Designer Cropping Systems for Polluted Land

By Vimal Chandra Pandey, Gordana Gajic, Manhattan Lebrun and Pooja Mahajan

Designer Cropping Systems for Polluted Land explores the processes and techniques of making polluted land safe for planting edible and non-edible crops. The book provides readers and practitioners with a comprehensive understanding of contaminated land use through designer cropping systems. It seeks to present promising and affordable practices for transforming polluted lands while also providing an excellent basis from which scientific knowledge can grow and widen in the fields of phytoremediation-based biofortification.

• Provides basic understanding on how to produce edible crops on polluted lands with biofortification
• Explores cropping systems for the extraction of metals for industrial use
• Discovers the role of designer cropping systems in phytoremediation programs

• Language: English
• Publisher: Elsevier Science
• Release date: Oct 20, 2023
• ISBN: 9780323956192

Vimal Chandra Pandey

Dr. Vimal Chandra Pandey is an applied research scientist internationally recognized for his research in the area of Phytomanagement of polluted sites. He is listed as the World's Top 2% Scientists, announced by Stanford University, California, United States, and published by Elsevier BV, 2020, 2021, 2022, and 2023. Dr. Pandey's research focuses mainly on the remediation and management of heavy metal-polluted lands and post-industrial lands, using ecologically and socio-economically valuable plants, to regain ecosystem services and support a bio-based economy as phytoproducts. His research interests also lie in fostering phytoremediation for utilizing polluted lands and thereby attaining the United Nations Sustainable Development Goals. Dr. Pandey's phytoremediation work has led to the extension of phytoremediation beyond its traditional application. He is now engaged in exploring commercial phytoremediation with the least risk, minimum input, and low maintenance for the rehabilitation and revegetation of fly ash dumpsite, red mud dumpsite, coal-mined sites, etc. Dr. Pandey worked at CSIR-National Botanical Research Institute, Babasaheb Bhimrao Ambedkar University, and the Council of Science and Technology, Uttar Pradesh (CSTUP), Lucknow, India. He is the recipient of several awards/honors/fellowships. Dr. Pandey is a member of the IUCN Commission on Ecosystem Management and the National Academy of Sciences, India. Dr. Pandey has published over 114 scientific articles/book chapters in peer-reviewed journals/books. He is also the author and editor of several books published by Elsevier, Springer, Wiley, and CRC Press, with several more forthcoming. Dr. Pandey is Associate Editor/Editor/Academic Editor/Board Member of journals such as Land Degradation and Development; Restoration Ecology; Ecological Processes; Environment, Development, and Sustainability; Ambio; Environmental Management; Discover Sustainability; Bulletin of Environmental Contamination and Toxicology; and PLOS ONE by Wiley/Springer/PLOS. He also worked as a guest editor for many reputed international journals.

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The agricultural extensification on polluted lands

Contents

1.1 Introduction 1

1.2 Increasing polluted lands over the world 5

1.3 Need for agricultural extensification on polluted lands 10

1.4 Global food security is a current need for the rapidly growing population 15

1.5 Agricultural extensification for a sustainable food system 18

1.5.1 Soil testing 19

1.5.2 Soil remediation 20

1.5.3 Plant selection and management strategies 39

1.6 Regular monitoring, quality, and quantity assessment of produced food from polluted lands 47

1.7 Consideration of legal, ethical, and consumer-acceptability aspects 55

1.8 Conclusion and future prospects 59

References 61

1.1 Introduction

The phrase When soils fail, civilizations fall was first used by US President Franklin D. Roosevelt in response to the distress of the American Dust Bowl, which destroyed large areas in the Midwest United States in 1937. This phrase is still relevant today and serves as a stern warning to secure our important food, water, and other environmental services. The land is an essential resource because it sustains global biogeochemical cycles and regional food webs. Moreover, land resources serve a variety of other human desires beyond agricultural output. The need for land for the production of food, fiber, feed, and fuel is rising dramatically along with the population. By the year 2100, there will likely be 11.2 billion people on earth (UNDESA, 2017). A population explosion of this magnitude will result in a massive need for the production of food, fiber, and feed. However, more than 33% of arable areas are no longer fit for farming due to degradation caused by several anthropogenic activities. For instance, a variety of agrochemicals will have to be used extensively to provide food since changing climatic circumstances will hasten the spread of different plant diseases.

Additionally, the terrestrial ecosystem serves as a major pollution sink (Walker et al., 2021). Hence, the problem of increasing food production in a sustainable way for a population that is expanding quickly may be one of the biggest challenges (Notarnicola et al., 2012). The use of land for agriculture will compete with its use for habitation, infrastructure, and industry since land is a scarce resource. Any modifications to existing patterns of land utilization will influence the resilience of socioeconomic and ecological systems (Schirpke et al., 2017). Due to this, it is difficult to expand agricultural output without also using more arable land (Godfray and Garnett, 2014). However, it is not sustainable to engage in agricultural extensification in new areas at the expense of wetlands, grasslands, and forests since it would hasten the loss of biodiversity and other environmental problems. Polluted soils, however, might be used safely for agricultural production by implementing cautious scientific and technical intrusions (Abhilash et al., 2016). Consequently, the need for arable land will unavoidably force us to use polluted lands as an economic boon for agricultural and environmental sustainability.

Due to growing industrial, agricultural, and civic activity, the land is being significantly damaged on a global scale. Multiple soil functions can be harmed as a result of land degradation, which can also contaminate surface and groundwater. The direct application of pesticides, sewage sludge, fertilizers, and manure, which frequently include a significant amount of inorganic and organic pollutants, may be the cause of soil pollution. Localized polluted soils, often known as brownfields today, are usually linked to decommissioned industrial facilities, unintentional pollution releases, or improper municipal and industrial waste disposal (Grimski and Ferber, 2001). According to Ahmad et al. (2018), in the United States alone, there are about 500,000 brownfield sites that need to be repaired. According to the National Round Table on the Environment and Economy of Canada, there are over 30,000 such sites in Canada (Nissim and Labrecque, 2021).

Several organic as well as inorganic pollutants are responsible for soil contamination as classified in Fig. 1.1.

Figure 1.1 A comprehensive classification of soil pollutants ( Rodríguez-Eugenio et al., 2018).

Heavy metals are among the many organic and inorganic contaminants that cause widespread worry about contaminated soil. More than 37% of cases of pollution in the European Union are caused by metals, followed by mineral oil (33.7%), polycyclic aromatic hydrocarbons (PAHs) (13.3%), and other substances (Pandey et al., 2016). Remediation of these urban brownfields (polluted lands) is seen as a useful alternative to urban sprawl in many nations due to its social, economic, and environmental benefits. Moreover, brownfield exposure has been linked to severe health problems for locals if not treated properly and has had detrimental effects on public health in many major cities in Europe, the United States, India, and China (Dair and Williams, 2006; Hota and Behera, 2015; Li and Ji, 2017; Nissim and Labrecque, 2021). Excavation is the most popular ex-situ technique for the restoration of polluted lands, and it entails soil removal followed by transportation to a landfill or an approved treatment facility (Kuppusamy et al., 2016; Reddy et al., 1999). However, on-site cleanup methods are now more appealing to consider due to rising operational costs, stricter rules at dumping sites, and the introduction of new treatment technology. These include several highly engineered techniques (such as soil, flushing, soil vapor extraction, electrokinetics, soil heating, soil stabilization, soil solidification, and bioremediation). Bioremediation approaches have nature-based solutions and high environmental footprints because they consume chemical reagents and fossil fuel-based energy supplies, and which provide numerous environmental, social, and economic advantages over conventional approaches (Arora, 2018; Kuppusamy et al., 2017; Megharaj and Naidu, 2017; Ojha et al., 2022; Song et al., 2019; Verma and Kuila, 2019; Vidali, 2001).

Phytoremediation, a low-cost alternative method powered by solar energy and carried out in situ, employs plants to absorb metals (Mahajan and Kaushal, 2018; Pandey and Bajpai, 2019; Yan et al., 2020). Due to their distinct nature and physical characteristics—such as low concentrations and uneven distribution of pollutants restricted to superficial soil layers—polluted areas are often seen as having significant potential for rehabilitation with the introduction of in-situ green technology. In situations of low pollution, phytoremediation may help in stabilizing or eliminating contaminants without the need for technological intervention. However, the phytoremediation process is site-specific and contaminant-specific and may need technological intervention for the complete remediation of polluted sites (Mohanty, 2021; Pandey and Bajpai, 2019; Singh et al., 2015).

In the 1990s, the first successful phytoremediation programs were launched as an accessible and cost-effective replacement of conventional physio-chemical remediation techniques to address water and soil pollutants (Pilon-Smits, 2005; Schwitzguébel et al., 2002). The technology does have some drawbacks, though, such as the lengthy time it takes to lower soil pollution levels below acceptable levels. Research indicates that a conservative estimate for the duration of phytoremediation of soil would be many years to centuries, although the timeframe depends on the targeted contaminant(s), the adopted strategy, and the plant(s) used (Cunningham and Ow, 1996; Gill et al., 2016).

In case phytoremediation proves to be effective, it could potentially contribute towards the accomplishment of different UN SDGs (Sustainable Development Goals). These include (1) 3rd SDG-reducing the possibility of pollution-related health hazards for local communities, (2) 9th SDG-establishing the necessary local infrastructure for the project, (3) 13th SDG-mitigating CO2 emissions by reducing energy consumption for decontamination, and (4) 14th and 15th SDG-minimizing contamination of both aquatic and terrestrial ecosystems (Kaushal et al., 2021; Nissim and Labrecque, 2021; Pronoza, 2017; Upadhya et al., 2020). Aside from fulfilling the growing need for food of rapidly expanding populations, utilizing contaminated lands for agriculture could also aid in revitalizing such deteriorated lands for effective usage instead of allowing them to remain unproductive and unused (Jasrotia and Pandey, 2023). To meet the increasing requirement for energy, it is also possible to combine agricultural production on polluted lands with the growth of biofuel and biomass crops as well as biofortification initiatives (Pandey and Souza-Alonso, 2019; Pandey et al., 2015; Randelović and Pandey, 2023; Zhao and McGrath, 2009). However, crop cultivation on polluted lands raises several ecological, financial, and social issues that need to be fully addressed.

1.2 Increasing polluted lands over the world

Globally, land pollution caused by human activities is a pervasive issue. The legacy of polluted lands worldwide is due to industrialization, war, mining, and intensification in agriculture (Broomandi et al., 2020; de Graaff et al., 2019; Mohsin et al., 2021; Prăvălie, 2021; Qin et al., 2021; Rawtani et al., 2022). Since the growth of metropolitan regions, solid and liquid wastes have been dumped into the ground as a disposal method (Clapp, 2002). It was believed that the toxins would miraculously vanish after being buried and hidden from view, posing no damage to the environment or human health. The problem of soil contamination is grave (Swartjes, 2011). Although most of the pollutants are the result of human activity, certain contaminants may be found naturally in soils as parts of minerals and are dangerous in high amounts (Havugimana et al., 2017). Land pollution can be diffuse or local. Human activity and emissions from distant sources cause diffuse land contamination, whereas substantial industrial activity, mining, military activities, inadequate waste management, or accidents cause local land pollution (Cachada et al., 2018). Before the transfer of pollutants to the soil, emission, transformation, and dilution of contaminants in other media result in diffuse pollution (Barsova et al., 2019). The three most significant channels for the access of dispersed contaminants into the soil are air deposition, agriculture, and flooding (Campbell et al., 2005). In rare situations, these mechanisms can also produce local pollution. In general, persistent organic pollutants, inorganic contaminants such as heavy metals, excessive fertilizer, pesticide applications, etc. are among the primary causes of diffuse contamination. Moreover, agrochemical and industrial advancements are continually changing the variety of pollutants in the soil (Maximillian et al., 2019).

The consequences of soil contamination depend on the qualities of the soil, which affect the bioavailability, mobility, residence time, and pollutant concentrations. Soils can retain, immobilize, and degrade contaminants, so the direct consequences may take time to appear (Arias-Estévez et al., 2008; Cipullo et al., 2018; Koptsik and Koptsik, 2022; Nkoh et al., 2022). Inorganic contaminants, such as metallic trace metals and radionuclides, and organic contaminants, such as antibiotics and hormones, can harm ecosystems and human health (Kafle et al., 2022; Srivastava et al., 2019; Thakare et al., 2021; Urra et al., 2019; Zamora-Ledezma et al., 2021).

Local soil pollution management involves surveys to identify potentially polluted areas, site investigations to figure out the level of contamination and its environmental implications, and corrective and aftercare procedures. However, diffuse soil contamination is more challenging to manage, as it may cover vast regions and not be immediately apparent (Chon et al., 2012; Swartjes et al., 2012). Although many industrialized nations have conducted long-term soil surveys, there is no true extent of diffuse soil pollution and standardized soil monitoring system remains unknown. Identifying pollutants is difficult and expensive, given the various metabolites formed by soil microorganisms (Girotti et al., 2008; Raimi et al., 2022), making the link between the extent of soil contamination and the pollutant source unclear.

According to the Status of the World's Soil Resources Report, some contaminants can also cause soil acidification and nutrient imbalances, which are significant issues worldwide (FAO and ITPS, 2015). Land pollution mostly results from industrial operations, which vary between nations depending on the allowed contamination levels of the industries (Alloway, 2013; Zwolak et al., 2019). Examples of polluting activities include power plants, waste treatment, smelters, production facilities (heavy metals and chemicals), gas manufacturing, landfills, oil processing, use of fertilizers and pesticides, timber treatment, military actions, airports, and laboratories in developed countries such as Europe, the United States, Australia, and China (Artiola et al., 2019; Delang, 2017; Panagos et al., 2013; Tiller, 1992). For instance, the US army has polluted 1.2 million tons of soil with explosives, and the effects of explosive pollution on other nations' environments are also significant (Kuppusamy et al., 2017; Pichtel, 2012). In developing nations such as India, South Korea, Japan, etc. examples of potentially contaminating activities include mining, oil and gas extraction, agricultural practices, industrial accidents, nuclear waste disposal, etc. (Hou et al., 2020; Lee et al., 2019; Minh et al., 2006; Saha et al., 2017; Tokunaga, 1996).

The most prominent pollutants are shared by developed and developing nations due to similarities between the major forms of polluting industrial operations. This indicates that the most common pollutants in the United States and Canada are dioxins, furans, benzene, arsenic, cadmium, lead, mercury, PAHs, and PCBs (polychlorinated biphenyls) (Jackson, 2009). Similarly, in Australia, the primary pollutants include hexavalent chromium, tri- and tetrachloroethylene, dioxins, lead, arsenic, cadmium, and petroleum hydrocarbons, while cyanides, phenols, PAHs, and heavy metals are the most prevalent contaminant in Europe (Bollag et al., 1999;Knox et al., 1999; Panagos et al., 2013; Telesiński and Kiepas-Kokot, 2021). In developing nations, the major pollutants are As, Cd, Cr, Pb, Hg, radionuclides, and other pollutants such as cyanide, fluorides, dioxins, PCBs, PAHs, and pesticides (Kuppusamy et al., 2017; Mahajan and Kaushal, 2018). Cadmium, in particular, is the most prevalent pollutant found in India (Srinivasa and Govil, 2008). Similarly, common pollutants in certain emerging countries include radionuclides in Central and Southeast Asia, arsenic in China, India, and South America, pesticides in India, Central, and South America, Cr in South America, China, and India (Brandon, 2012; Gunnell et al., 2007; Musah et al., 2021; Shaji et al., 2021; Singh and Ward, 2009; Yang et al., 2018a).

When contaminated areas are adjacent to structures and people, close to water sources, and significant ecosystems, they become a more pressing concern. Polluted land can induce harmful impacts on plants, which can impede or restrict growth, as well as on vertebrates and invertebrates. It can also pollute water sources, infiltrate the food chain, be consumed, breathed, or come into contact with the skin, and result in explosions or fires (Edwards, 2002). The impacts of pollutants on human health depend on the kind of contaminant, the degree of exposure, and the susceptibility of the afflicted person. Possible health consequences include neurological diseases, risk of cancer, physical and mental illnesses, weak immunity, organ failure, and shortened life expectancy (Khan et al., 2021; Zeng et al., 2019; Zwolak et al., 2019). Additionally, land pollution has significant socioeconomic effects, such as high cleanup costs and reduced market value (Ajibade et al., 2021). Given that the pollutants involved have a long half-life, the remediation strategy is wholly ineffectual, or responsibility for cleanup is challenged because the appropriate authorities lack the money to carry out remediation, the effects of site contamination may endure for a long time (Sharma et al., 2022). It is challenging to precisely quantify both the actual percentage of the world's landmass that is likely to be currently affected and the cost of their remediation because many nations have not yet carried out a comprehensive and organized national study on the identification and evaluation of hazardous sites.

The United Nations Environment Programme (UNEP) and International Soil Reference and Information Centre (ISRIC) conducted the first-ever worldwide estimate of soil contamination in the 1990s, estimating that 22 million hectares had been impacted (Oldeman, 1991; Rodríguez-Eugenio et al., 2018). The most recent statistics, however, suggest that this figure could significantly understate the severity and scope of the issue. The majority of national efforts to gauge the severity of soil contamination have been made in wealthy nations. Additionally, there are approximately 1336 contaminated or polluted sites in the USA that are listed on the Superfund National Priorities List (Superfund: National Priorities List (NPL) | EPA) and there are approximately 3 million potentially polluted sites in the European Economic Area (Contamination from local sources—European Environment Agency (europa.eu)). Nearly 700 coastal locations in Brazil are declared polluted by Brazil's environmental protection agency Ibama (Soares et al., 2022). Little data is available on early estimates of the percentage of land damaged, and Chile, Mexico, and Latin America are already creating a national inventory of possibly contaminated locations. In Latin America, about 50,000 tons of pesticide waste need to be cleaned up, yet the precise location of these sites is unknown (Raimi et al., 2022).

Approximately 45% of the estimated 2.5 million potentially contaminated sites in Europe have been found thus far, of which 340,000 are believed to be genuinely poisoned and only 15% of them have undergone remediation (Panagos et al., 2013; van Liedekerke et al., 2014). Nearly 9000 possibly hazardous sites have been identified in British Columbia alone (Kuppusamy et al., 2017). Despite varying patterns across Europe, it is evident that the rehabilitation of polluted sites remains a substantial task. The two most significant sources of soil pollution in Europe are waste disposal and industrial operations. Heavy metals and mineral oils are the most prevalent pollutants (Panagos et al., 2013). There are a total of 12,723 contaminated soil locations in Canada, including 1699 sites with surface soil pollution from metals, petroleum hydrocarbons, and PAHs (Tripathi et al., 2019a). In Australia, there were 60,000–200,000 sites that may be polluted. Five hundred fifty nine high-risk locations have been identified in New Zealand and call for corrective action (Kuppusamy et al., 2017).

Land contamination has been caused by mainly waste disposal, mining, oil, and pesticide spills in African countries (Fayiga et al., 2018). More than 7000 spills were recorded by the federal government of Nigeria during the years 1970 and 2000 and this soil pollution is linked to the extraction of oil and the use of heavy mining equipment especially in the Near East and North Africa regions (Fayiga et al., 2018; Obike et al., 2020). The use of tainted groundwater or wastewater for irrigation on agricultural land is a typical cause of soil contamination. Many locations across Africa are polluted by PCBs, with Malawi having the most affected sites approximately 211 as of the year 2005 (Debela et al., 2022).

Trace element contamination is a major issue for polluted sites in Asian countries, posing a threat to human health and the future of food production in polluted regions. Urban regions in China are responsible for polluting around 10% of agricultural farms (Lam et al., 2013; Sun et al., 2019). 16% of all Chinese urban soils and 19% of their agricultural soils, according to the Chinese Environmental Protection Ministry, are classified as contaminated (Cheng et al., 2019). Most of the survey sites are found to be polluted with inorganic pollutants, especially heavy metals (Cheng, 2003; Li et al., 2019; Wei and Yang, 2010). According to Yang et al. (2018a), 1041 agricultural sites and 402 industrial sites across China are severely affected by Cd, Pb, and As pollution. Cd is one of the most significant pollutants contaminating Chinese agricultural soils due to its high mobility in the soil, except in poorly drained soil, where sulfides are abundant (Khanam et al., 2020; Wang et al., 2019). Arsenic is naturally found in groundwater in many regions of Southeast Asia and agriculture is at risk because of this, especially in rice paddy areas where anaerobic conditions are common (Brammer, 2009; Rahman et al., 2009).

Furthermore, Asia is the region that emits the most anthropogenic Hg into the atmosphere as a result of Hg mining, the chemical industry, and the gold industry (Li et al., 2009). Over 113,000 acres of polluted land are thought to exist in Japan (GJ, 2007). In India 112 confirmed polluted sites and 168 that require further research exist (Brief_Contmainated_sites_in_india.pdf [cpcb.nic.in]). Data on the actual level of pollution are lacking in the majority of South-East European and Central Asian nations. These data highlight the inadequacy of the information that is currently available and the differences in registered contaminated sites across geographical provinces while also being instructive in terms of aiding our understanding of the effects of specific activities on soils. Numerous nations still lack extensive and systematic research on the identification and evaluation of polluted sites, which significantly complicates the task of precise estimation of contaminated regions and the remediation cost (Vilela and de Oliveira, 2021).

Due to a lack of data and information, one of the biggest global issues in low- and middle-income countries remains hidden from the international community (Panagiotakis and Dermatas, 2015). Fortunately, the significance of soil contamination is becoming more widely recognized, which has increased research on soil pollution assessment and its remediation (Fig. 1.2). To protect the health and well-being of people, the FAO (2016) suggested that national governments create legislation against soil pollution and limit the pollutants accumulation beyond of predetermined thresholds. Governments are encouraged to aid in the remediation of contaminated soils that exceed safety standards for both humans and the environment. The global remediation market has grown at a compound annual rate of 5.5% from 2013 to 2019, increasing from approximately US $59.5 billion in 2013 to almost US $80.5 billion in 2019 (Kuppusamy et al., 2017; Vilela and de Oliveira, 2021). Despite ongoing hazardous waste generation and disposal by humans, only a fraction of the estimated potentially polluted sites worldwide have probably been remediated or assessed properly (Vareda et al., 2019). The global rate of site cleanup remains insufficient to protect the environment and public health adequately. Therefore, it is essential to identify and remediate contaminated sites for their potential use.

Figure 1.2 Number of articles published on soil contamination and remediationData fetched from science direct as on December 3, 2022 from www.sciencedirect.com

1.3 Need for agricultural extensification on polluted lands

Agriculture extensification, the expansion of agricultural land use into new areas, is crucial for the restoration of contaminated lands, which often pose significant threats to human health and the environment. This can be achieved through sustainable and responsible land use planning and management practices, which not only remediate contaminated sites but also leads to food security and local economic development (Qin et al., 2021). The need for agriculture extensification on polluted lands is driven by various factors, including the growing demand for food due to increasing population, as well as the impact of industrial and urban development on the environment (Ray and Ray, 2011).

The current annual population change is projected to be approximately 80 million each year, and the global population is now rising at a pace of about 1.13% per year. Governments throughout the world would struggle to satisfy demand given the predicted global population of nearly 9.6 billion people. This has put a huge burden on the agricultural sector must produce more food and fiber to feed a growing population and more feedstocks for a potential bioenergy market. Between 1970 and 1990, the green revolution, increased availability of manufactured ready-prepared meals, targeted expenditures in research and technology, and other factors all contributed to an average 2% annual increase in the worldwide aggregate agricultural production (Tripathi et al., 2019b). It is required for output in the developing world to almost quadruple to meet the demands. This means that there will be a considerable rise in the output of several vital sectors. Food production is mostly dependent on soils (95%) and promotes human health in terms of quantity and nutritional quality (Oliver and Gregory, 2015). The necessary ecosystem services and reliable supply of additional food and fiber can only be provided by healthy soils. The competence of natural processes and resources to deliver products and services that either directly or indirectly fulfill human requirements has drawn a lot of attention to the supply of ecosystem services (De Groot, 1992). The availability, access, usage, and stability of the food supply is the definition of food security. Due to high levels of pollutants, soil contamination affects crop yields, which in turn makes the generated foods unfit for human consumption (FAO and ITPS, 2015). 90% of well-developed mineral soil is made up of minerals, while 10% is made up of bioorganic material. The bio-organic component is made up of humus (70%–90% of it), roots (10%–30%), and an active fraction, which is made up of live soil organisms. However, organic soils built on drained bogs can contain almost entirely organic components in cold, humid climates.

The most significant portion is the topsoil (0–30 cm), which contains the primary turnover mechanisms (Schröder et al., 2018). Its fundamental quality is reliant on the longevity of humus, soil composition, and interactions between organisms. Numerous interrelated factors, such as soil acidity, soil structure, organic matter content, nutrient balance, water retention, etc., affect both soil fertility and production. Healthy microbial activity is crucial for the long-term performance of all these soil activities in agricultural systems. The microorganisms found in the soil, rhizosphere, and plant, collectively known as the soil and plant microbiome, play significant roles in the functioning of ecosystems, plant nutrient uptake, nutrient cycling, and disease inhibition, which eventually control the physiology, health, and performance of plants (Mohammadi et al., 2011). Strong correlations exist between the characteristics of soil and ecosystems with high conservation value, allowing for the promotion and maintenance of vegetation. To enable future sustainable management, proper consideration must be paid to soil restoration and recovery when disturbed, such as by contaminants, subpar farming practices, or overexploitation (Keesstra et al., 2016). If fails to attain sustainable management, then the land will no longer be able to meet the farmer's and the community's economic or ecological expectations. All ecosystems are governed by four fundamental processes: the water cycle, the mineral cycle, the energy flow, and community dynamics. These four processes must all work in harmony for there to be life on earth. The latter is now being examined in particular even though it's yet unclear which part of soil biodiversity is crucial for soil health (Bender et al., 2016). Living things require a water cycle that provides sufficient moisture, and a mineral cycle that provides essential nutrients and efficient energy flow to sustain them. If not, there will be an imbalance in the system. Negligence and bad ecosystem management can alter any one of these processes, which will inevitably affect the others and reduce the system's resilience.

Currently, agricultural fields make up over 48 million km², while only 11 million km² of agricultural land is for food crop production globally (Fig. 1.3). However, from the mid of the 20th century, agricultural intensification has made it considerably simpler to feed the world's rapidly expanding population (agricultural intensification is defined as an increase in crop yield production per unit of area), as opposed to continuing to expand the land area.

Figure 1.3 Global data of total land use.

From 1961 to 2016, cereal production increased by around 400% (0.74 Gt in 1961 to 2.9 Gt in 2016). The trends in the production of fiber globally are similar. This increase in productivity has been accompanied by the Green Revolution, with the use of fertilizers, better cultivars, water, pesticides, and other agronomic approaches (Khush, 2001). However, it should be remembered that during the Green Revolution, environmental effects (such as excessive fertilization and chemical leaching) were mainly disregarded (Gomiero et al., 2011). To attain global food security in the future, it is anticipated that yield increases, rather than area expansion, will continue to account for the majority of the increase in food and fiber production needed. For instance, even if the area utilized to grow wheat is only expected to rise by 1.8% by 2026, yields are predicted to rise by 11% by that time (OECD/FAO, 2017).

Numerous factors can lead to soil contamination, including irrigation with polluted fluids, usage of pesticides, contaminated fertilizers, land-applied waste, releases from mining and refining operations, and direct releases of toxins to soils from industrial processes. Inorganic and organic pollutants (Fig. 1.1) can contaminate soil as a result of these activities. These pollutants can be transferred (and become hazardous) to plants, animals, and people when they are present in the soil. It might be challenging to estimate the degree of soil pollution (Rodríguez-Eugenio et al., 2018). To secure the production of safe food, it is estimated that 137,000 km² of agricultural land in the European Union needs local evaluation and corrective action (Tóth et al., 2016).

Many soil pollutants in Asia are of concern, especially in China, where all soils (16%) and agricultural soils (19%) are thought to be polluted (Kopittke et al., 2019). The relative significance of the different types of pollutants varies globally. Heavy metals (35%), mineral oil (24%), and PAHs (11%) are the three pollutants that are most commonly recorded as contaminants in Europe and contamination mostly results from garbage disposal, commercial and industrial operations (Geeraerts and Belpaire, 2010). All of these pollutants pose a threat to food safety and food security because of their potential to contaminate the food supply chain and alter the functions of soil ecosystems. Take China, for instance, where industrialization and urbanization have caused the average monthly dietary Cd consumption to nearly triple, from 6.9 g kg−1 to 15.3 g kg−1 body weight, from 1990 to 2015, resulting in an average yearly rise of 0.27 g kg−1 body weight (Song et al., 2017).

The Joint FAO/WHO Expert Committee on Food Additives established a provisional tolerable intake value of 25 g kg−1 body weight per month, and the current average intake amount accounts for 61% of that value, yet the rate of growth in Cd consumption is seriously concerning. Associations between contaminated water and soil and cancer villages in important agricultural regions in China have been exposed (Lu et al., 2015). In Bangladesh, rice fields are irrigated with groundwater that has been contaminated with As which results in increasing the amount of As biomagnifications in communities that consume large amounts of rice (Melkonian et al., 2013). Another example is the excessive use of pesticides and herbicides in agriculture to produce an adequate amount of food for the expanding human population (Popp et al., 2013). While the detrimental effects of pesticide usage on soil functions and its biodiversity are well established, however long-term impacts on soil fertility and production are still unknown (FAO and ITPS, 2017). Without a doubt, it is crucial to discover alternate methods of reducing pesticide consumption. Although the wider environmental effects of pesticides are widely known, they are outside the purview of this chapter. Hence, improved regulation is necessary to ensure the proper disposal of these wastes as well as to reduce the creation of contaminated wastes, especially in developing nations. It is also important to locate contaminated areas and clean them up to protect human and environmental health. In addition, expanding agriculture into new areas at the expense of the wetlands, grasslands, and forests is not a sustainable practice since it hastens the decline of biodiversity and contributes to other environmental concerns (Abhilash et al., 2016; Garnett et al.,