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Comunicação apresentada no VII Symposium of Temperate Zone Fruits in the Tropics and Subtropics, que decorreu de 21 a 25 de Outubro em Florianópolis, Brasil. Foi organizado pela International Society of Horticultural Science.

The effect of different levels of nitrogen fertilisation on the susceptibility to peach constriction canker, caused by Phompsis amygdali, was studied in two potted experiments, established in April 2003 and February 2005. The `Sprincrest’ cultivar was used because of its medium susceptibility. Four different nitrogen levels were used: N0 — without nitrogen, N1 — insufficient level, N2 — level considered sufficient, and N3 — excessive level. Plant inoculations with P. amygdali were carried out in November. The canker area around the inoculation sites was measured between January and March of the following year and used as susceptibility assessment. In 2003, the average canker size was much higher than in 2005, which probably shows the effects of temperature and precipitation on canker size. The results show that there is an effect of nitrogen fertilisation on plant vigour and therefore on constriction canker susceptibility. Both N0 and N3 increased the canker area.

In this work, the "yield potential" is proposed as a new methodology to relate production with quality, which allows us to achieve the optimal bearing status of the tree for each orchard and season. The "yield potential" is defined as the maximum production that can be obtained in each orchard ecosystem as a function of a commercial and qualitative target such as fruit size or sugar content. The presented methodology is based on the differentiation of the bearing status of the trees by hand thinning, and grouping them, after harvest, according to the number of fruits per tree for nonlinear regression analysis. Estimating thinning needs or effectiveness to obtain the desired commercial fruit size and relating average fruit weight per tree with commercial fruit size are the most important achievements of this methodology.

Comunicação apresentada no 28th International Horticultural Congress, que decorreu em Lisboa de 22 a 27 de Agosto de 2010.

Peach is a highly perishable climacteric fruit. Cold storage is the most widely used method for peach storage, delaying fruit deterioration. This study describes the experimental tests developed to evaluate the evolution of peach characteristics under different storage conditions of controlled (CA) and normal atmosphere (NA) of ‘Sweet Henry’ cultivar. Tests were performed in refrigeration chambers in industrial and laboratory facilities, throughout 2years. In the controlled atmosphere chamber, the tests were performed with 3different concentrations of O2 and CO2, namely 3 treatments of controlled atmosphere (2% O2-5% CO2, 2% O2-10%CO2and 2% O2-15% CO2), 2treatments of normal atmosphere (at Research Centre and at FarmersOrganization facilities). From each treatment, peach samples were extracted and analyzed at 14, 21, 28, 35 (for all treatments) and at 42, 49, and 56 days(for controlled atmosphere). The analysis of the biometric parameters NDASHsize, weight, color, firmness, total soluble solids, acidity – were performed inorder to evaluate peach quality. In FO treatment, a weight loss of -13% in 2020 and -11% in 2021 was observed after 35 days. In NA treatment the maximum weight loss was -5% after 35 days of storage. A decrease of fruit firmness and acidity content was observed in all the treatments throughout time, but firmness remain globally similar between CA treatments. The CA treatments maintained the fruit quality in terms of weight, and firmness, thus increasing fruit market life. First chilling injury (CI) symptoms were observed at 35 + 2days of storage. The treatment 2% O2-15% CO2 allowed fruit firmness maintenance, the minimal decrease of acidity content and low CI incidence of Sweet Henry cultivar for a storage period of 56 days.

Peach production is an important agricultural activity in the center of Portugal, which is the main region of stone fruit production. This region is characterized by hot and dry summers, that can actively accelerate the organic matter degradation and, thus, increase the susceptibility to erosion and decrease the soil capacity to retain nutrients. To evaluate the relationship of peach production activity and soil characteristics, a long-term project was installed based on 31 peach orchards covering the main peach production area. The main objective was to find out the influence of peach production activity on soil characteristics with special reference on organic matter content. Orchards were monitored since establishment, collecting soil samples at establishment time and after 4 years. Plant development was monitored annually by the evaluation of trunk cross-sectional area and nutrition status by foliar analysis at 100 to 120 days after blooming. Simultaneously, weed development in the row and inter-row was evaluated. Results indicated that peach orchards are very heterogeneous over the first years after planting. After 4 years from the initial 31 orchards, only 23 remained, corresponding to 26% of uprooting orchards, mainly related with Pseudomonas syringae complex incidence. In90% of the orchards the soil content in potassium was classified as high (100-200 mg kg-1; LQARS, 2006) and very high (>200mgkg1; LQARS, 2006). Nevertheless, according to nutritional analysis, the leaf potassium content was classified as low in 35% of the orchards, considering the reference interval of 2to 3% for this nutrient. Nitrogen leaf content was below reference interval in17% of the orchards, and in 22% was above this interval. All orchards use weed cover at inter-rows, mowed regularly. Weeds were controlled in rows using herbicides. Considering the 23 orchards, Organic Matter content increased 0.68% in the row and 0.18% in the interrow, after 4 years.

This paper describes the latest innovations in agricultural robotics, specifically for weed control, harvesting and monitoring, taking into account the challenges of introducing robotics in this sector, such as fruit detection, orchard navigation, task planning algorithms, or sensors optimization. One of the trends in precision agriculture is the introduction of swarm robotics, allowing collaboration between robots. Another trend is in aerial imagery acquisition for ground analysis as well as environmental reconstruction, complemented by field-mounted sensors. Although robots are becoming quite important in the evolution of agriculture, it is still unlikely that all tasks will be automated in the near future due to the complexity arisen by the overall variability of cultures. The analysis of the current state of the art allows the proposal of a robotic rover for multipurpose agricultural activities (R2A2), developed to perform particular and controlled spraying, to pick up fallen fruits and to predict fruit production in peach orchards. These tasks are performed in different period of the campaign, allowing to use of the same robotic platform for different activities. The tasks performed by the robotic platform aim to help increasing productivity, by accurate fruit counting, that allows decision making concerning water requirements and the reduction of herbicide and pesticide applications.The design and construction of this platform aims to be an additional contribution for the rising of agricultural robotics.

The introduction of robotics in certain activities such as fruit harvesting, weed control, monitoring, spraying, soil handling, autonomous navigation, among others, contribute technologically to the sector efficacy and efficiency. The paper presents the design of a robotic gripper for picking up the fallen fruits located at the orchard ground at the end of the season, aiming to contribute for the sustainability of the agricultural processes. The prototype is coupled to a robotic platform's Cartesian manipulator. The technical specifications of the gripper were set through a decision matrix based on a literature review. The gripper was modeled three-dimensionally (3D) using computer-assisted design(CAD), leading to 3D printing model by polylactic acid (PLA) fused deposition modeling (FDM). The control, regulation and command of the gripper are accomplished by an Arduino microcontroller connected to end-switches to limit the work envelope, and to DC motors that carried out the Cartesian manipulation arm and gripper movements. Experimental tests were carried out to evaluate the performance of the gripper in picking fruits, depending on the inclination of the robotic platform and positions of the fruit (central and lateral). The experimental results allow to conclude that the robotic gripper fulfills the objectives for which it was developed.

Introducing robotics in agriculture can allow a rise in productivity and a reduction in costs and waste. Its capabilities can be enhanced to or above the human level, enabling a robot to function as a human does, but with higher precision, repeatability, and with little to no effort. This paper develops a detection algorithm of peach trunks in orchard rows, as autonomous navigation and anti-bump auxiliary system of a terrestrial robotic rover for agricultural applications. The approach involved computational vision, more specifically, the creation of an object detection model based on Convolutional Neural Networks. The framework of the algorithm is Tensorflow, for implementation in a Raspberry Pi 4. The model’s core is the detection system SSD MobileNet 640×640 with transfer learning from the COCO 2017 database. 89 pictures were captured for the database of the model, of which 90% were used for training and the other 10% for testing. The model was converted for mobile applications with a full integer quantization, from 32floatto uint8, and it was compiled for Edge TPU support. The orientation strategy consists of two conditions: a double detection forms a linear function, represented by an imaginary line, which updates every two simultaneous trunks detected. Through the slope of this function and the horizontal deviation of a single detected bounding box from the created line, the algorithm orders the robot to adjust the orientation or keep moving forward. The arithmetic evaluation of the model shows a precision and recall of 94.4%. After the quantization, the new values of these metrics are 92.3 and 66.7%, respectively. These simulation results prove that, statistically, the model can perform the navigation task.

As a result of the increasing world population and the growing demand for food, there is a great need to increase agricultural productivity. However, the problem is aggravated by the population migration from rural areas to cities, which causes a decrease in the workforce in the agricultural sector. In this regard, within the concept of agriculture 4.0, the introduction of autonomous robots in agricultural activities may face these problems, supporting the growing lack of labor and promoting increased agricultural productivity. This work exposes the algorithm used to perform autonomous navigation, based on global positioning systems (GPS), of the robotic rover for agricultural applications (R2A2) multitasking aimed at performing herbicide spraying. An augmented reality (AR) web application has also been developed to assist in the supervision of autonomous vehicles. A code in C/C++ was developed for the autonomous movement of the robotic platform using an Arduino Mega2560 as the main microprocessor and the AR web application based on the positioning which was developed using the AR.JS libraries and the A-FRAME framework compiled in a code HTML. The application was tested in a peach orchard and presented an average of approximately 94% of correct answers, which reveals the accuracy of the technological solution developed. Also exposed are the results and conclusions of the autonomous movement algorithm and the web application.

The concept of Precision Agriculture is usually associated with the usage of high-end technology equipment (hardware or software) to evaluate or monitor the conditions of a determined portion of land, adjusting afterwards the production factors, like seeds, fertilizers, pesticides, growing regulators, water, according to differential detected characteristics. This paper describes an algorithm developed to analyze and process images to recognize fruits, particularly peaches, and calculate it dimensions, like volume and weight. The recognition of peaches on their natural conditions on trees depends on several spatial- and time-variable parameters and requires complex segmentation algorithms. The proposed algorithm applies image segmentation for extraction of characteristics such as color and shape. These characteristics were used to train a classification method through a Support Vector Machine (SVM) to improve the recognition rate of fruits. The algorithm is designed to acquire images with a high-resolution camera installed in a drone that will fly between the tree lines. The production prediction of 29.3 tons per hectare was obtained based on volume and relation weight/volume calculated for the recognized peaches. An overall precision of 72% was achieved for the prediction rate of peaches in orchards (808 trees/ha). This is the first study regarding the application of these concepts under orchard trees aiming the production prediction along the fruit maturation. Other useful future applications are foreseen in orchard trees, related not only to production prediction, for this type of algorithm.

Portuguese growers of “Beira Interior”, an inland region in the centre of Portugal, start harvesting olives only in late November or December and finish in January and sometimes February. Studies on olive ripening carried out in different groves showed that, in general, oil content (% d.w.) stabilises during November and ripening index rises regularly throughout the sampling period. However, there were some differences among cultivars. The results suggest that harvest can begin from mid- -October to the 1st fortnight of November, according to location, for ‘Galega’, in the 1st fortnight of December for ‘Bical’, in the 1st fortnight of November for ‘Carrasquinha‘ and in the 2nd fortnight of November for ‘Cornicabra’, therefore harvest time should begin long before the traditional time.

Beira Baixa olive oil is mainly produced with Galega cv. Galega olive ouil is veryu stable and provides flavour and taste that are traditional for portuguese consumers. Bical and Cordovil de Castelo Branco cvs. are also important in the olive grove of the region. The goal of this study is to understand the role of the composition of the monovariety olive oils (mainly fatty acid composition and total phenol compounds) on the quality of Beira Baixa olive oil. Results for sterols are also shown.

The three main cultivars of Olea europaea L. at Beira Baixa are Galega vulgar, Bical and Cordovil de Castelo Branco. Humidity and oil content, by NMR, for the monovariety olive pastes were studied for two years, 1998/99 and 1999/2000.The results showed that Galega vulgar had significantly lower oil content when compared with Bical and Cordovil de Castelo Branco; but Bical and Cordovil de Castelo Branco did not differ significantly from each other concerning this parameter.The humidity values observed for the three cultivars are significantly different: Cordovil presents similar values during the three harvests while Galega vulgar and Bical showed their maximum values at the second harvest.

Research has been carried out to ascertain the influence of Lactobacillus pentosus DSM 16366 as freeze-dried cells and culture in nutritive media on fatty acid, sterol and triterpenic dialcohol compositions of ‘Azeiteira’ Spanish style green table olives. Results showed that there were no relevant differences on spontaneously or induced fermented fruit when comparing those compositions.

Contém referências bibliográficas

Contém referências bibliográficas

Comunicação apresentada no VII International Symposium of Temperate Zone Fruits in the Tropics and Subtropics, que decorreu em Florianópolis, Brasil, de 21 a 25 de Outubro de 2007. Foi organizado pela International Society of Horticultural Science.