This review paper describes a novel approach to plant cultivation under soil-less culture. At present, global climate change is expected to raise the risk of frequent drought. Agriculture is in a phase of major change around the world and dealing with serious problems. In future, it would be difficult task to provide a fresh and clean food supply for the fast-growing population using traditional agriculture. Under such circumstances, the soil-less cultivation is the alternative technology to adapt effectively. The soil-less system associated with the Hydroponic and Aeroponics system. In the aeroponics system, plant roots are hanging in the artificially provided plastic holder and foam material replacement of the soil under controlled conditions. The roots are allowed to dangle freely and openly in the air. However, the nutrient rich-water deliver with atomization nozzles. The nozzles create a fine spray mist of different droplet size at intermittently or continuously. This review concludes that aeroponics system is considered the best plant growing method for food security and sustainable development. The system has shown some promising returns in various countries and recommended as the most efficient, useful, significant, economical and convenient plant growing system then soil and other soil-less methods.

In recent years, intelligent sensor techniques have achieved significant attention in agriculture. It is applied in agriculture to plan the several activities and missions properly by utilising limited resources with minor human interference. Currently, plant cultivation using new agriculture methods is very popular among the growers. However, the aeroponics is one of the methods of modern agriculture, which is commonly practiced around the world. In the system, plant cultivates under complete control conditions in the growth chamber by providing a small mist of the nutrient solution in replacement of the soil. The nutrient mist is ejected through atomization nozzles on a periodical basis. During the plant cultivation, several steps including temperature, humidity, light intensity, water nutrient solution level, pH and EC value, CO2concentration, atomization time, and atomization interval time require proper attention for flourishing plant growth. Therefore, the object of this review study was to provide significant knowledge about early fault detection and diagnosis in aeroponics using intelligent techniques (wireless sensors). So, the farmer could monitor several paraments without using laboratory instruments, and the farmer could control the entire system remotely. Moreover, the technique also provides a wide range of information which could be essential for plant researchers and provides a greater understanding of how the key parameters of aeroponics correlate with plant growth in the system. It offers full control of the system, not by constant manual attention from the operator but to a large extent by wireless sensors. Furthermore, the adoption of the intelligent techniques in the aeroponic system could reduce the concept of the usefulness of the system due to complicated manually monitoring and controlling process.

Traditionally, crops are cultivated in soil-based open field systems. Seasonality, environmental degradation, urbanization, and food security issues have replaced open-field systems with modern plant production systems. Soilless culture is one of the modern plant production systems, which involves much higher use of available resources. The presented study provides information about currently accessible soilless systems and discussed the aeroponic system. Compared to other soilless systems, aeroponic reduce water usage through continuous water circulation. However, the aeroponic is not entirely implemented among local farmers, and very few farmers have adopted the system due to the lack of research and technical information available in the literature. Therefore, this study was planned to provide information about the development and maintenance tasks required for practicing the aeroponic system. This study could provide knowledge to the researchers, farmers, and those people interested in practicing the aeroponic system.

HighlightsThe atomizer droplet size should be considered an important factor when designing aeroponic systems.Airless atomizers had significant positive effects on plant growth, total polyphenol content, and antioxidant activity.Airless atomizers and a spraying interval of 20 min on and 3 h off was the best combination for lettuce plants.Abstract. Throughout our literature review, the effects of various aeroponic atomizers (droplet sizes) on specific leafy plant growth and quality were minimally reported. Lettuce ( L.) is one of the most popular leafy vegetables consumed around the world. The present study sought to determine the effects of various aeroponic atomizers (droplet sizes) on the growth, total polyphenol content, and antioxidant activity of lettuce plants. Aeroponic systems were designed and manufactured using three kinds of atomizers: air-based (A1), airless (A2), and ultrasonic fogger (A3). The South China Agricultural leafy vegetable B nutrient solution was selected as the cultivating solution. Additionally, the spraying time and spraying interval were set at 20 min on and 3 h off. The sizes of the droplets generated by these atomizers were measured using a laser particle size analyzer, and the measured average droplet sizes generated by the A1, A2, and A3 atomizers were 23.281, 46.386, and 3.451 µm, respectively. The results showed that the lettuce plants treated with the A2 atomizers exhibited more significant effects on the growth, total polyphenol content, and antioxidant activity of the lettuce compared to those treated with the A1 and A3 atomizers. The results indicated that nutrient solution droplet size should be considered an essential factor when designing an aeroponic system. Keywords: Aeroponic, Antioxidant activity, Soilless, Spraying time, Total polyphenol content.

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Fruit recognition based on depth information has been a hot topic due to its advantages. However, the present equipment and methods cannot meet the requirements of rapid and reliable recognition and location of fruits in close shot for robot harvesting. To solve this problem, we propose a recognition algorithm for citrus fruit based on RealSense. This method effectively utilizes depth-point cloud data in a close-shot range of 160 mm and different geometric features of the fruit and leaf to recognize fruits with a intersection curve cut by the depth-sphere. Experiments with close-shot recognition of six varieties of fruit under different conditions were carried out. The detection rates of little occlusion and adhesion were from 80–100%. However, severe occlusion and adhesion still have a great influence on the overall success rate of on-branch fruits recognition, the rate being 63.8%. The size of the fruit has a more noticeable impact on the success rate of detection. Moreover, due to close-shot near-infrared detection, there was no obvious difference in recognition between bright and dark conditions. The advantages of close-shot limited target detection with RealSense, fast foreground and background removal and the simplicity of the algorithm with high precision may contribute to high real-time vision-servo operations of harvesting robots.

Determination of the mechanical properties (rupture force, deformation, hardness, and toughness) of maize grain could be a significant concern for designing the harvester, thresher, and handling, processing, and storage equipment. Thus, the present research was conducted to assess the vertical and lateral rupture force, deformation, hardness, and toughness of maize grain (Beijing Denong, Lianchuang, Suyu 20, Liyu 88 and Suyu 29) influenced by different moisture contents (11.2%, 17.5%, and 21.3%) and compressive loading speeds (5, 10, 15, 20, and 25 mm/min, respectively). Besides, the mean length, width, thickness, geometric mean diameter, equivalent diameter, arithmetic diameter, sphericity, grain volume, surface area, and aspect ratio of the selected varieties were measured. The results showed that the highest length, width, thickness and sphericity, grain volume, surface area, and aspect ratio were obtained at moisture of 21.3%, whereas the lowest was at 11.2%. Moreover, it was observed that as increasing the loading speed from 5 to 25 mm/min, the vertical and lateral rupture forces decreased. However, as increasing moisture contents from 11.2% to 21.3%, the vertical and lateral rupture forces, hardness, and toughness decreased noticeably. Furthermore, the maximum correlation (R 2 =0.9957) between rupture force and loading speed was found for Liyu 88 at moisture of 17.5% and minimum correlation (R 2 =0.7002) was found for Suyu 29 at moisture of 11.2%. Moreover, the highest lateral and vertical rupture force was noticed (p<0.05) at a loading speed of 5 mm/min. Based on the experimentally obtained results, it was concluded that the properties of maize grain evaluated were relevant to the design of planter, harvesters, thrashers, and processing machine.