AgriEngineering, Volume 2, Issue 1 (March 2020) – 11 articles

The emerging and vast adoption of the Internet of Things (IoT) has sprung a plethora of research works regarding the potential benefits in smart agriculture. A popular implementation involves the deployment of Wireless Sensor Networks (WSNs), which embed low energy consumption sensory nodes to capture the critical environmental parameters prevailing on the farms. However, to manage the ever-increasing volumes of raw data successfully, new approaches must be explored. Under this scope, current work reports on the design and development of an IoT system, having in mind the case of olive groves, which are considered the dominant sector for agricultural activity in the Mediterranean Basin. The system incorporates the cloud/fog computing paradigm to equip the olive growers with a low-cost solution for accurate, reliable, and almost real-time monitoring of their crops. Its core is based on a three-layered network architecture, capable of dynamically balancing the generated load, by pushing cloud-elastic resources to the underlying fog network. As such, the premise of the approach lies in the conforming character of the system that allows for targeted alterations to its operational functionality to meet stringent latency and traffic load environmental monitoring constraints. To evaluate the performance of the proposed architecture, a demo prototype is developed and deployed in the facilities of the Ionian University. Experimental results illustrate the efficiency, flexibility, and scalability of the approach in terms of latency, achieving response time reduction across all platforms, a subject of the utmost importance when it comes to precision agriculture of the future. Moreover, it is shown that the system is capable of dynamic functionality adaptation, to meet network traffic load constraints, achieving high throughput (on average 95%) and addressing potential environmental dangers to olive oil production. Full article

In this review, we examine opportunities and challenges for 21st-century robotic agricultural cotton harvesting research and commercial development. The paper reviews opportunities present in the agricultural robotics industry, and a detailed analysis is conducted for the cotton harvesting robot industry. The review is divided into four sections: (1) general agricultural robotic operations, where we check the current robotic technologies in agriculture; (2) opportunities and advances in related robotic harvesting fields, which is focused on investigating robotic harvesting technologies; (3) status and progress in cotton harvesting robot research, which concentrates on the current research and technology development in cotton harvesting robots; and (4) challenges in commercial deployment of agricultural robots, where challenges to commercializing and using these robots are reviewed. Conclusions are drawn about cotton harvesting robot research and the potential of multipurpose robotic operations in general. The development of multipurpose robots that can do multiple operations on different crops to increase the value of the robots is discussed. In each of the sections except the conclusion, the analysis is divided into four robotic system categories; mobility and steering, sensing and localization, path planning, and robotic manipulation. Full article

Estimation of chlorophyll content with portable meters is an easy way to quantify crop nitrogen status in sugar beet leaves. In this work, an alternative for chlorophyll content estimation using RGB-only vegetation indices has been explored. In a first step, pictures of spring-sown ‘Fernanda KWS’ variety sugar beet leaves taken with a commercial camera were used to calculate 25 RGB indices reported in the literature and to obtain 9 new indices through principal component analysis (PCA) and stepwise linear regression (SLR) techniques. The performance of the 34 indices was examined in order to evaluate their ability to estimate chlorophyll content and chlorophyll degradation in the leaves under different natural light conditions along 4 days of the canopy senescence period. Two of the new proposed RGB indices were found to improve the already good performance of the indices reported in the literature, particularly for leaves featuring low chlorophyll contents. The 4 best indices were finally tested in field conditions, using unmanned aerial vehicle (UAV)-taken photographs of a sugar beet plot, finding a reasonably good agreement with chlorophyll-meter data for all indices, in particular for I₂ and (R−B)/(R+G+B). Consequently, the suggested RGB indices may hold promise for inexpensive chlorophyll estimation in sugar beet leaves during the harvest time, although a direct relationship with nitrogen status still needs to be validated. Full article

Organic farming can play an important role in rural development and food production, by reinforcing the trend toward sustainable agriculture and its purpose of ecosystem conservation. The agribusiness of organic farming is particularly relevant in family farming, given the labor availability and the short marketing circuits. The innovative techniques of organic farming, namely with soil fertility, weed and pest control, opens a wide range of possibilities in its development and extension. The expectation of organic farming profitability in small-scale family farming, supported by known successful examples, were the theme of a field study on Lis Valley Irrigation District to assess the constraints to its expansion in order to outline the procedures for the acquisition of technical knowledge, the adaptation of technologies, the support for the conversion of production models, and the specialized training of farmers for action. Results revealed that the: (i) farmer’s land structure, (ii) their mature age, (iii) low education level, and (iv) markets, are the main constrains for organic farming development. Furthermore, other uncertainties were identified, namely: (i) the certification process, (ii) the knowledge of new technologies, especially of crop protection, and (iii) the marketing problems to guaranteeing profitability. This study concludes that organic farming has significant potential for development in the Lis Valley and that the efforts and resources of the various stakeholders, namely the state, need to be harmonized to deliver effective support to farmers to promote organic farming that prioritizes: (i) rural development policies, (ii) supporting land restructuring, (iii) modernization of irrigation, (iv) stimulation of young farmers, (v) conversion and implementation of innovative technologies, (vi) the organization of farmers for better productive efficiency, and (vii) to facilitate market access. Full article

Due to the complex manner in which secondary inorganic aerosols (SIAs) form, a need exists to develop a methodology to measure PM_2.5 emissions from agricultural operations to better understand the contribution of SIAs to the PM_2.5 fraction. When sampling particulate matter (PM), annular denuder systems (ADS) are a United States Environmental Protection Agency (US EPA) approved system used to measure both gaseous and particulate components of aerosols. While collecting basic gases, such as ammonia, using nine denuders was feasibly demonstrated in poultry housing units but the ability of additional denuders to accurately collect the SIAs on the filters is yet to be demonstrated. An experiment was designed to assess particle deposition behaviors throughout three different ADS configurations. It was determined that the nine denuder configuration resulted in particles being impacted and retained, mainly in the U-bend junctions, prior to reaching the filters with only 87.2% of PM_2.5 reaching the filter pack. The US EPA-prescribed ADS configuration had 99.4% of PM_2.5 reaching the filters, indicating that there is an impact due to the U-Bend addition to the system. It was further demonstrated that having additional denuders in series with no U-Bend had no significant impact on PM_2.5 deposition on the filters with 98.9% of PM_2.5 being collected. Full article

Irrigation districts play a decisive role in Portuguese agriculture and require the adaptation to the new water management paradigm through a change in technology and practices compatible with farmers’ technical know-how and economic sustainability. Therefore, improvement of water management, focusing on water savings and increasing farmers’ income, is a priority. In this perspective, an applied research study is being carried out on the gravity-fed Lis Valley Irrigation District to assess the performance of collective water supply, effectiveness of water pumping, and safety of crop production due to the practice of reuse of drainage water. The water balance method was applied at irrigation supply sectors, including gravity and Pumping Irrigation Allocation. The average 2018 irrigation water allocated was 7400 m³/ha, being 9.3% by pumping recharge, with a global efficiency of about 67%. The water quality analysis allowed identifying some risk situations regarding salinization and microbiological issues, justifying action to solve or mitigate the problems, especially at the level of the farmers’ fields, according to the crops and the irrigation systems. Results point to priority actions to consolidate improved water management: better maintenance and conservation of infrastructure of hydraulic infrastructures to reduce water losses and better flow control; implementation of optimal operational plans, to adjust the water demand with distribution; improvement of the on-farm systems with better water application control and maintenance procedures; and improvement of the control of water quality on the water reuse from drainage ditches. The technological innovation is an element of the modernization of irrigation districts that justifies the development of multiple efforts and synergies among stakeholders, namely farmers, water users association, and researchers. Full article

Phytophthora cinnamomi is responsible for radical rot in a wide range of hosts, resulting in large economic and ecological losses worldwide. In Spain, it is responsible for diseases such as the oak decline or the chestnut blight. In this study, different polyphenol-stevioside inclusion compounds dispersed in a hydroalcoholic solution of chitosan oligomers have been investigated, with a view to their application as natural bioactive complexes to replace conventional systemic fungicides against this fungus. The polyphenols tested in vitro were curcumin, ferulic acid, gallic acid and silymarin. Three concentrations (125, 250 and 500 µg·mL⁻¹) were assayed, with and without silver nanoparticles (AgNPs), and notable differences were found in the inhibition of mycelium growth, with EC₅₀ and EC₉₀ values ranging from 171 to 373.6 µg·mL⁻¹, and from 446.2 to 963.7 µg·mL⁻¹, respectively. The results obtained showed that the addition of AgNPs, despite their antimicrobial activity, did not always lead to synergies. In the case of P. cinnamomi, an unexpected antagonistic behavior was found for two of the polyphenols (curcumin and silymarin), while an additive behavior for ferulic acid and a synergistic behavior for gallic acid were attained. In view of their inhibitory power, the preparations based on ferulic acid with AgNPs and on silymarin without AgNPs are proposed for applications in crop and forests protection against P. cinnamomi. Full article

Tuber peeling is an essential unit operation prior to further processing. In this research, a batch loading tuber-peeling machine, with a capacity of 10 kg/min, was designed, fabricated and tested for cocoyam, sweet potato, yam and cassava tubers. The machine was designed to operate at a speed range of 350–750 rpm and time range of 5–12 min based on the principle of surface scratching. The performance of the machine was determined with respect to the peeling efficiency, percent weight of peel and flesh loss. The results showed that the peeling efficiency increased with an increase in the shaft speed for all the tubers. Also, the flesh loss and percent weight of peel decreased with an increase in the shaft speed for cassava and cocoyam tubers but increased for sweet potato and yam tubers (p < 0.05). Effective peeling of the tubers was achieved for sweet potato and yam at all the shaft speeds and time ranges considered. Full article

Steel greenhouse structures are generally constructed by individual sole contractors using quick empirical structural calculations (pre-engineered solutions). It is also common to import standard greenhouses from other countries, mainly from The Netherlands, Italy, and France, and sometimes from Great Britain and Israel. Evidently, these countries differ concerning the local wind and snow conditions. Therefore, there is a need for a better design of structures accepted as satisfactory, while installation can be done in a different location. Many greenhouse structures incorporating poor designs or inappropriate pre-engineered solutions are currently in use. At the same time, demolition and reconstruction represent a very expensive solution considering the loss of crop production and the demolition and construction costs; thus, strengthening is a reasonable alternative. This paper presents strengthening techniques for steel greenhouses that are code-deficient according to EN 13031 and Eurocodes. Consequently, two case studies are presented as typical applications of greenhouse structure strengthening. Full article

There has been increasing pressure on water resources in cities due to the proliferation of urban green areas. In the Mediterranean climate, only a small part of the plants’ water needs is supplied by rainfall during the winter months. Thus, in Algarve (Portugal) irrigation of the urban landscapes is required almost all year round. The aims of this study were to evaluate the maintenance of the urban landscapes of São Brás de Alportel (Algarve) during a year, based on the characterization of the vegetation of the urban gardens, the climate data, the analysis of the irrigation systems, the calculation of the plants water requirements and the normalized difference vegetation index (NDVI). By crossing all this information, it was possible to understand if the current maintenance level is the most suitable for sustainable irrigated urban landscapes. In most of the gardens, it was possible to establish a relationship between the gross irrigation water requirements and NDVI. In general, the NDVI allowed us to study the urban landscape, through the monthly observation of the differences in the appearance and development of the vegetation. Full article

We present an optimization model for dragon fruit plantations in Vietnam. The timing of cultivating and harvesting decisions are taken into account as the dragon fruit plant has an approximately ten-year life cycle with maximum average yield in the fourth year. Another consideration also included is the prevalence of forward-buying contracts with locked-in prices. The dragon fruit supply chain faces several difficulties as yield, price, and demand are highly sensitive to weather conditions and global uncertainty factors. The risk factors in the dragon fruit supply chain also depend on species—for example, the red varieties, while more profitable than the white varieties, also have higher export risk because they are subject to global prices and adverse geopolitical conditions. Full article