive trees showed near-isohydric behaviour. A function relating Ψpd to the correspondent stress coefficient (Ks) was used to decompose Tr/ETo into the basal crop coefficient (Kcb) and the Ks. The first, during the summer period, oscillated around 0.4 for years with precipitation close to average, while Ks estimated from Ψpd decreased between 1.0 in early June to about 0.83 before first autumn rain. However, these Ks values did not explain the important reduction observed in Tr during the 2012 severe drought. Measured Kcb values were compared to the ones modelled using approaches based on density factor. The derived Kcb values for summer were lower than those observed.

Mechanical vibration transmission and harvesting effectiveness is affected by the presence of branch suckers in olive trees

Trunk shakers are among the most widespread machines for mechanical harvesting in intensive olive orchards (300–500 trees ha−1). Harvesting effectiveness is an important issue for this sort of machine because, due to the heterogeneity of the tree canopy structure, vibration transmission is uneven and some branches vibrate poorly. The aim of the present work was to determine if the removal of internal suckers before harvesting could improve vibration transmission and harvesting effectiveness. ‘Leccino’ and ‘Frantoio’ trees trained to free vase and planted in an intensive olive orchard (400 trees ha−1) were used in experiments carried out in 2012 and 2013 in two different orchards. Triaxial accelerometers, placed on tree trunk and on the main branches, were used to measure vibration transmitted to the canopy by two custom-built orbital and multidirectional trunk shakers. On average, harvesting effectiveness increased significantly from 83.4% to 95.6% as a consequence of sucker removal. Maximum acceleration transmitted to the trunk and branches increased by 33.1% and 46.6% respectively after internal sucker removal. These results suggest that internal suckers reduce vibration transmission through the canopy, affecting harvesting effectiveness. Furthermore, the larger the fruit retention force per fruit mass was, the larger was the effect of sucker removal on harvesting effectiveness. These results suggests that sucker removal prior to harvesting is advisable to improve harvesting effectiveness in open vase trees harvested by trunk shakers, in particular when mechanical harvesting is carried out at an early stage of fruit ripening.

Evapotranspiration measured in a traditional rainfed and an irrigated intensive olive orchard during a year of hydrological drought

Evapotranspiration measured in a traditional rainfed and an irrigated intensive olive orchard during a year of hydrological drought

Improving plant protection product applications in traditional and intensive olive orchards through the development of new prototype air-assisted sprayers

Because of the pollution caused by inappropriate pesticide applications to olive canopies, the Mecaolivar pre-commercial procurement project was undertaken to develop new airblast sprayers to optimise application efficiency and overcome the limitations of conventional sprayers used in traditional and intensive orchards. Three prototype sprayers were developed, evaluated, and calibrated under laboratory conditions and were tested in the field by spraying trees in traditional and intensive cultivation systems. Water-sensitive paper was used to assess the spray coverage achieved. The prototype sprayers were designed to adapt the deposition nozzle positions to the canopy shape to reduce spray drift and off-target application. The first prototype (P1) consisted of a sprayer with a centrifugal fan and adaptable individual spouts, the second (P2) consisted of a sprayer with six small hydraulically-driven axial fans mounted on two mobile structures, and the third (P3) consisted of two axial fans mounted on a tower-like structure with mobile air outlets. The results of the field test showed that the prototypes could be more efficient than conventional equipment. In applying the same liquid volume, the P2 and P3 prototypes increased the coverage by 61% and 46% on average in intensive and traditional systems, respectively, compared to a commercial airblast sprayer, without a significant decrease in the deposit homogeneity throughout the crown.

Mobile terrestrial laser scanner applications in precision fruticulture/horticulture and tools to extract information from canopy point clouds

LiDAR sensors are widely used in many areas and, in recent years, that includes agricultural tasks. In this work, a self-developed mobile terrestrial laser scanner based on a 2D light detection and ranging (LiDAR) sensor was used to scan an intensive olive orchard, and different algorithms were developed to estimate canopy volume. Canopy volume estimations derived from LiDAR sensor readings were compared to conventional estimations used in fruticulture/horticulture research and the results prove that they are equivalent with coefficients of correlation ranging from r = 0.56 to r = 0.82 depending on the algorithms used. Additionally, tools related to analysis of point cloud data from the LiDAR-based system are proposed to extract further geometrical and structural information from tree row crop canopies to be offered to farmers and technical advisors as digital raster maps. Having high spatial resolution information on canopy geometry (i.e., height, width and volume) and on canopy structure (i.e., light penetrability, leafiness and porosity) may result in better orchard management decisions. Easily obtainable, reliable information on canopy geometry and structure may favour the development of decision support systems either for irrigation, fertilization or canopy management, as well as for variable rate application of agricultural inputs in the framework of precision fruticulture/horticulture.

Assessing the optimal liquid volume to be sprayed on isolated olive trees according to their canopy volumes

The application of pesticides to traditional and intensive olive orchards in Southern Spain has led to environmental problems. More specifically, the lack of an accurate, useful criterion to regulate the spray volume in relation to canopy characteristics has led to spray drift and runoff, which are threats to local ecosystems. The aim of this study was to determine the optimal relationship between canopy volume and the spray application volume, called specific spray volume, CV, through laboratory and field trials.In the laboratory trial, 6 specific spray volumes (0.05, 0.08, 0.10, 0.12, 0.15, and 0.20Lm−3) were tested in a specially designed structure containing small, live olive trees in order to simulate an intensive plantation system. The model aimed to evaluate the coverage of pesticide application on water sensitive paper (WSP) collectors. In the field trial, the three laboratory specific spray volumes that gave the best coverage values were tested on live, intensively managed trees, whose crown volume was manually measured. Food dye E-102 was used to determine the spray deposition on artificial targets (10×10cm absorbent paper pieces), and WSP was used to evaluate spray coverage. The spray penetration and deposit homogeneity inside the canopy were also evaluated. Weather conditions during the field trial were monitored with a weather station.The results of the laboratory trial showed that the three best specific spray volumes were 0.08, 0.10, and 0.12Lm−3, resulting in mean coverage values of approximately 30%. The ANOVA of the field trial results showed that the 0.12Lm−3 was the optimal specific spray volume for isolated olive trees. This specific spray volume gave the highest mean deposits, the best efficiency (as measured by the greatest normalized deposit), the most favourable penetration and homogeneity, and the highest coverage values.