Search Results (163)

‘Pera’ sweet orange is a key variety for the Brazilian citrus industry, but orchards rely on a limited number of clonal selections, which restricts adaptability and productivity across diverse environments. This study assessed the agronomic performance of 13 ‘Pera’ selections grafted on Rangpur lime, cultivated under rainfed conditions in subtropical Brazil. From 2002 to 2010, trees were assessed for vegetative growth, cumulative yield, alternate bearing, and fruit quality. Market-specific performance indices were calculated to determine suitability for fresh fruit or juice processing. Substantial genotypic variation was observed across traits, particularly during early orchard stage. Selections such as ‘Morretes’, ‘Seleção 11’, ‘Seleção 27’, ‘Seleção 37’, and ‘IPR 153’ demonstrated high cumulative yield, stable productivity, and favorable canopy traits, supporting their use in both conventional and high-density systems. ‘IPR 153’ combined compact growth with high yield efficiency and excellent fruit quality, while ‘Morretes’ had the highest juice content and broad market adaptability. In contrast, ‘IPR 159’ showed low vigor and yield under rainfed conditions. The results emphasize the value of regionally targeted clonal selection to improve orchard performance and market alignment. The identification of dual-purpose genotypes offers a pathway to diversify citrus production and improve profitability under subtropical growing conditions. Full article

The sustainability of Korla fragrant pear orchards has been increasingly threatened by prolonged intensive agricultural practices. In response, biofertilizers and green manures have gained attention due to their potential to enhance soil structure, activate microbial functions, and improve nutrient uptake. However, the dynamic changes in soil bacterial communities under such interventions remain inadequately understood. This study was conducted from 2022 to 2023 in 7- to 8-year-old Korla fragrant pear orchards in Bayin’guoleng Mongol Autonomous Prefecture, Xinjiang. The treatments included: conventional fertilization (CK), biofertilizer (JF), oil sunflowers (DK1) with 25 cm row spacing and a seeding rate of 27 kg·hm⁻², oil sunflowers (DK2) with 25 cm row spacing and a seeding rate of 33 kg·hm⁻², sweet clover (CM1) with 20 cm row spacing and a seeding rate of 21 kg·hm⁻², and sweet clover (CM2) with 20 cm row spacing and a seeding rate of 27 kg·hm⁻². During the 2023 pear season, soil samples from the 0–20 cm layer were collected at the fruit setting, expansion, and maturity stages. Their physical and chemical properties were analyzed, and the structure and diversity of the soil bacterial community were examined using 16S rRNA gene high-throughput sequencing. Fruit yield was assessed at the maturity stage. Compared to CK, the relative abundance of Actinobacteria increased by 101.00%, 38.99%, and 50.38% in the JF, DK2, and CM1 treatments, respectively. DK1 and CM1 treatments resulted in a 152.28% and 145.70% increase in the relative abundance of the taxon Subgroup_7, while JF and DK2 treatments enhanced the relative abundance of the taxon Gitt-GS-136 by 318.91% and 324.04%, respectively. The Chao1 index for CM2 was 18.76% higher than CK. LEfSe analysis showed that the DK2 and CM2 treatments had a more significant regulatory effect on bacterial community structure. All treatments led to higher fruit numbers and yield compared to CK, with JF showing the largest yield increase. Fertilizer type, soil nutrients, and bacterial community structure all significantly positively influenced pear yield. In conclusion, high-density oil sunflower planting is the most effective approach for maintaining soil microbial community stability, followed by low-density sweet clover. This study provides a systematic evaluation of the dynamic effects of bio-fertilizers and different green manure planting patterns on soil microbial communities in Korla fragrant pear orchards, presenting practical, microbe-based strategies for sustainable orchard management. Full article

The adaptability of several Italian olive cultivars to high-density cultivation was evaluated from 2020 to 2024 in central Italy by assessing their agronomic behavior, with the aim of identifying which Italian olive cultivars can combine high productivity and suitability for intensive mechanization—through high- and very high-density planting systems—allowing biodiversity valorization. The cultivars were Borgiona, Don Carlo, FS17, Gentile di Anghiari, Gentile di Montone, Giulia, Leccio del Corno, Maurino, Moraiolo, Pendolino, Piantone di Falerone, and Piantone di Mogliano. The international cultivar Arbequina was used as a reference. The olive orchard was planted in 2015, at a tree spacing of 5 m × 2 m (1000 trees/ha). Arbequina was found to have limited vigor and high production efficiency, as reported in other works, therefore confirming its suitability for high-density and super-high-density cultivation. Some cultivars, such as Leccio del Corno, Maurino, FS17, Piantone di Mogliano, and Piantone di Falerone, had a production and yield efficiency that was not different from or even higher than Arbequina. Other cultivars found to be promising were Don Carlo and Gentile di Anghiari, which had a slightly lower productive performance than Arbequina. Overall, the results are encouraging and suggest that some of these cultivars may be suitable candidates for high- and super-high-density olive orchards. This suitability is further supported by their favorable fruit characteristics, which appear to facilitate efficient mechanical harvesting. However, additional data is necessary to enable a more comprehensive assessment of these cultivars, particularly their capacity to maintain canopy dimensions compatible with straddle harvester operation, while maintaining a stable vegetative–reproductive balance over time. Full article

The olive industry is transitioning from traditional to super-high-density (SHD) systems to optimize production costs and address labor shortages. This shift coincides with increasing challenges from soil salinization and deteriorating irrigation water quality. This study evaluated salinity tolerance in three novel olive cultivars (Lecciana, Coriana, and Sikitita) against the established SHD references Arbequina and Arbosana under controlled greenhouse conditions over five months with increasing NaCl concentrations (25, 50, and 75 mM). The analysis revealed distinct adaptation mechanisms among cultivars. Arbosana exhibited balanced tolerance across parameters, with minimal biomass reduction and remarkable photosynthetic resilience. Lecciana demonstrated superior ion regulation, maintaining the highest K⁺/Na⁺ ratios across all salinity levels despite pronounced shoot growth sensitivity at high salinity. Sikitita showed moderate tolerance through biomass maintenance but with significant photosynthetic sensitivity under stress. Arbequina displayed effective chloride exclusion and consistent shoot growth despite biomass sensitivity, whereas Coriana presented notable biomass increases at moderate salinity but poor ion discrimination. Tissue-specific analysis revealed common compartmentalization patterns across cultivars, with roots accumulating the highest Na⁺ and Cl⁻ concentrations. These data identify Arbosana and Lecciana as promising candidates for salinized SHD orchards. Full article

In recent years, the traditional orchard sprayer has had problems, such as waste of liquid agrochemicals, low target coverage, high manual dependence, and environmental pollution. In this study, an automatic swing-arm sprayer for orchards was developed based on the standardized pear orchard in Pinggu, Beijing. Firstly, the structural principles of a crawler-type traveling system and swing-arm sprayer were simulated using finite element software design. The combination of a diffuse reflection photoelectric sensor and Arduino single-chip microcomputer was used to realize real-time detection and dynamic spray control in the pear canopy, and the sensor delay compensation algorithm was used to optimize target recognition accuracy and improve the utilization rate of liquid agrochemicals. Through the integration of innovative structural design and intelligent control technology, a vertical droplet distribution test was carried out, and the optimal working distance of the spray was determined to be 1 m; the nozzle angle for the upper layer was 45°, that for the lower layer was 15°, and the optimal speed of the swing-arm motor was 75 r/min. Finally, a particle size test and field test of the orchard sprayer were completed, and it was concluded that the swing-arm mode increased the pear tree canopy droplet coverage by 74%, the overall droplet density by 21.4%, and the deposition amount by 23% compared with the non-swing-arm mode, which verified the practicability and reliability of the swing-arm spray and achieved the goal of on-demand pesticide application in pear orchards. Full article

Traditional rainfed fig orchards intended for fresh consumption tend to have low yields and cultural practices difficulties due to wide plant spacing and large canopies. This study investigates whether the espalier training system, commonly employed in other fruit species, can be applied to fig cultivation to improve productivity and fruit quality under high-density irrigated plantations. For the first time, four fig varieties (‘San Antonio’, ‘Dalmatie’, ‘Albacor’, and ‘De Rey’) were evaluated in a high-density system (625 trees/ha) using espalier training over four consecutive years (2018–2021) in southwestern Spain. Among the varieties, ‘Dalmatie’ demonstrated the highest suitability to the system, combining low vegetative vigour with superior yield performance, reaching a cumulative yield of 103.15 kg/tree and yield efficiency of 1.94 kg/cm². ‘San Antonio’ was the earliest to ripen and exhibited the longest harvest duration (81 days), enabling early and extended market availability. In terms of fruit quality, ‘Albacor’ stood out for its high total soluble solids content (24.97 °Brix), while ‘De Rey’ exhibited the best sugar–acid balance, with a maturity index of 384.58. The present work demonstrates that intensive fig cultivation on espalier structures offers an innovative alternative to traditional systems, thereby enhancing orchard efficiency, management, and fruit quality. Full article

Olive trees are generally considered a species well-adapted to drought, but the impact of water shortage is of critical importance on olive production. For this reason, developing tolerant cultivars could be an effective strategy to mitigate the impact of drought in the future. Characterizing drought stress tolerance in olive is a complex task due to the numerous traits involved in this response. In this study, plant growth, pressure–volume curves, gas-exchange and chlorophyll fluorescence traits, and stomata characteristics were monitored in nine cultivars to assess the effects of mild and severe drought stress conditions induced by withholding water for 7 and 21 days, respectively, and were compared to a well-watered control treatment. The plant materials evaluated included traditional cultivars, as well as new developed cultivars suited for high-density hedgerow olive orchards or resistant to verticillium wilt. Significant differences between cultivars were observed for most evaluated traits, with more pronounced differences under severe drought conditions. A multivariate analysis of the complete dataset recorded throughout the evaluation period allowed for the identification of promising cultivars under stress conditions (‘Sikitita’, ‘Sikitita-2’, and ‘Martina’) as well as highly discriminative traits that could serve as key selection parameters in future breeding programs. Full article

This study investigated carbon dynamics in a peach orchard subjected to three treatments with a mixed compost amendment (MCA, 35% organic content): a control with no amendment (A0), a full dose (A1, 10 t ha⁻¹), and a half dose (A2, 5 t ha⁻¹). The sustainability of MCA was assessed in terms of (i) potential and (ii) actual soil respiration, (iii) soil carbon and physical properties and (iv) fruit quality and yield. Carbon dioxide (CO₂) emissions were measured both in the laboratory, by incubating soil samples without root removal, and in the field using static chambers. Observations spanned three growing seasons (2021–2023). A correlation was found between actual and potential soil respiration, with emission peaks occurring near the time of MCA application. Cumulative actual CO₂ emissions amounted to 5.6, 12.0 and 9.4 t CO₂ ha⁻¹ for A0, A1 and A2, respectively. MCA application (i) increased microbial respiration, (ii) reduced soil physical characteristics, such as bulk density and water-filled pore space, and (iii) slightly improved fruit quality, although the yield was not significantly affected. Furthermore, the MCA enhanced soil organic carbon and total nitrogen content compared to the control. These results suggest that high organic content amendments, such as MCA, could represent a strategy to maintain or increase soil organic matter in a sustainable way, although MCA does not improve carbon emission efficiency. Full article

In mountainous citrus orchards, the application of conventional ground sprayers for the control of citrus red mite (Panonychus citri) is often constrained by complex terrain and low operational efficiency. The Unmanned Aerial Spraying System (UASS), due to its low-altitude, low-volume, and high-maneuverability characteristics, has emerged as a promising alternative for pest management in such challenging environments. To evaluate the spray performance and field efficacy of different UASS types in controlling P. citri, five representative UASS models (JX25, DP, T1000, E-A2021, and T20), four mainstream pesticide formulations, and four novel tank-mix adjuvants were systematically assessed in a field experiment conducted in a typical hilly citrus orchard. The results showed that T20 delivered the best overall spray deposition, with upper canopy coverage reaching 10.63%, a deposition of 3.01 μg/cm², and the highest pesticide utilization (43.2%). E-A2021, equipped with a centrifugal nozzle, produced the finest droplets and highest droplet density (120.3–151.4 deposits/cm²), but its deposition and coverage were lowest due to drift. Nonetheless, it exhibited superior penetration (dIPR 72.3%, dDPR 73.5%), facilitating internal canopy coverage. T1000, operating at higher flight parameters, had the weakest deposition. Formulation type had a limited impact, with microemulsions (MEs) outperforming emulsifiable concentrates (ECs) and suspension concentrates (SCs). All adjuvants improved spray metrics, especially Yimanchu and Silwet, which enhanced pesticide utilization to 46.8% and 46.4% for E-A2021 and DP, respectively. Adjuvant use increased utilization by 4.6–11.9%, but also raised ground losses by 1.5–4.2%, except for Yimanchu, which reduced ground loss by 2.3%. In terms of control effect, the rapid efficacy (1–7 days after application, DAA) of UASS spraying was slightly lower than that of ground sprayers—electric spray gun (ESG), while its residual efficacy (14–25 DAA) was slightly higher. The addition of adjuvants improved both rapid and residual efficacy, making it comparable to or even better than ESG. E-A2021 with 5% abamectin·etoxazole ME (5A·E) and Yimanchu achieved 97.4% efficacy at 25 DAA. Among UASSs, T20 showed the rapid control, while E-A2021 outperformed JX25 and T1000 due to finer droplets effectively targeting P. citri. In residual control (14–25 DAA), JX25 with 45% bifenazate·etoxazole SC (45B·E) was most effective, followed by T20. 5A·E and 45B·E showed better residual efficacy than abamectin-based formulations, which declined more rapidly. Adjuvants significantly extended control duration, with Yimanchu performing best. This study demonstrates that with optimized spraying parameters, nozzle types, and adjuvants, UASSs can match or surpass ground spraying in P. citri control in hilly citrus orchards, providing valuable guidance for precision pesticide application in complex terrain. Full article

To address the challenge of low operational efficiency in apple harvesting robots, this study proposes an adaptive grasping sequence planning methodology that combines Self-Organizing Maps (SOMs) and genetic algorithms (GAs). The proposed adaptive SOM—GA hybrid algorithm aims to minimize cycle time by optimizing the path planning between the fruit detection and grasping phases. First of all, we propose a density-aware adaptive mechanism that dynamically adjusts planning strategies based on fruit count thresholds. In addition, the proposed grasping sequence planning framework for high-density dwarf cultivation (HDDC) orchards is validated through threshold sensitivity analysis and empirical analysis of over 500 real-world fruit distribution samples. Finally, comparative experiments demonstrate that our proposed method reduces path length in high-density scenarios. Statistical analysis reveals a bimodal fruit distribution, which aligns the algorithm’s adaptive thresholds with real-world operational demands. These advancements improve theoretical research and enhance the commercial viability in agricultural robotics. Full article

Precision irrigation requires reliable estimates of crop evapotranspiration (ET) using site-specific crop and weather data inputs. Such estimates are needed at high resolutions which have been minimally explored for heterogeneous crops such as orchards. In addition, weather information for estimating ET is very often selected from sources that do not represent conditions like heterogeneous site-specific conditions. Therefore, a study was conducted to map geospatial ET and transpiration (T) of a high-density modern apple orchard using high-resolution aerial imagery, as well as to quantify the impact of site-specific weather conditions on the estimates. Five campaigns were conducted in the 2020 growing season to acquire small unmanned aerial system (UAS)-based thermal and multispectral imagery data. The imagery and open-field weather data (solar radiation, air temperature, wind speed, relative humidity, and precipitation) inputs were used in a modified energy balance (UASM-1 approach) extracted from the Mapping ET at High Resolution with Internalized Calibration (METRIC) model. Tree trunk water potential measurements were used as reference to evaluate T estimates mapped using the UASM-1 approach. UASM-1-derived T estimates had very strong correlations (Pearson correlation [r]: 0.85) with the ground-reference measurements. Ground reference measurements also had strong agreement with the reference ET calculated using the Penman–Monteith method and in situ weather data (r: 0.89). UASM-1-based ET and T estimates were also similar to conventional Landsat-METRIC (LM) and the standard crop coefficient approaches, respectively, showing correlation in the range of 0.82–0.95 and normalized root mean square differences [RMSD] of 13–16%. UASM-1 was then modified (termed as UASM-2) to ingest a locally calibrated leaf area index function. This modification deviated the components of the energy balance by ~13.5% but not the final T estimates (r: 1, RMSD: 5%). Next, impacts of representative and non-representative weather information were also evaluated on crop water uses estimates. For this, UASM-2 was used to evaluate the effects of weather data inputs acquired from sources near and within the orchard block on T estimates. Minimal variations in T estimates were observed for weather data inputs from open-field stations at 1 and 3 km where correlation coefficients (r) ranged within 0.85–0.97 and RMSD within 3–13% relative to the station at the orchard-center (5 m above ground level). Overall, the results suggest that weather data from within 5 km radius of orchard site, with similar topography and microclimate attributes, when used in conjunction with high-resolution aerial imagery could be useful for reliable apple canopy transpiration estimation for pertinent site-specific irrigation management. Full article

To address uneven airflow distribution and pesticide deposition coverage in orchard pesticide application, we developed a double-flexible duct spraying device. Utilizing FLUENT 2022 software for airflow field simulation, we analyzed various structural parameters to identify optimal configurations for the air duct type, diameter, and nozzle outlet diameter. The results indicated that the nozzle outlet diameter most significantly influences wind field uniformity, followed by the air duct diameter and type. The optimal settings were identified as follows: C-Type air duct, 100 mm duct diameter, and 50 mm nozzle outlet diameter. Validation tests confirmed these settings, with simulated and actual wind speed measurements, showing no more than a 10% relative error, affirming the simulation’s accuracy. Field tests demonstrated an average droplet density of 35.38 droplets/cm² within tree canopies, indicating strong penetration ability. Droplet distribution followed a lower > middle > upper pattern in the canopy’s vertical direction, fulfilling technical requirements for high spindle-shaped fruit trees and providing a foundation for achieving a uniform canopy coverage. Full article

This paper proposes an enhanced RRT* algorithm (XN-RRT*) to address the challenges of low path planning efficiency and suboptimal picking success rates in complex pitaya harvesting environments. The algorithm generates sampling points based on normal distribution and dynamically adjusts the center and range of the sampling distribution according to the target distance and tree density, thus reducing redundant sampling. An improved artificial potential field method is employed during tree expansion, incorporating adjustment factors and target points to refine the guidance of sampling points and overcome local optima and infeasible targets. A greedy algorithm is then used to remove redundant nodes, shorten the path, and apply cubic B-spline curves to smooth the path, improving the stability and continuity of the robotic arm. Simulations in both two-dimensional and three-dimensional environments demonstrate that the XN-RRT* algorithm performs effectively, with fewer iterations, high convergence efficiency, and superior path quality. The simulation of a six-degree-of-freedom robotic arm in a pitaya orchard environment using the ROS2 platform shows that the XN-RRT* algorithm achieves a 98% picking path planning success rate, outperforming the RRT* algorithm by 90.32%, with a 27.12% reduction in path length and a 14% increase in planning success rate. The experimental results confirm that the proposed algorithm exhibits excellent overall performance in complex harvesting environments, offering a valuable reference for robotic arm path planning. Full article

Stone fruits (Prunus spp.) occupy a pivotal position in global fruit production due to their significant nutritional profile and distinctive organoleptic characteristics. Contemporary orchard systems are undergoing transformation through innovative cultivation approaches, notably high-density dwarfing systems, greenhouse cultivation, agri-tech integration, and simplified management. As a crucial agronomic component in modern stone fruit cultivation, rootstock systems confer multi-benefits including enhanced environmental resilience, improved scion productivity, superior fruit quality, controlled vigor, and dwarfing capacity. While the majority of European apple orchards have transitioned to dwarfing rootstock systems, achieving substantial gains in productivity and profitability, stone fruit cultivation lags significantly due to the key gaps in prunus rootstock development, including genetic complexity, extended evaluation cycles, clonal propagation barriers, and limited research programs. Urgent innovation is required to address these challenges in rootstock breeding to meet the demand of sustainable stone fruit production. This review systematically examines strategic breeding objectives and innovative molecular methodologies in prunus rootstock development, with particular emphasis on marker-assisted selection and genomic prediction technologies. We provide a comprehensive synthesis of breeding achievements across major commercial rootstock cultivars, while proposing forward-looking research strategies incorporating CRISPR-based genome editing and multi-omics approaches. The synthesized insights establish a theoretical pathway for advancing rootstock genetic improvement and sustainable orchard management practices in stone fruit cultivation systems. Full article

The main objective of this study was to evaluate the changes in soil water retention curve (WRC) and pore size distribution in the 0–10, 10–20, and 20–30 cm layers following grassland conversion into arable land and an avocado orchard. Undisturbed soil cores were sampled using cylindrical metal cores to determine WRCs. The RETC program was used to fit the van Genuchten equation to the measured water retention data. The maximum equivalent radius (r) of soil pores retaining water at various matric potentials was calculated using the capillary rise equation. Significant differences between treatments were observed mainly in the 10–20 cm layers. Greater θ_s, n, and α in grassland were attributed to low bulk density and high soil organic carbon. Soil compaction in arable land and an avocado orchard was attributed to soil disturbance. The grassland had a greater share of macro- and mesopore volumes and large air capacity than the arable and avocado orchard. Overall, the results indicated that the conversion of native grassland causes substantial changes in soil hydraulic properties that could impact crop growth and the environment. Full article