Climate change and labour shortage are re-shaping farming methods. Agricultural tasks are often hard, tedious and repetitive for operators, and farms struggle to find specialized operators for such works. For this and other reasons (i.e., the increasing costs of agricultural labour) more and more farmers have decided to switch to autonomous (or semi-autonomous) field robots. In the past decade, an increasing number of robots has filled the market of agricultural machines all over the world. These machines can easily cover long and repetitive tasks, while operators can be employed in other jobs inside the farms. This paper reviews the current state-of-the-art of autonomous robots for agricultural operations, dividing them into categories based on main tasks, to analyze their main characteristics and their fields of applications. Seven main tasks were identified: multi-purpose, harvesting, mechanical weeding, pest control and chemical weeding, scouting and monitoring, transplanting and tilling-sowing. Field robots were divided into these categories, and different characteristics were analyzed, such as engine type, traction system, application field, safety sensors, navigation system, country of provenience and presence on the market. The aim of this review is to provide a global view on agricultural platforms developed in the past decade, analyzing their characteristics and providing future perspectives for next robotic platforms. The analysis conducted on 59 field robots, those already available on the market and not, revealed that one fifth of the platforms comes from Asia, and 63% of all of them are powered by electricity (rechargeable batteries, not solar powered) and that numerous platforms base their navigation system on RTK-GPS signal, 28 out of 59, and safety on LiDAR sensor (12 out of 59). This review considered machines of different size, highlighting different possible choices for field operations and tasks. It is difficult to predict market trends as several possibilities exist, like fleets of small robots or bigger size platforms. Future research and policies should focus on improving navigation and safety systems, reducing emissions and improving level of autonomy of robotic platforms.

Organic vegetable production is particularly affected by weed pressure and mechanical weeding is the major tactic implemented by growers to keep weeds under economic thresholds. Living mulch (LM) has been shown to provide several environmental services; however, LM management is required to avoid competition between service crops and cash crops. The aim of this trial was to evaluate two innovative LM-based management systems: a system that provided LM growth regulation by means of flaming (LM-FL) and a system where the LM was regularly mowed by an autonomous mower (LM-AM), both compared with a control without LM and based on standard tillage operations (TILL). The three management systems were evaluated in terms of crop production, weed control, and energy consumption on a 2 yr organic crop rotation of cauliflower (Brassica oleracea L. var botrytis) and eggplant (Solanum melongena L.). LM-AM produced an acceptable fresh marketable yield for both vegetable crops. Moreover, the weed dry biomass obtained in LM-AM-managed plots was lower compared to the LM-FL plots and ranged approximately from 200 to 300 kg ha⁻¹. Furthermore, LM-AM management resulted in lower energy consumption (−2330 kWh ha⁻¹ with respect to the TILL system and −7225 kWh ha⁻¹ with respect to the LM-FL system). The results of this trial suggest that autonomous mowers have a great potential to improve LM management and help with implementing sustainable organic vegetable systems.

Mechanical under-row weed control in the vineyard emerges as a sustainable choice compared to chemical control, with tillage-based approaches proving especially efficient. A rollhacke, finger weeder, and blade weeder are valid alternatives to commonly used implements that cause excessive soil disruption and display suboptimal efficiency. The trial aimed to compare different under-row weed control strategies in terms of weed control efficacy and operational performance. Among these, in ST1, a tool-holder equipped with both a rollhacke and finger weeder was used at the first and second intervention; in ST2, a rollhacke was used at the first intervention and blade weeder at the second one; in ST3, firstly the tool-holder equipped with a rollhacke and finger weeder was used, then the blade weeder; in ST4, a rollhacke was used first and then the tool-holder equipped with a rollhacke and finger weeder. Weed height, weed cover, and weed biomass were evaluated before the first and after the second intervention. Total field time, fuel consumption, and CO₂ emissions of each strategy were assessed. ST1 proved to be the best compromise in terms of weed control effectiveness and operational performance compared to the other strategies. Indeed, ST1 tendentially achieved a lower weed height (20.42 cm) and weed biomass around vine trunks (105.33 g d.m. m⁻²) compared to the other strategies. In terms of total field time, fuel consumption and CO₂ emissions, ST1 recorded intermediate values equal to 3.85 h ha⁻¹, 15.29 kg ha⁻¹, and 48.72 kg ha⁻¹, respectively. Further studies are needed to evaluate these strategies in different vineyard conditions, considering their effect on weed flora composition. Furthermore, exploring automation technology for real-time implement adjustments based on weed infestation levels could further improve the intervention effectiveness and efficiency.

Robotic solutions and technological advances for turf management demonstrated excellent results in terms of quality, energy, and time consumption. Two battery-powered autonomous mowers (2 WD and 4 WD) with random patterns were evaluated according to different trampling levels (control, low, medium, high) on a typical warm season turfgrass at the DAFE, University of Pisa, Italy. Data on the percentage of area mowed, the distance traveled, the number of passages, and the number of intersections were collected through RTK devices and processed by a custom-built software (1.8.0.0). The main quality parameters of the turfgrass were also analyzed by visual and instrumental assessments. Soil penetration resistance was measured through a digital penetrometer. The efficiency significantly decreased as the trampling level increased (from 0.29 to 0.11). The over-trampled areas were mainly detected by the edges (on average for the medium level: 18 passages for the edges vs. 14 in the central area). The trampling activity caused a reduction in turf height (from about 2.2 cm to about 1.5 cm). The energy consumption was low and varied from 0.0047 to 0.048 kWh per cutting session. Results from this trial demonstrated suitable quality for a residential turf of the Mediterranean area (NDVI values from 0.5 to 0.6), despite the over-trampling activity. Soil penetration data were low due to the reduced weight of the machines, but slightly higher for the 4 WD model (at 5 cm of depth, about 802 kPa vs. 670 kPa).

Several trials have been carried out by various authors concerning autonomous mowers, which are battery-powered machines. The effects of these machines on turfgrass quality and energy consumption have been thoroughly investigated. However, there are still some aspects that have not been studied. Among these, random trajectory overlapping is one of the most important. To investigate these aspects, two RTK-GPS devices along with the custom-built software used for previous trials has been upgraded in order to precisely calculate how many times the mower drives over the same spot using random trajectories. This parameter, the number of passages in the same position, was hypothesized to explain the autonomous mower’s overlapping and trampling action. The trial has been carried out testing a commercial autonomous mower on three areas with different levels of complexity to assess its performances. The following variables were examined: the percentage of mowed area, the distance travelled, the number of intersections, the number of passages, and the autonomous mower’s work efficiency. The average percentage of area mown (average value for the three areas) was 54.64% after one hour and 80.15% after two hours of work. Percentage of area mown was 15% higher for the area with no obstacles after two hours of work. The number of passages was slightly different among the three garden designs. The garden with no obstacles obtained the highest number of passages with an average of 37 passages. The highest working efficiency was obtained in the garden with an intermediate number of obstacles with a value of 0.40 after two hours of work. The estimated energy consumption resulted 0.31 Wh m⁻² after one hour and 0.42 Wh m⁻² after two hours of working. These results highlight how the correct settings of cutting time may be crucial to consistently save energy during the long period and may be useful for a complete automation of the maintenance of green areas.

Conservation agriculture practices, such as reduced tillage and the incorporation of cover crops, play a crucial role in improving the sustainability of organic farming systems. The aim of this two-year field trial was to evaluate five different organic technical itineraries (ST, IN1, IN2, M1, and M2) which differed on soil management practices adopted before processing tomato transplantation and regarding weed control strategies performed. Soil management practices in comparison consisted of conventional deep tillage (ST and M1) or reduced tillage together with the use of a cover crop mixture composed of common vetch and barley (IN1, IN2, and M2). Weed control strategies involved the use of biodegradable mulch together with mechanical weeding (ST and M2), or false seedbed technique and mechanical weeding (IN1, IN2, and M1). Weed biomass at harvest, tomato yield, and the operational and economic performance of each of the technical itineraries was evaluated. No significant differences emerged in terms of weed biomass at harvest between itineraries. Best yield results were obtained tendentially by ST and M2 when biodegradable mulch was used, with values equal to 42.14 and 41.47 Mg ha⁻¹ in 2020 and 30.68 and 31.19 Mg ha⁻¹ in 2021, respectively. Even though the itineraries where mulch film was used (ST and M2) resulted in significantly onerous processes, they also obtained the highest gross income compared to the other itineraries, with values of 30,998 and 29,900 € ha⁻¹ in 2020, and of 16,060 and 15,186 € ha⁻¹ in 2021, respectively. These results revealed the importance of using mulching to help cope with critical climatic conditions, such as drought seasons. Further studies are needed to evaluate the yield and economic advantages of both the effect of shallower soil tillage over a longer period in this specific context and the creation of ground cover with cover crops managed as dead mulch.