Empowering vertical farming through IoT and AI-Driven technologies: A comprehensive review

The substantial increase in the human population dramatically strains food supplies. Farmers need healthy soil and natural minerals for traditional farming, and production takes a little longer time. The soil-free farming method known as vertical farming (VF) requires a small land and consumes a very small amount of water than conventional soil-dependent farming techniques. With modern technologies like hydroponics, aeroponics, and aquaponics, the notion of the VF appears to have a promising future in urban areas where farming land is very expensive and scarce. VF faces difficulty in the simultaneous monitoring of multiple indicators, nutrition advice, and plant diagnosis systems. However, these issues can be resolved by implementing current technical advancements like artificial intelligence (AI)-based control techniques such as machine learning (ML), deep learning (DL), the internet of things (IoT), image processing as well as computer vision. This article presents a thorough analysis of ML and IoT applications in VF system. The areas on which the attention is concentrated include disease detection, crop yield prediction, nutrition, and irrigation control management. In order to predict crop yield and crop diseases, the computer vision technique is investigated in view of the classification of distinct collections of crop images. This article also illustrates ML and IoT-based VF systems that can raise product quality and production over the long term. Assessment and evaluation of the knowledge-based VF system have also been outlined in the article with the potential outcomes, advantages, and limitations of ML and IoT in the VF system.

Closing the nutrient cycle in urban areas: The use of municipal solid waste in peri-urban and urban agriculture

Cities face the challenges of supplying food and managing organic municipal solid waste (OMSW) sustainably amid increasing urbanization rates. Urban agriculture (UA) can help with this effort by producing local crops that are fertilized with nutrients recovered from compost generated from OMSW. This research aims to determine the potential of OMSW compost to supply the nitrogen-phosphorus-potassium (NPK) demand of UA and the environmental benefits of replacing mineral fertilizer from a life cycle perspective. The Metropolitan Area of Barcelona (AMB) serves as the case study given its commitment to reuse biowaste according to the Revised Waste Framework Directive and to promote UA as a signing member of the Milan Urban Food Policy Pact. Based on crop requirements and farmer surveys, we find that the annual NPK demands of the agricultural fields of the AMB that cover 5,500 ha and produce 70,000 tons of crops are approximately 769, 113, and 592 tons of NPK, respectively. Spatial material flow analysis and life cycle assessment were applied to found that the current waste management system can potentially substitute 8 % of the total NPK demanded by UA with compost, reduce the impacts by up to 39 % and yield savings in global warming of 130 %. The more ambitious future scenario of 2025 can potentially substitute 21 % of the total NPK demand and reduce environmental impacts up to 1,049 %, depending on the category considered. Avoiding processing of mixed OMSW, mineral fertilizer replacement and cogeneration of electricity from biogas are the major contributors to these environmental savings.

Fresh bell peppers consumed in cities: Unveiling the environmental impact of urban and rural food supply systems

Agriculture and its supply chain pose significant environmental threats. This study employs Life Cycle Assessment (LCA) to explore the environmental impact of fresh bell pepper production and distribution, comparing Urban and Peri-Urban Agriculture (UPA) with Rural Long-Distance Food Supply Systems (RLDFS). Four UPA scenarios (hydroponics, soil-based greenhouse, open-field conventional, and organic) and two RLDFS scenarios (soil-based greenhouse and open-field conventional) are evaluated using SimaPro, incorporating inputs from UPA practitioners and rural farmers. Results reveal an energy demand range of 0.011 to 5.5 kWh/kg eq., with urban greenhouses exhibiting the lowest consumption and hydroponics the highest due to lighting, ventilation, and irrigation. Hydroponics exhibits a global warming potential of 7.24 kg of CO2 eq·kg-1, with energy demand contributing over 95 %, surpassing other scenarios by 7-25 times, necessitating reduction for sustainability. RLDFS's environmental impact is dominated by transportation (over 70 %), meanwhile other UPA systems are influenced by irrigation, infrastructure, and fertilizers. Despite challenges, UPA-hydroponics proves to be 1.7 to 4.3 times more land-use-efficient than other scenarios, emphasizing its potential. The study highlights the need to address electricity usage in UPA-hydroponics for carbon footprint reduction. Despite challenges, hydroponics could contribute to sustainable food security, and RLDFS does not significantly lag in environmental performance compared to UPA other than Ozone layer depletion criteria attributed to fossil fuel usage in transportation. These insights offer valuable guidance for urban development and policy formulation, promoting sustainable agricultural practices and supporting policies for agronomic and supply chain sustainability.

Displaying geographic variability of peri-urban agriculture environmental impacts in the Metropolitan Area of Barcelona: A regionalized life cycle assessment

Peri urban agriculture (peri-UA) can supply food locally and potentially more sustainably than far-away conventional agricultural systems. It can also introduce significant environmental impacts depending on the local biophysical conditions and resources required to implement it and, on the crops managing practices, which could vary widely among growers. Sophisticated methods to account for such variability while assessing direct (on-site) and indirect (up/down stream) environmental impacts of peri-UA implementation are thus needed. We implemented an attributional, regionalized, cradle-to-gate life cycle assessment (LCA) for which we derive spatially explicit inventories and calculate 14 impacts due to peri-UA using the ReCiPe method. Further, to show the importance of impact assessment regionalization for the environmental assessment of peri-UA, we regionalize eutrophication impacts characterization. We use the Metropolitan Area of Barcelona (AMB) to illustrate these methodological developments. Vegetables and greenhouses, the prevalent peri-UA land uses, had the largest impacts assessed, of all peri-UA land uses. European NPK mineral fertilizer production to cover N demand of these crops drives all impacts. For fruit crops, on-site N emissions drive marine eutrophication impacts and for irrigated herbaceous crops, phosphate runoff drives freshwater eutrophication impacts. Geographic variability of peri-UA metabolic flows and impacts was displayed. Management practices at the plots, which are linked the land use, are responsible for impacts variability. Regionalization of eutrophication impacts highlights the importance of accounting for the biophysical aspects at the geographic scale at which peri-UA takes place, which is a much finer scale than those implemented in current regionalization of impact assessment methods in LCA. This study provides a fundamental baseline needed to assess transition scenarios of peri-UA at an appropriate geographic level of analysis and gives essential knowledge to guide appropriate circular and sustainability strategies for the sector.

A review on urban agriculture: technology, socio-economy, and policy

It has been a challenge to support the expansion of urban agriculture (UA) in cities due to its poor economic profitability. However, it is also hard to deny the increasing benefits of UA in improving the socio-environmental dimension of cities. Hence, in this review, different aspects of UA were examined to highlight its value beyond profitability such as social, health and well-being, disaster risk reduction, and environmental perspectives. A case study and relevant policies were analyzed to determine how policy makers can bridge the gap between current and future UA practices and sustainable development. Bridging these policy gaps can help the UA sector to sustainably grow and become successfully integrated in cities. Moreover, advancements in UA technologies and plant biotechnology were presented as potential solutions in increasing the future profitability of commercial UA. Consequently, as new UA-related technologies evolve, the multidisciplinary nature of UA and its changing identity from agriculture to digital technology, similarly require adaptive policies. These policies should maximize the potential of UA in contributing to resiliency and sustainability and incentivize the organic integration of UA in cities, while equally serving social justice.

Exploring connections between pollinator health and human health

Despite recent advances in understanding the role of biodiversity in ecosystem-service provision, the links between the health of ecosystem-service providers and human health remain more uncertain. During the past decade, an increasing number of studies have argued for the positive impacts of healthy pollinator communities (defined as functionally and genetically diverse species assemblages that are sustained over time) on human health. Here, we begin with a systematic review of these impacts, finding only two studies that concomitantly quantified aspects of pollinator health and human health. Next, we identify relevant research relating to four pathways linking pollinator health and human health: nutrition, medicine provisioning, mental health and environmental quality. These benefits are obtained through improved pollination of nutritious crops and an estimated approximately 28 000 animal-pollinated medicinal plants; the provisioning of pollinator-derived products such as honey; the maintenance of green spaces and biocultural landscapes that improve mental health; and cleaner air, water and food resulting from pollinator-centred initiatives to reduce agrochemical use. We suggest that pollinator diversity could be a proxy for the benefits that landscapes provide to human health. This article is part of the theme issue 'Natural processes influencing pollinator health: from chemistry to landscapes'.

Estimating the Water and Carbon Footprints of Growing Avocados in the Munich Metropolitan Region Using Waste Heat as a Water-Energy-Food Nexus Potential

Avocados, which have been labeled a superfood and are very popular around the world, are often grown in areas with water scarcity and have long-distance transports to their end consumer. Water and carbon footprints could be reduced by using greenhouse farming, waste heat and rainwater. This study aims to determine whether avocados and other exotic fruits could be locally or regionally grown in greenhouse systems in Bavaria heated using waste heat and examines whether this approach decreases the resulting water and carbon footprints. To test these hypotheses, the waste heat potential is estimated by analyzing a database provided by the Bavarian Environment Agency. Data on water and carbon footprints are extracted from databases by The Water Footprint Network and FAOSTAT. As a local case study, a greenhouse system using waste heat of a nearby glass factory in Upper Franconia is considered. The results show a tremendous waste heat potential for Bavaria and Munich with reduced carbon, but similar water footprints compared to international avocado production. The required area for these avocado farms would only amount to 0.016% of Bavaria's or 0.02% of Munich's total area. With more uncomplicated handling and earlier fruit bearing, fruits like papaya, guava, or carambola seem to be better suited for greenhouse farming than avocados. Waste heat supported farming in controlled environments can require significantly less water through modern irrigation techniques and should be considered when designing new food security concepts for urban or rural areas.

An Overview of Soil and Soilless Cultivation Techniques—Chances, Challenges and the Neglected Question of Sustainability

Resources such as fertile soil and clean water are already limited in many parts of the world. Additionally, the conventional use of arable land is becoming increasingly difficult, which is further exacerbated by climate change. Soilless cultivation systems do not only offer the opportunity to save water and cultivate without soil but also the chance to open up urban areas such as residential rooftops for food production in close proximity to consumers. In this review, applications of soilless farming systems are identified and compared to conventional agriculture. Furthermore, aspects of economic viability, sustainability and current developments are investigated. An insight into the most important soilless farming systems—hydroponics, aquaponics and vertical farming—is provided. The systems are then differentiated from each other and, as far as possible, evaluated in terms of their environmental impact and compared with conventional cultivation methods. Comparing published data analyzing the yield of hydroponic cultivation systems in comparison to soil-based cultivation methods enables a basic overview of the profitability of both methods and, thus, lays the foundation for future research and practical applications. The most important inert substrates for hydroponic applications are presented, and their degree of sustainability is compared in order to emphasize environmental impacts and affect substrate selections of future projects. Based on an assessment of the most important soilless cultivation systems, the challenges and developments of current techniques are highlighted and discussed.

Estimating the Potential of Building Integration and Regional Synergies to Improve the Environmental Performance of Urban Vertical Farming

Vertical farms have expanded rapidly in urban areas to support food system resilience. However, many of these systems source a substantial share of their material and energy requirements outside their urban environments. As urban areas produce significant shares of residual material and energy streams, there is considerable potential to explore the utilization of these streams for urban agriculture in addition to the possibility of employing underutilized urban spaces in residential and commercial buildings. This study aims to explore and assess the potential for developing more circular vertical farming systems which integrate with buildings and utilize residual material and energy streams. We focus on the symbiotic development of a hypothetical urban farm located in the basement of a residential building in Stockholm. Life cycle assessment is used to quantify the environmental performance of synergies related to energy integration and circular material use. Energy-related scenarios include the integration of the farm's waste heat with the host building's heating system and the utilization of solar PV. Circular material synergies include growing media and fertilizers based on residual materials from a local brewery and biogas plant. Finally, a local pick-up system is studied to reduce transportation. The results point to large benefits from integrating the urban farm with the building energy system, reducing the vertical farm's GHG emissions up to 40%. Synergies with the brewery also result in GHG emissions reductions of roughly 20%. No significant change in the environmental impacts was found from the use of solar energy, while the local pick-up system reduces environmental impacts from logistics, although this does not substantially lower the overall environmental impacts. However, there are some trade-offs where scenarios with added infrastructure can also increase material and water resource depletion. The results from the synergies reviewed suggest that proximity and host-building synergies can improve the material and energy efficiency of urban vertical farms. The results provide insights to residential building owners on the benefits of employing residual space for urban food provisioning and knowledge to expand the use of vertical farming and circular economy principles in an urban context.

Challenges and Sustainability Dynamics of Urban Agriculture in the Savannah Ecological Zone of Ghana: A Study of Bolgatanga Municipality

Increasingly, urban land use planning is getting more complex as limited urban spaces are continuously allocated among diverse land uses. From previous urban food system studies in Ghana, it has become apparent that large portions of urban land parcels are unsustainably converted to urban infrastructure. Hence, the sustainability of the food system is significantly threatened by inefficient spatial and infrastructure planning mechanisms that fail to protect urban agricultural zones. Of critical concern is the fact that agricultural land use allocations on planning schemes are easily converted to residential uses under demand driven expropriations. In that respect, this study was undertaken in the Bolgatanga Township to understand how urban dwellers sustain urban agricultural practices within the city. Using field surveys, key informant interviews and GIS mapping, the study found that, the total sizes of agricultural lands have decreased significantly since 1996 as urban Bolgatanga began sprawling from the inner city through to the urban fringes. In the process, agricultural lands have decreased in terms of both size and contiguity at the household level, compelling farmers to create multiple segregated farmlands within residential neighborhoods in the form of compound farms or fenced urban gardens. Hence, some urban farmers continue to rely on undeveloped residential plots and open public spaces in the inner city for production, but they easily lose these as developments in residential neighborhoods intensifies. From the physical development pattern of the city, we conclude that urbanization in agrarian cities will exacerbate the challenges of food production if relevant policy interventions are unavailable to provide for and protect agricultural lands. The study recommends that, food-inclusive planning schemes should be the basis of future physical plans to guide land uses in the peri-urban and rural zones. This will require both political will and community consensus building on the necessity to preserve urban agricultural space to sustain food supply.

Spatiotemporal dynamics of soil health in urban agriculture

There is a paucity of data on the state of urban agriculture soils. In order to develop efficient management practices, it is necessary to understand the seasonal dynamics of the soil health of these systems. This study sampled two community gardens, and one commercial urban agriculture site on a monthly basis over the span of one year. The dynamic analysis examined soil nutritional, chemical and microbial properties. Plant biodiversity was significantly higher in community gardens compared to commercial sites. Analysis of soil nutrients revealed fluctuations of mineral nitrogen with seasonal conditions and consistently high concentrations of plant-available phosphorus. We identified gradually decreasing soil total nitrogen and carbon concentrations throughout the year. Soils were abundant in arbuscular mycorrhizal fungi spores. Soil metabarcoding using 16S and ITS amplicons revealed a seasonal gradient of the microbial diversity and changes after the application of organic fertilizer. Soil-borne potential human pathogens were also detected in the soils. The results of this study provide relevant information about soil management principles in urban agriculture systems. These principles include mulching and the use of nutrient-balanced composts to counteract decreasing carbon pools and the excessive accumulation of phosphorus.

Sustainability of Vertical Farming in Comparison with Conventional Farming: A Case Study in Miyagi Prefecture, Japan, on Nitrogen and Phosphorus Footprint

The reduced requirement for nutrients in vertical farming (VF) implies that the potential for lower environmental impact is greater in VF than in conventional farming. In this study, the environmental impacts of VF were evaluated based on a case study of VF for vegetables in Miyagi Prefecture in Japan, where VF has been utilized in post-disaster relief operations in the wake of the 2011 Great East Japan Earthquake. The nitrogen (N) and phosphorus (P) footprints of these VFs were determined and analyzed to quantify the potential reduction in N and P emissions. First, the N and P footprints in conventional farming were calculated. Then, those footprints were compared with three different scenarios with different ratios for food imports, which equate to different levels of food self-sufficiency. The results show a decrease in the N and P footprints with increased prefectural self-sufficiency due to the introduction of VF. In addition to reducing the risks to food supply by reducing the dependence on imports and the environmental impacts of agriculture, further analysis reveals that VF is suitable for use in many scenarios around the world to reliably provide food to local communities. Its low vulnerability to natural disasters makes VF well suited to places most at risk from climate change anomalies.

Evaluation of commercial composts and potting mixes and their ability to support arbuscular mycorrhizal fungi with maize (Zea mays) as host plant

The use of composts and potting mixes in food production systems is a promising way to counteract the effects of soil degradation and allows crop growth in soilless culture systems. Arbuscular mycorrhizal fungi (AMF) are a well-studied group of beneficial plant symbionts that have been shown to provide important ecosystem services. This study analysed the properties of nine commercial Australian potting mixes and composts and investigated whether they support colonization of maize plants with AMF in a plant growth bioassay. Physicochemical analyses showed highly variable properties between the substrates, with some extreme values that limited plant growth. DNA-based analysis revealed the presence of various plant pathogens, which was linked to inhibited plant growth in one substrate. Some substrates did not meet national quality standards, due to the concentrations of plant nutrients, heavy metals, or substrate maturity. Plant growth was mostly limited due to nitrogen immobilization, which required weekly fertilizer applications. Solid state ¹³C nuclear magnetic resonance spectroscopy gave insight into the decomposition state of the substrates. Plant roots in most substrates were well colonized with AMF (>60% root length), regardless of most substrate properties. Root colonization was negatively affected in only one substrate, likely due to ammonium toxicity. Results of this study show that not all commercial substrates adhered to national quality standards. Potting mixes and composts can support high mycorrhizal root colonization when plant growth is otherwise not limited.

Potential Key Factors, Policies, and Barriers for Rooftop Agriculture in EU Cities: Barcelona, Berlin, Bologna, and Paris

The main objective of this study is to contribute a framework and to provide an overview of potential key factors, policies, and barriers associated with the integration of rooftop urban agriculture (RUA), building on stakeholders' perspectives in four European cities (Barcelona, Berlin, Bologna, and Paris). The research was developed in two phases, namely, a workshop and a survey of stakeholders involved in RUA from the four cities. Education, environmental, research, technological innovation, food production, and social factors play an important role in implementing RUA. Productive spaces, cultural values, social cohesion, social rural-urban links, and the high cost of urban land are highlighted as factors that “promote” RUA. In contrast, the cost of water and pollution are major contextual factors that constrain RUA. Policies related to food trade and urban planning are those that most limit RUA development. Major architectural and technical barriers related to the limits on building heights, historical buildings, a lack of specific building codes, building design and roof accessibility were identified. The high cost of infrastructure and policies that prohibit RUA product sales emerged as economic constraints. Major differences among the cities studied included the perceived effect of urban policies on RUA diffusion as well as the perceived relevance of economic and pollution factors. This study revealed that extensive dissemination and the development of appropriate information about RUA are needed. The creation of new regulations, as well as modifications to urban and building codes to support RUA, is also envisaged. This approach will consider a more flexible land-use policy that allows agriculture to take place in cities as well as marketing frameworks for RUA products. For future studies, it would be useful to apply the framework developed in this study to a larger sample. A study is also needed to confirm hypothetical differences between cities.

Promoting Urban Agriculture and Its Opportunities and Challenges—A Global Review

Multifunctionality of urban agriculture can support the resolve of many urban challenges. Therefore, it is vital to understand the contribution of academic studies on urban agriculture practices as scientific information. The present study followed a systematic literature review based on the PRISMA method. Finally, 54 identified articles were analyzed. The review study mainly examined the contribution of academic literature on urban agriculture under four dimensions: the socio-economic context of the country, type of agriculture model, opportunities, and challenges. The results revealed the focus of academic literature on urban agriculture to show favoritism toward developed countries’ community gardens. Moreover, the leading academic focus on this discipline identifies multifunctionality. People’s motivations in developed countries tend to favor social, health-related, and educational benefits of urban agriculture; however, in developing countries, urban agriculture is more related to economic and ecological needs. Challenges for urban agriculture are also different among developed and developing countries. Nevertheless, existing academic studies have given comparatively less attention to identifying challenges, benefit groups of urban agriculture, and government support. Since urban agriculture is highly reliant on local factors, studying more about opportunities and challenges for urban agriculture under different socio-economic contexts and different agriculture models could be more beneficial to connect farming practices in cities with urban planning. Therefore, to make an adequate academic contribution to urban sustainability, future urban agriculture studies need to be more holistic.

Reviewing chemical and biological risks in urban agriculture: A comprehensive framework for a food safety assessment of city region food systems

Attention to urban agriculture (UA) has recently grown among practitioners, scientists, and the public, resulting in several initiatives worldwide. Despite the positive perception of modern UA and locally grown, fresh produce, the potential food safety risks connected to these practices may be underestimated, leading to regulatory gaps. Thus, there is a need for assessment tools to evaluate the food safety risks connected to specific UA initiatives, to assist practitioners in self-evaluation and control, and to provide policy makers and scholars a means to pursue and assess food safety in city regions, avoiding either a lack or an excess of regulation that could ultimately hinder the sector. To address this aim, this paper reviews the most recent and relevant literature on UA food safety assessments. Food safety indicators were identified first. Then, a food safety assessment framework for UA initiatives was developed. The framework uses business surveys and food analyses (if available) as a data source for calculating a food safety index for single UA businesses and the whole UA landscape of a given city region. The proposed framework was designed to allow its integration into the CRFS (City Region Food System) toolkit developed by FAO (Food and Agriculture Organization of the United Nations), RUAF foundation (Resource Centres on Urban Agriculture and Food Security) and Wilfrid Laurier University.

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Connection of several biological and chemical food safety risks to UA techniques.

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Identifiable food safety risk factors for diverse UA practices.

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Framework for the assessment of food safety levels of UA initiatives.

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Development of a risk-based assessment that can be integrated into the FAO CRFS framework.

Ecosystem Services of Urban Agriculture: Perceptions of Project Leaders, Stakeholders and the General Public

Within the scholarly debate, Urban Agriculture (UA) has been widely acknowledged to provide diverse environmental and socio-cultural ecosystem services (ESs) for cities. However, the question of whether these potential benefits are also recognized as such by the involved societal groups on the ground has not yet been investigated. This paper aims at (1) assessing the perceived ESs of UA, comparing the views of different societal groups in the city of Bologna, Italy (namely: UA project leaders, stakeholders and the general public) and (2) to identify differences in the evaluation of specific UA types (indoor farming, high-tech greenhouses, peri-urban farms, community-supported agriculture, community rooftop garden and urban co-op). In total, 406 individuals evaluated 25 ESs via a standardized Likert-scale survey. The study unveiled similarities and divergences of perceptions among the different societal groups. The statistical analysis indicated that the general public and UA stakeholders agree on the high relevance of socio-cultural ESs, while provisioning ESs was considered as less significant. UA types focusing on social innovation were expected to provide higher socio-cultural ESs whereas peri-urban activities were more closely linked to habitat ESs. We assume that involvement and knowledge of UA are determining factors for valuing the provision of ESs through UA, which needs to be considered for ES valuation, particularly in a policymaking context.