Recent Advances in the Remediation of Degraded and Contaminated Soils: A Review of Sustainable and Applied Strategies

Abstract

This review explores the pressing issue of soil degradation and contamination, highlighting their adverse environmental effects and the necessity for sustainable solutions. Soil degradation disrupts ecosystems and accelerates climate change, while soil contamination poses serious health risks to humans and wildlife. Recent advances in mitigation strategies demonstrate promising solutions, focusing on both degradation and contamination. This paper presents innovative methods, including the utilization of a dolomite–sewage sludge mixture to combat soil degradation effectively, enhancing soil fertility and supporting ecosystem restoration. Additionally, it introduces a novel approach using a dolomite–stainless steel slag mixture for petroleum hydrocarbon absorption, showcasing its efficacy in remediating contaminated sites. The results indicate significant improvements in soil health and a reduction in environmental pollutants, underscoring the potential of these mixtures to revolutionize soil management practices. Implementing such strategies not only mitigates degradation and contamination but also contributes to the sustainability of agricultural and natural ecosystems. This article aims to provide a comprehensive overview of these advancements, offering insights for researchers, policymakers, and environmental practitioners striving to foster a healthier and more sustainable environment.

1. Introduction

Soil quality is a term widely referenced in discussions on sustainable agriculture, capturing the overall condition of the soil. It includes various factors that contribute to the soil’s ability to support plant life, regulate water, sustain biodiversity, and act as a buffer against environmental changes. However, there is growing evidence that many agricultural soils are suffering from significant degradation. This degradation is manifesting in various ways, including erosion, loss of organic matter, contamination, compaction, and increased salinity. These issues collectively pose substantial risks to our agricultural systems, highlighting the urgent need for improved soil management practices to ensure soil health and sustainability for future generations [1]. The soil degradation problems can be classified into four categories: biological, chemical, ecological, and physical (Figure 1). Soil degradation manifests in multiple forms: biological, chemical, ecological, and physical—each contributing to the decline in land productivity. Biological degradation is marked by a reduction in microbial activity, often triggered by harmful biochemical reactions in exposed or unprotected soils. This leads to diminished soil fertility and reduced crop yields. Chemical degradation results from excessive use of synthetic fertilizers and pesticides, causing nutrient imbalances, loss of humus, shifts in pH, and a decline in beneficial microbial populations. Ecological degradation, largely driven by climate change, includes altered rainfall patterns, temperature increases, and extreme weather events, all of which reduce land productivity. Deforestation and vegetation loss further accelerate this process by increasing erosion risk and disrupting local ecosystems. Lastly, physical degradation involves the loss of topsoil through floods, runoff, landslides, wind erosion, over-tillage, and the use of heavy machinery. This form of degradation severely impairs soil structure, composition, and long-term fertility [2].

At the global level, the main threats to soil function include the loss of soil organic carbon (SOC), soil erosion, and nutrient imbalances. In Europe, additional concerns such as soil sealing and land take, salinization and sodification, contamination, and changes in SOC are particularly pressing [3]. Soil organic carbon is the largest carbon reservoir in terrestrial ecosystems and a key determinant of critical soil functions, including agricultural productivity. Under stable environmental conditions and long-term, steady-state management, SOC in agricultural soils tends to reach a dynamic equilibrium—balancing carbon inputs (from crop residues and organic fertilizers) with losses from organic matter decomposition [4].

However, decomposition rates of soil organic matter increase more rapidly with temperature than net primary production. As a result, climate-change-driven temperature rises are expected to significantly reduce SOC levels. This trend is especially critical in agricultural soils, where stagnating crop yields in recent decades may already limit carbon inputs, further accelerating SOC depletion [5,6].

Anthropogenic soil erosion has contributed to the long-term degradation of agricultural land, often leading to land abandonment and reduced productivity. While nitrogen and phosphate fertilizers are commonly used to mitigate yield losses, the need to compensate for eroded cropland often drives the conversion of forests and pastures into new farmland, which also requires nutrient enrichment [7,8,9,10]. Moreover, erosion negatively affects the diversity of soil organisms, plants, and animals [11]. The impact of erosion on SOC dynamics depends on specific processes such as detachment and deposition. Research indicates that eroded landscapes contain a smaller total ecosystem carbon pool and that soil organic matter mineralizes more rapidly in sediments than in original topsoil [12]. Climate change exacerbates soil degradation and contamination through a variety of mechanisms, including prolonged droughts, extreme precipitation events, salinization from sea-level rise, and permafrost thawing, each of which alters soil structure, nutrient cycling, and contaminant mobility [13,14,15,16,17]. These stressors compromise the resilience of ecosystems and agricultural productivity, necessitating the development of innovative soil remediation strategies aligned with climate-resilient land management. Soil contamination by heavy metals constitutes a significant global environmental hazard, predominantly arising from anthropogenic activities [18]. Accurately assessing the pollution effects in various areas necessitates data on contamination levels, the mobility of metals, and the key soil properties related to the adsorption and retention of pollutants [19]. The speciation of metals determines the degree of environmental hazard posed by landscape pollution and the migration ability of their compounds [20]. Soil organic matter plays a crucial role in these processes, and studying the relationship between metals and SOM components is essential to evaluate the bioavailability of heavy metals [21]. Salinization and sodification are major processes of soil degradation threatening land productivity and global food security [22]. Salt-induced land degradation is prevalent in arid and semi-arid regions due to insufficient rainfall to sustain the percolation of water through the soil, coupled with irrigation practices that lack adequate drainage systems [23]. The expansion of irrigated agriculture in arid and semi-arid regions has been crucial to meeting the food supply needs of a burgeoning global population. Over the past 50 years, the world’s net cultivated area has increased by 12%, while the global irrigated area has doubled during the same timeframe [24]. Among various degradation processes, land-surface impermeabilization poses the greatest threat to soils as it significantly reduces or eliminates ecosystem functions and services [25]. The processes of land take and soil sealing entail significant reductions in soil function capacities. Consequently, soil subjected to these activities experiences a substantial loss of ecosystem functionalities, many of which are irrecoverable. As a result, land take emerges as a primary contributor to soil degradation, encompassing declines in biodiversity [26], advancing desertification [27], increasing pollutant accumulation [28], and the depletion of productive land [29].

This study highlights the urgent need for developing innovative strategies to improve contaminated and degraded soils. It centers on identifying the major environmental pressures—such as industrial activities, unsustainable agricultural practices, and long-term pollutant accumulation—that compromises soil health and ecosystem services. Through a comprehensive analysis of existing remediation techniques and their limitations, the study aims to explore and propose effective, sustainable approaches to soil rehabilitation. The explicit objectives of this work are as follows:

To synthesize recent scientific advances and technological developments in soil decontamination and degradation mitigation.

To critically assess current remediation methods, identifying their gaps and limitations.

To introduce and discuss two patented composite formulations based on dolomite mixtures, developed by the authors, as practical, circular-economy-based solutions.

To promote integrated strategies that can contribute to long-term soil health, ecological balance, and sustainable land use.

By combining literature insights with case-based innovations, this paper reinforces both the scientific foundation and real-world applicability of advanced soil restoration solutions.

2. Environmental Effects of Soil Degradation/Contamination

Figure 2 shows the schematic illustration of the interconnected environmental impacts of soil degradation, highlighting the cascading effects on soil fertility, water quality, biodiversity, and food security.

2.1. Loss of Soil Fertility

Contaminants such as heavy metals, pesticides, and industrial chemicals can degrade soil, leading to reduced agricultural productivity and poor crop yields. Petroleum industry operations, encompassing drilling, exploration, storage, transportation, processing, and refining, are significant contributors to petroleum hydrocarbon spillage. This results in terrestrial oil pollution characterized predominantly by the presence of hydrophobic compounds [30]. The release of petroleum hydrocarbons into the environment presents a significant threat to ecosystems and poses substantial risks to human health and the environment [31]. Petroleum hydrocarbons are naturally abundant, complex heterogeneous mixtures primarily composed of hydrocarbons, with notable quantities of nitrogen, oxygen, sulfur, and trace metals. They exist in various states, including solid, liquid, and gaseous forms. Petroleum hydrocarbons can be categorized into four main structural groups based on their geographical origin: saturates, aromatics, asphaltenes, and resins [32]. Crude oil composition varies by source but generally consists of 82–85% carbon, 10–14% hydrogen, 0.01–7% sulfur, 0.02–2% nitrogen, and 0.1–1% oxygen [33]. Petroleum hydrocarbon release is a global environmental issue. Recently, soil pollution by petroleum hydrocarbons has surged, contaminating many arable lands with organic compounds. This contamination diminishes the availability of arable land and negatively impacts agricultural practices, such as decreased yields, and contributes to health hazards [34]. Petroleum and its products primarily cause adverse changes in all soil properties, impacting everything from soil layer morphology to humic acid chemistry. Petroleum is recognized as one of the most hazardous environmental contaminants owing to its significant toxicity and widespread presence in the biosphere. When evaluating its detrimental effects, petroleum, along with its derivatives and by-products, is considered second only to radioactive contaminants [33]. The accumulation of spilled petroleum hydrocarbons in the soil at high levels is hazardous to human health and the environment. Soils are major dumps for organic contaminants of various origins and characteristics. Petroleum hydrocarbons contain toxic components that pollute groundwater and soil, alter the soil microbial community, and adversely affect human health and other living organisms [35]. Petroleum spills resulting from mining and processing accidents inflict considerable damage on ecosystems. In these instances, soil is predominantly impacted due to its capacity to accumulate substantial amounts of pollutants, facilitated by its extensive adsorptive surface area. Petroleum contamination adversely affects soil biocenosis, significantly alters the chemical composition, structure, and properties of soil, and diminishes its fertility and agricultural value. Such spills can transform soils into typical technogenic deserts, where biological processes are virtually non-existent. Petroleum-contaminated soils are unsuitable for agricultural and recreational purposes and pose potential risks for contaminating surface and groundwater sources [33]. Petroleum hydrocarbon contaminants (PHCs) are distinguished by their substantial resistance to physical, chemical, and biological degradation processes, resulting in their prolonged persistence in environmental settings. Additionally, PHCs have the capacity to accumulate within living organisms (bioaccumulation) and to amplify in concentration along trophic levels (biomagnification). They also demonstrate significant mobility across various environmental media and exhibit considerable adsorption onto soil organic matter. The inherent toxicological properties of PHCs pose significant risks to both environmental and human health [36]. Polycyclic aromatic hydrocarbons (PAHs) are highly hazardous pollutants due to their remarkable stability, toxicity, and carcinogenic potential. Hydrocarbon contaminants lead to both immediate and delayed effects, including genetic mutations, immunotoxicity, teratogenicity, neurotoxicity, significant immune toxicity, chromosomal damage, carcinogenesis, high bioaccumulation potential, and the degradation of ecosystem functionality. These contaminants adversely impact both animal and plant life [37]. The self-restoration of petroleum-contaminated soils can be a prolonged process, often spanning 10 to 30 years or even longer, depending on the soil type and specific environmental conditions [38].

Heavy metal contamination, including arsenic (As), represents a major threat to soil quality and agricultural productivity worldwide [39]. Arsenic exists in two primary oxidation states: As (III), commonly found in anaerobic (reducing) soils, and As (V), prevalent in oxidizing (aerated) environments [40,41]. Both species are toxic to plants and soil microorganisms, impairing nutrient uptake, inhibiting root development, and ultimately reducing soil fertility. The presence of arsenic in agricultural soils often originates from historical pesticide use and industrial pollution, and its remediation is both difficult and time-consuming. In addition to its persistence in soil, arsenic can migrate into crops and groundwater, compounding environmental and health risks. Anthropogenic sources, such as emissions from coal-fired power plants, contribute significantly to atmospheric arsenic deposition, particularly near industrial areas, with concentrations reaching up to 50 ng/m³ [42]. These processes collectively reduce the biological productivity of soils, disturb microbial ecosystems, and lead to long-term fertility decline.

2.2. Water Pollution

Nearby water bodies and wetlands suffer due to pollution, while cropland productivity decreases significantly as a result of soil erosion. According to FAO estimates, soil erosion can reduce crop yields by up to 50% in severely affected areas, particularly where topsoil loss exceeds 10 tonnes per hectare per year [43]. A leading cause of soil erosion is rainwater, which breaks soil apart, removes it from its location, and carries it away as runoff. Additionally, the type of land use influences the process of soil erosion [44,45]. Besides traditional pathways of soil pollution like using pesticides in agriculture and industrial or urban pollution through contaminated groundwater or irrigation with polluted water, the dangers of airborne soil contamination often receive less attention [46]. Recently, with the exponential increase in plastic waste, nano- and microplastics have gained significant attention due to their prevalence and suspected negative ecological impacts on inshore waters, the sea, and soil. In these environments, plastic waste undergoes mechanical and photochemical degradation, breaking down into smaller, biologically active particles. Manufactured plastics often contain up to 50% of their weight in chemical additives like phthalates, bisphenols, flame retardants, per- and polyfluoroalkyl substances, PCBs, and heavy metals. These additives are used to impart specific properties, such as color, flexibility, fire resistance, and water resistance. However, many of these additives are known carcinogens, endocrine disruptors, and neurotoxicants. They are not chemically bound to the plastic matrix, allowing them to leach out from microplastic particles and enter the environment or human tissues [47]. Nano- and microplastic particles in polluted seawater primarily enter the human body through the consumption of contaminated seafood. However, some of these particles may also transition from polluted seawater, soil, or household sources into the air as particulates or dust, leading to potential inhalation exposure over long distances. Additionally, the contamination of drinking or irrigation water with nano- and microplastics, along with industrially engineered nanomaterials from wastewater, raises concerns about exposure through the ingestion of contaminated water [46]. In agricultural systems, fertilizers are widely used to boost plant growth, but excess nitrogen, typically as nitrate, can leach from the soil into streams and rivers, eventually reaching drinking water [48]. The significant impact of agricultural and industrial activities on water quality, with contaminants like pesticides, heavy metals, and nitrates leaching into water bodies. Intensive farming practices exacerbate soil erosion and nutrient runoff, further degrading surface water quality. Urban expansion contributes to this issue by altering water infiltration patterns and increasing pollutant transport. Both industrial and mining activities deposit heavy metals in soils, which can then contaminate water through runoff. To counter these negative impacts, integrated land and water management practices are crucial, focusing on reducing soil erosion and managing water contamination to safeguard soil health and water quality.

2.3. Decreased Biodiversity

Ineffective land management results in a significant loss of soil biodiversity, threatening global food production systems. Ecosystems are collapsing due to deforestation, grassland loss, wetland drainage, and flow disruptions, leading to a biodiversity crisis and the highest extinction rate in Earth’s history. Five key trends are apparent, including soil degradation and associated biodiversity loss, undermining food production and essential ecosystem services; deforestation and forest degradation, notably in tropical regions; conversion of natural grasslands to erosion-prone, species-poor ecosystems; disappearance of wetlands, endangering freshwater biodiversity; a mass extinction, marking the unprecedented loss of wild plant and animal species [49]. The decline in soil biodiversity, resulting from various individual or combined factors, directly affects surface ecosystems. This loss is more than a conservation concern; it hampers numerous ecosystem functions like decomposition rates, nutrient retention, soil structure development, and nutrient cycling [50]. The degradation of soil and loss of biodiversity are interconnected processes, forming a detrimental cycle. When land is degraded—through activities like over-farming, deforestation, or pollution—the environment for soil microorganisms becomes hostile. These organisms are vital for nutrient cycling and maintaining soil health. As their habitat diminishes, their populations decline, impairing the soil’s ability to recover and function effectively. Soil organisms, including earthworms, fungi, and various microorganisms, play crucial roles in maintaining soil structure. Their movements create channels that improve aeration and water drainage. When these organisms are reduced due to biodiversity loss, the soil becomes compacted, leading to poor drainage and increased erosion risk. As biodiversity diminishes, the functions that organisms provide—like breaking down organic matter, recycling nutrients, and promoting plant growth—are also lost. This leads to weakened soil structure, reducing its resistance to erosion from wind and water. The result is accelerated soil degradation, which further reduces biodiversity, continuing the cycle [51,52,53].

Overall, maintaining soil biodiversity is essential to preserve soil health and prevent degradation. This relationship highlights the importance of integrated land management practices to protect ecosystems and sustain their functions.

2.4. Erosion

Soil erosion intensifies soil degradation, creating a reciprocal relationship, as diminished soil quality can trigger a deterioration trend. Indeed, soil erosion can be seen as an indication of soil degradation as it entails the physical displacement of soil both vertically and horizontally, thereby degrading its quality. The acceleration of this process due to anthropogenic disturbances can severely affect both soil and environmental quality. The mechanism of soil erosion encompasses a three-stage process: detachment, transportation, and deposition of soil particles [54]. The susceptibility to erosion varies with soil type: for example, sandy soils are highly prone to wind erosion due to their low cohesion and particle size, while silty soils are particularly vulnerable to water erosion, especially on sloped terrains. Clay-rich soils, although generally more cohesive, can become highly erodible once their structure is degraded or compacted as they tend to form surface crusts and generate high runoff [55,56,57]. Soils with poor aggregate stability or lacking in organic matter are less able to resist detachment and are more easily transported by wind or water [56,58]. Soil erosion significantly impacts agriculture, influencing both crop yield and long-term sustainability. Erosion removes the nutrient-rich topsoil, essential for plant growth. This loss reduces soil fertility and crop yield, prompting farmers to rely more on fertilizers, which can increase costs and environmental impact [59,60]. The eroded soil typically lacks organic matter, leading to decreased water retention capacity. This condition makes crops more susceptible to drought and necessitates increased irrigation, raising agricultural costs [61]. Soil erosion leads to a denser and more compacted soil structure, which restricts root development and reduces the infiltration of air and water, ultimately impairing crop growth and productivity [62]. Prolonged erosion can significantly reduce the availability of arable land, limiting the area suitable for cultivation. Moreover, erosion-related nutrient runoff is a key contributor to freshwater and coastal eutrophication [63], and soil biodiversity loss from erosion has been found to impair microbial-driven functions critical to crop resilience [64,65]. The loss of the topsoil layer also leaves plants more vulnerable to diseases and extreme weather, increasing dependence on chemical plant protection measures [63]. As a consequence, reduced crop yields can translate into economic losses for farmers and potentially lead to rising food prices [64].

Table 1. Erosion susceptibility of different soil types and appropriate control strategies.

Soil Type	Main Erosion Mechanism	Vulnerability	Recommended Control Measures
Sandy soils	Wind erosion	Low cohesion; easily blown away; poor nutrient and water retention [55,56]	Windbreaks, cover crops, mulching
Silty soils	Water erosion	High erodibility on slopes; forms crusts; easily detached by raindrop impact [56,58]	Contour farming, vegetative buffer strips, reduced tillage
Clay soils	Water erosion	Compacts easily; high runoff once structure is degraded; crust formation [57,65]	Organic matter addition, minimum tillage, cover crops
Loamy soils	Moderate (wind and water)	Balanced texture but vulnerable when organic matter is low [55,56]	Crop rotation, conservation tillage, residue management
Peaty soils	Water and wind erosion	Low structural strength; rapid loss when drained [58,66]	Permanent vegetation, water table management
Volcanic soils	Water erosion	Highly porous and fragile; prone to landslides on slopes [56,65]	Terracing, reforestation, controlled grazing

summarizes how different soil types respond to erosion mechanisms, along with their vulnerabilities and recommended control measures. To counter these effects, it is essential to implement erosion control strategies such as contour farming, cover cropping, and maintaining permanent vegetation cover. These practices have proven to be highly effective in reducing soil erosion and preserving long-term soil productivity. For instance, contour farming can reduce soil loss by 25–50% on moderate slopes by slowing runoff and increasing water infiltration [65]. Cover crops contribute not only to erosion reduction (by up to 90% in some no-till systems [66]) but also enhance organic matter content and microbial activity. Permanent vegetation, such as buffer strips or grassed waterways, can trap 70–85% of sediment before it leaves the field, protecting water bodies and nearby ecosystems [56,57]. While contour farming is more suitable for row-crop systems in hilly areas, cover crops are widely applicable and particularly valuable during off-seasons, and permanent vegetation is most effective in riparian zones or areas prone to runoff accumulation. The integration of these strategies, adapted to local soil types and topography, ensures greater resilience against erosion while supporting sustainable agriculture and biodiversity conservation.

2.5. Increased Greenhouse Gas Emissions

Societal challenges, including food security, sustainability, climate change, carbon sequestration, greenhouse gas emissions, and the degradation of soil through erosion and the depletion of organic matter and nutrients, are intricately interconnected with the soil resource. Soil systems are intricately linked to climate regulation, particularly through their role in greenhouse gas (GHG) emissions and carbon sequestration. Intensive agriculture and poor land management have significantly reduced soil organic carbon, contributing to climate change and environmental degradation [67,68]. The extensive use of synthetic and organic fertilizers has increased nitrogen inputs, leading to elevated nitrous oxide (N₂O) emissions—one of the most potent greenhouse gases, with a global warming potential approximately 273 times greater than carbon dioxide (CO₂) over a 100-year period [69]. According to the IPCC 2019 [63] Refinement, approximately 1.0–1.25% of applied nitrogen is released as N₂O through microbial denitrification and nitrification in soils [69,70]. Similarly, methane (CH₄) emissions from flooded or compacted soils arise via methanogenesis under anaerobic conditions, while well-aerated soils mitigate CH₄ through methanotrophy [71]. Soils thus act as both sources and sinks of CH₄, depending on moisture, oxygen, and organic matter availability [72]. These emissions not only contribute to global warming but also accelerate soil degradation by disrupting microbial activity, nutrient cycling, and organic matter retention [73]. Effective mitigation strategies—such as optimized fertilizer use, reduced tillage, cover cropping, and organic matter restoration—can reduce GHG emissions while enhancing soil health and resilience [74,75]. In many regions, the intensification of agricultural practices and land use has led to a decline in the organic matter content in agricultural soils. Furthermore, the extensive application of mineral fertilizers has contributed to atmospheric pollution; greenhouse gas emissions, such as carbon dioxide (CO₂) and nitrous oxide (N₂O); water eutrophication; and potential human health risks. Nutrient management is especially intensive in greenhouse production systems, where nutrient inputs significantly influence the earth’s climate. Globally, around one percent of nitrogen additions is emitted into the atmosphere as nitrous oxide (N₂O), a greenhouse gas with 300 times the warming potential of carbon dioxide [76,77,78]. Soils emit nitrous oxide (N₂O), a greenhouse gas about 300 times more potent for climate warming over 100 years than CO₂. The primary sources of N₂O emissions include agriculture, industry, and biomass burning, indirect emissions from reactive nitrogen through processes like leaching, runoff, and atmospheric deposition. Any soil with available mineral nitrogen (N) can emit N₂O through the mineralization of soil organic matter. However, most emissions are driven by nitrogen additions to the soil, primarily from fertilizers, which can be synthetic or organic, such as manures, slurries, and composts. Due to the strong link between nitrogen addition and N₂O emission, these emissions are often calculated as a direct function of the amount of nitrogen added to the soil [79]. Methane (CH₄) is a potent greenhouse gas, 20–35 times more powerful for climate warming over 100 years than CO₂. Soils emit methane through methanogenesis, a process occurring during the decomposition of organic matter in anaerobic soil layers. Conversely, in aerobic layers, methane is oxidized by methanotrophy. Thus, methane emissions result from the balance between methanogenesis and methanotrophy. Soil management strategies focusing on reducing methane (CH₄) emissions or enhancing CH₄ uptake can bolster the soil’s role in climate regulation. However, enhancing CH₄ uptake in managed soils is challenging, making most mitigation efforts concentrate on reducing CH₄ emissions instead [80]. Increased greenhouse gas emissions significantly contribute to soil degradation, adversely impacting soil health and productivity. Methane and nitrous oxide emissions from agricultural practices and organic matter decomposition accelerate this degradation by altering soil chemistry, reducing organic matter content, and affecting nutrient cycles. These changes impair the soil’s ability to support plant growth, maintain microbial diversity, and regulate water and nutrient retention. Effective soil management strategies that focus on minimizing these emissions and restoring organic matter are crucial for mitigating degradation and enhancing the soil’s overall resilience to climate change.

2.6. Impact on Food Safety

Soil degradation directly impacts food safety by compromising both the quality and quantity of agricultural produce. As soil health declines, its ability to supply essential nutrients to crops diminishes, leading to nutrient-poor food that may not meet dietary needs. Empirical studies have shown that degraded soils with low organic matter and poor microbial activity produce crops with significantly lower micronutrient concentrations, particularly in zinc, iron, and vitamin A precursors [81]. For example, research by Stein et al. (2007) [79] indicates that zinc-deficient soils are a major contributor to zinc deficiency in human diets across South Asia [82]. Similarly, soil acidity and aluminum toxicity reduce phosphorus and calcium uptake, impairing grain quality in staple crops such as maize and rice [83].

Degraded soils are also more prone to erosion and waterlogging, which can introduce contaminants and pathogens into the food supply, increasing the risk of foodborne illnesses. Additionally, degraded soils often require increased use of chemical fertilizers and pesticides to maintain crop yields, potentially leaving harmful residues in food [84]. Maintaining healthy soils is, therefore, crucial for ensuring safe and nutritious food production.

In agricultural regions, the challenge has been to increase food production within economic and institutional frameworks that often lack the means to enhance productivity sustainably. The pressure to boost output without supportive measures has resulted in a substantial expansion of agricultural land—over 65 percent in the past thirty years—and a reduction in fallow periods in traditional, extensive land use systems. This reduction has limited the natural restoration of soil fertility. Additionally, the intensified use of fire for land clearing has further depleted nutrients in numerous systems. Reduced fallow periods and increasing fire incidence accelerate soil degradation by depleting soil organic carbon, disrupting microbial communities, and exacerbating erosion processes [85,86]. In tropical shifting cultivation systems, shortened fallow cycles are linked to declining soil fertility and reduced crop yields [87]. Likewise, repeated burning leads to the volatilization of key nutrients and long-term damage to soil structure [88].

Fertilizer consumption has not increased proportionally to compensate for nutrient losses from intensified land use, leading to widespread depletion of soil organic matter and nutrients. Consequently, degraded croplands are often characterized by low organic matter, acidic pH, and aluminum toxicity. On such soils, inorganic fertilizers are more prone to leaching, further lowering nutrient-use efficiency and impacting water quality downstream [89].

Soil contamination poses a multifaceted threat to food security by directly impacting both crop yields and the safety of food products. Contaminants such as heavy metals and persistent organic pollutants can impair plant growth, reduce productivity, and accumulate in edible tissues. Crops grown on contaminated soils may thus pose health risks to consumers, affecting the availability of safe, nutritious food and threatening public health.

Diffuse soil contamination—resulting from widespread inputs of pollutants such as nitrates, heavy metals, and pesticides—can accumulate over time and contribute to chronic exposure pathways through food and water, with documented health risks such as cancer, endocrine disruption, and neurotoxicity [90,91,92]. Although these diffuse contaminants may not immediately impact yields, they can accumulate to toxic levels in food crops, especially leafy vegetables and grains [93].

The challenge lies in managing contamination sources and implementing effective agricultural practices that mitigate risks to crop productivity and food safety. Addressing soil contamination through remediation, improving industrial waste management, and adopting precision agriculture and organic farming are critical steps toward ensuring the sustainability and safety of global food systems.

3. Recent Advances in Mitigating Soil Degradation/Decontamination

Recent advances in mitigating soil degradation and decontamination have focused on sustainable practices and innovative technologies. The schematic diagram (Figure 3) summarizes the main strategies currently employed to address soil degradation and contamination. The approaches are grouped into key categories: phytoremediation, bioremediation, mycoremediation, nanotechnology, bio-based inputs, precision agriculture, and organic amendments. Each method plays a specific role in restoring soil health—whether by enhancing biological activity, stabilizing contaminants, or improving soil structure and fertility. The diagram highlights the interconnectedness of these techniques and their contribution to sustainable soil management and environmental protection.

Phytoremediation: This plant-based approach uses specific plants to absorb, sequester, and detoxify contaminants from the soil. Researchers are optimizing plant species that are more effective at extracting heavy metals and other pollutants. Biochemical mechanisms facilitate the maintenance of lower metal concentrations within the cytoplasm compared to the surrounding soil, thereby mitigating the detrimental effects of heavy metals on cytoplasmic organelles. This regulation is accomplished via vacuolar sequestration. Plant species lacking an elimination mechanism can uptake and translocate substantial quantities of heavy metals, storing them in their shoots without displaying any toxic symptoms [94]. The sequestration or compartmentalization of metals within cellular compartments, particularly vacuoles, facilitates heavy metal tolerance. This process protects vulnerable cellular regions from heavy metals and prevents the inhibition of cytoplasmic metabolic processes. In contaminated environments, organic solutes and amino acids such as proline support plant growth. The complexation of metals with solutes diminishes the transport of heavy metals to sensitive plant tissues [95]. The concept of avoidance tactics in plants refers to their ability to control the absorption of heavy metals (HMs) and limit their movement into plant tissues through root cells [96]. However, when avoidance or sequestration fails, toxic elements can accumulate in edible plant parts, posing significant risks to human health. For instance, leafy vegetables like spinach (Spinacia oleracea) and lettuce (Lactuca sativa) grown in cadmium-contaminated soils have been shown to accumulate Cd levels up to 1.2 mg/kg and 0.95 mg/kg, respectively—well above the EU maximum permissible limit of 0.2 mg/kg in edible vegetables [97]. Similarly, rice grains cultivated in arsenic-contaminated paddy fields have recorded As concentrations exceeding 0.3 mg/kg, raising concerns in Southeast Asia where rice is a staple food [98]. In another study, Indian mustard (Brassica juncea) grown on lead-contaminated soils accumulated Pb concentrations of over 5 mg/kg in edible leaves, exceeding safety limits and highlighting its dual use as a phytoextractor and food risk [99]. These findings underscore the importance of carefully selecting plant species for phytoremediation in agricultural contexts, particularly when food crops are involved. Five types of phytoremediation mechanisms are used to clean up affected soils. These methods include [100] the following: (i) Phytoextraction involves the uptake and accumulation of contaminants (typically heavy metals) in plant tissues. It is effective for low-to-moderate contamination levels but is limited by slow biomass growth and metal bioavailability—plants (Sesuvium portulacastrum [101], Noccaea caerulescensis [102], Melilotus officinalis and Amaranthus retroflexus [103], Pennisetum purpureum [104], and Alternanthera bettzickiana’s [105]) absorb pollutants through their roots and store them in their tissues. (ii) Phytodegradation or Phytotransformation uses plant enzymes to break down organic contaminants (e.g., hydrocarbons and pesticides), offering sustainable in situ remediation, though it is ineffective for inorganic pollutants—plants (Vetiveria zizanioides [106], Nicotiana tabacum [107], Populus deltoids [108], and Typha latifolia [109]) break down pollutants into less harmful substances. (iii) Phytovolatilization transforms pollutants into volatile forms released into the atmosphere. While it can be efficient for elements like mercury or selenium, it raises concerns over air quality and secondary pollution—plants (Brassica juncea [110]) release pollutants into the air through their leaves. (iv) Phytofiltration employs plant roots (often in hydroponic systems) to absorb or precipitate contaminants from water. It is efficient for wastewater treatment but requires frequent biomass management—parts of plants (Atriplex halimus [111] and Indian mustard (B. juncea) and sunflower (H. annuus) [112,113,114]), such as roots, shoots, or seedlings, are used to remove contaminants from polluted surface waters or wastewater. (v) Phytostabilization reduces contaminant mobility by immobilizing them in the rhizosphere. It is suitable for preventing leaching and erosion but does not remove pollutants from the site—plants (Sorghum bicolor and Carthamus tinctorius [115], Erica australis [116], and Helichrysum microphyllum [117]) immobilize pollutants in the soil to prevent their spread.

Bioremediation has emerged as a promising eco-friendly strategy for detoxifying contaminated soils. This technique utilizes microorganisms—primarily bacteria and fungi—to break down or neutralize organic pollutants such as petroleum hydrocarbons (PHCs). These microorganisms facilitate the biotransformation of complex contaminants into simpler, less harmful substances including carbon dioxide, water, and inorganic compounds [118]. Studies have shown that a wide range of microbial species, along with certain algae and plants, are capable of fully mineralizing PHCs in both soil and aquatic environments [102]. Bioremediation encompasses not only microbial activity but also the role of plant-derived enzymes and metabolites in the detoxification process [119].

Mycoremediation, a subset of bioremediation, employs fungal networks to degrade persistent organic compounds and immobilize heavy metals. Through their extensive hyphal systems and metabolic capacity, fungi can mineralize pollutants into harmless end-products such as carbon dioxide, water, and microbial biomass, reducing the risk of contaminant bioaccumulation in the food chain [120]. Mycoremediation represents a sustainable biotechnological approach that employs fungi, as well as associated microorganisms such as bacteria and microalgae, for the degradation and removal of a wide range of environmental contaminants. Specific fungal species have demonstrated targeted bioremediation capabilities against distinct classes of pollutants. For instance, Penicillium simplicissimum is effective in degrading synthetic dyes such as Crystal Violet, Methyl Violet, Malachite Green, and Cotton Blue. Lasiodiplodia sp. has been identified as a potent degrader of Malachite Green, while Cylindrocephalum maurelium shows activity against Mordant Orange-1. In the case of Methyl Blue dye, Aspergillus carbonarius has proven effective. Heavy metal pollutants are also targeted by various fungal species: an Ascomycota consortium is capable of bioaccumulating metals such as Mn, Fe, Cu, Cr, and As; Penicillium chrysogenum demonstrates efficiency in removing Cd(II), Pb, and Cu(II); and Talaromyces islandicus specifically targets Pb. For organic pollutants, Bjerkandera adusta is active against the herbicide Atrazine, while Phlebia lindtneri and Phlebia brevispora are efficient in degrading Lindane, an organochlorine insecticide. Trichoderma harzianum has been shown to degrade polyethylene, a persistent plastic pollutant. Furthermore, Aspergillus niger is capable of degrading the organophosphorus pesticide Diazinon, Fusarium proliferatum targets the insecticide Allethrin, and Trametes versicolor has been utilized for the degradation of the pharmaceutical compound Ketoprofen [121,122].

In parallel, bio-based agricultural inputs such as biopesticides and biofertilizers have gained attention as sustainable alternatives to synthetic chemicals. These products enrich soil microbiomes, enhance nutrient availability, and reduce chemical load, thus preventing further soil degradation.

Precision agriculture technologies, including GPS mapping, soil sensors, and drones, further contribute to sustainable land management. By optimizing input application—particularly fertilizers and irrigation—these innovations minimize environmental contamination and conserve soil resources.

Finally, the application of organic soil amendments, such as biochar, has been shown to improve soil structure, increase nutrient retention, and immobilize contaminants, making them less bioavailable to plants and reducing their ecological impact.

Nanotechnology: Nano-remediation is an innovative approach that addresses the significant pollution challenges of the 21st century. By utilizing nanostructures for environmental remediation, it becomes feasible to reduce the overall costs associated with decreasing large-scale pollution. This method is time-efficient and negates the necessity for additional disposal stages of recycled materials [123]. Compared to traditional materials, nanomaterials offer a higher surface area, leading to enhanced reactivity and increased productivity. Their unique surface chemistry can be tailored with functional groups for selective and efficient contaminant remediation [124]. Since soil and groundwater pollution are closely linked, nanomaterials used for remediation in both mediums—such as nano zero-valent iron (nZVI), bimetallic nanoparticles (e.g., Fe/Pd and Fe/Ni), and emulsified nZVI particles—have gained widespread application [125,126,127]. For example, nZVI has been used to reduce hexavalent chromium (Cr⁶⁺) to the less toxic Cr³⁺ in industrially contaminated soils, with reduction efficiencies exceeding 90% within a few hours [128]. In another case, Fe/Pd bimetallic nanoparticles effectively degraded trichloroethylene (TCE), a common chlorinated solvent, in both lab-scale and pilot-scale remediation trials [129]. Similarly, TiO₂ nanoparticles have been applied to soils contaminated with organic dyes and pesticides, utilizing photocatalytic degradation under sunlight exposure [130]. Utilizing nanoparticles to immobilize or remove contaminants is a burgeoning field. These particles can be engineered to capture and detoxify specific pollutants in the soil. However, growing concern surrounds the unintended release and accumulation of nano- and microplastics in terrestrial and aquatic environments, which has been associated with adverse effects on human health. Studies indicate that microplastics can enter the food chain through agricultural soils and eventually reach humans via crops or drinking water, potentially causing oxidative stress, inflammation, and endocrine disruption [131]. Nanoplastics, due to their small size, may even cross biological barriers such as the blood–brain barrier and placental barrier, raising concerns over their neurotoxicity and developmental effects [132,133].

Increasing awareness and providing training for sustainable land management practices help prevent further degradation. Policy frameworks support the restoration of contaminated lands and encourage sustainable agricultural practices.

Together, these advances not only help in rehabilitating contaminated soils but also enhance the resilience and productivity of agricultural landscapes, ensuring long-term food security and environmental health. However, the deployment of remediation technologies must be accompanied by a comprehensive environmental risk assessment to ensure their safety and sustainability. For instance, while nanomaterials offer high efficiency in contaminant removal, their long-term behavior, ecotoxicity, and potential for bioaccumulation in soil organisms and food chains remain insufficiently understood and require careful monitoring [134]. Similarly, phytoremediation strategies, though environmentally friendly, may lead to the unintentional entry of toxic elements into edible plant parts, posing food safety risks if not properly managed [135].

In addition, soil amendments—such as industrial by-products or organic residues—must be evaluated for potential secondary contamination, alterations in microbial diversity, and changes in soil physicochemical properties. Therefore, the implementation of these technologies should involve site-specific assessments, long-term monitoring programs, and alignment with environmental protection regulations. Only through an integrated, precautionary approach can these innovations deliver effective and safe outcomes for soil restoration and ecosystem health.

4. Comparative Evaluation of Dolomite-Based Soil Conditioners and Conventional Amendments

4.1. Comparative Analysis of Amendments

In the context of circular economy and sustainable soil remediation strategies, recent innovations have focused on valorizing industrial by-products through engineered mixtures. This section synthesizes findings from patented technologies and previously validated approaches involving dolomite-based composites for treating degraded and contaminated soils. These case studies exemplify the practical implementation of concepts discussed in the literature and demonstrate the potential of such mixtures in soil restoration frameworks.

Table 2. Comparative analysis of dolomite-based and conventional soil amendments across key criteria such as remediation efficacy, soil-type suitability, cost, potential side effects, and primary contaminants targeted.

Soil Amendment	Primary Contaminants Targeted	Mechanism of Action	Soil Type Suitability	Remediation Efficacy	Known Side Effects	Cost per Ton (EUR)	Sources
Dolomite + Sewage Sludge	PAHs, Nutrient Deficiency	Nutrient supply, microbial stimulation, sorption	Degraded agricultural soils	High (PAH by 60–80%)	Heavy metal load from sludge; needs monitoring	25–35	[136]
Dolomite + Steel Slag	Petroleum Hydrocarbons	Alkalinity, catalytic degradation, physical sorption	Industrial and hydrocarbon-contaminated soils	High (TPH >50%)	High pH can disrupt native microbiota	20–30	[137]
Dolomite + Zeolite	Heavy Metals (Cd, Pb, Zn)	Ion exchange, pH buffering, adsorption	Heavy metal-contaminated soils (acidic)	High (bioavailable metals 40–70%)	May remobilize metals after liming effect diminishes	30–40	[138]
Biochar	Heavy Metals, Organic Pollutants	Sorption, redox interaction, microbial support	Versatile; degraded and contaminated soils	High (depends on feedstock and activation)	Potential release of polyaromatic compounds	100–400	[62]
Apatite	Heavy Metals (Pb, Zn, Cd)	Phosphate precipitation, metal immobilization	Acidic soils with high metal load	Moderate to high (depends on solubility)	P accumulation in runoff; eutrophication risk	150–300	[139]
Bentonite	Heavy Metals (As, Cd)	Cation exchange, water retention, swelling	Clayey, acidic soils	Moderate (slow response)	Swelling can affect soil porosity	60–100	[140]
Fly Ash	Heavy Metals, pH Correction	pH modification, metal immobilization, liming effect	Acidic and contaminated soils	Moderate (site-dependent)	Toxicity risk if not treated	20–50	[141]
Humic Substances	Heavy Metals, Organic Pollutants	Chelation, complexation, metal mobility reduction	Nutrient-poor or contaminated soils	Moderate (long-term stability uncertain)	Variable quality; may introduce organics	80–150	[142]
Compost	Nutrients, Pathogens	Organic enrichment, microbial stimulation	Depleted or pathogen-affected soils	Moderate (effective in nutrient cycling)	Odor, pathogen risk if not composted well	30–70	[59]
Green Manure	Organic Matter Depletion	Nitrogen fixation, organic matter input	Low organic matter soils	Moderate (beneficial for fertility restoration)	Requires biomass management	15–40	[143]
Lime	Soil Acidity	pH correction, reduces Al toxicity	Strongly acidic soils	High (rapid pH correction)	Over-liming may cause micronutrient deficiencies	50–100	[144]

addresses reviewer comments regarding the need for a more comprehensive scientific synthesis of existing technologies in contrast to patented formulations.

4.2. Case Study: Dolomite–Sewage Sludge

One notable strategy involves the synergistic use of dolomite and sewage sludge, a concept supported by prior studies [136,145] that highlight the benefits of combining organic and inorganic amendments. These mixtures create a composite with enhanced structural stability, improved nutrient availability, and reduced toxic element concentrations.

Dolomite, a calcium–magnesium carbonate, is known to regulate pH and provide essential nutrients such as Ca and Mg, both crucial for plant development. The morphology and EDX mapping of dolomite can be seen in Supplementary File (Figures S1 and S2) Sewage sludge contributes organic matter and a variety of micronutrients, boosting fertility and supporting microbial activity. When applied in tandem, these amendments can enhance soil texture, water retention, and biodegradation of contaminants through microbial pathways.

Documented advantages of such mixtures include the following:

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Soil fertility restoration via mineral and organic nutrient input.

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pH correction and nutrient balance, particularly in acidic and depleted soils.

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Improved soil structure due to organic matter promoting aggregation.

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Resource recycling, aligning with EU circular economy goals.

Contaminant mitigation, notably polycyclic aromatic hydrocarbons (PAHs), through sorption and microbial degradation mechanisms.

One nationally patented formulation describes the use of a dolomite-to-sewage sludge ratio of 1:2, with both components characterized for their beneficial properties [136]. The analytical results available in the patent documentation indicate notable reductions in PAH concentrations post-application, suggesting the mixture’s potential for restoring soil health and enhancing agricultural productivity. These outcomes fall within the safety thresholds stipulated by Romanian Order No. 344/708/2004, which aligns with EU regulatory frameworks [146,147,148]. Although laboratory-scale tests and patent data confirm the reduction in PAHs and improvements in soil fertility, further long-term field trials are necessary to assess this formulation’s performance under different climate, crop, and irrigation conditions. Validation through multi-season agronomic trials would confirm its practical reliability and environmental safety.

Such patented solutions underscore the applicability of mineral–organic mixtures for the remediation of degraded soils and demonstrate how by-products can be transformed into value-added products for sustainable agriculture.

4.3. Case Study: Dolomite–Slag

Stainless steel slag serves as an effective absorbent for petroleum hydrocarbons due to its porous structure and alkaline composition, while dolomite enhances the stabilization of the mixture and contributes to pH regulation [149,150,151,152]. Moreover, metallurgical slags have been previously shown to immobilize or catalytically degrade hydrocarbons while simultaneously improving soil fertility through the release of essential minerals and the enhancement of soil structure [153,154]. Another patented approach involves using a dolomite and stainless-steel-slag mixture to target soils contaminated with petroleum hydrocarbons [137]. The innovation leverages the alkaline and porous nature of steel slag to absorb and partially degrade hydrocarbons, while dolomite contributes to pH buffering and soil stabilization.

Studies and patents concerning this mixture have demonstrated the efficacy of combining dolomite (rich in CaCO₃ and MgCO₃) with slag (containing reactive oxides such as CaO, Fe₂O₃, and MgO) in a 1:1 mass ratio. This blend has been shown to enhance hydrocarbon adsorption through surface interactions and catalytic degradation pathways, outperforming conventional absorbents like clay or activated carbon in some applications.

The patent literature reports that application of this mixture to contaminated soils resulted in a substantial decrease in total PAH concentrations, bringing them below the recommended safety limit of 5 mg/kg (as per Order No. 344/708/2004). This approach is aligned with the goals of the EU Mission “A Soil Deal for Europe”, which emphasizes innovative soil recovery technologies. The patent literature supports the efficacy of the dolomite–slag blend in PAH remediation, but its long-term behavior under real-world conditions is not yet fully characterized. Field-scale studies should investigate contaminant leaching risk, pH buffering longevity, and soil–plant interactions across multiple crop cycles to ensure its safe integration into agricultural systems.

The formulation provides a cost-effective, scalable solution for remediating hydrocarbon-impacted soils, especially in post-industrial or petroleum-polluted areas. However, as noted in the patent documentation, further field studies and ecotoxicological assessments are required to validate its long-term environmental impact and agronomic efficacy.

4.4. Case Study: Dolomite–Zeolite

Another effective approach involves combining dolomite with natural zeolite, which offers synergistic absorption and immobilization capacity for heavy metals such as Cd, Pb, and Zn [138]. A field experiment carried out in the heavily contaminated region of Copșa Mică (Romania) compared amendments including dolomite, zeolite, bentonite, and manure. The results after two years demonstrated that dolomite and natural zeolite notably increased soil pH, significantly reduced metal bioavailability, and lowered plant uptake of lead and zinc compared to untreated control plots.

The key benefits of this mixture include the following:

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pH regulation and metal immobilization: Dolomite raises soil pH, decreasing metal solubility, while zeolite’s high cation exchange capacity adsorbs heavy metals, reducing their mobility and uptake.

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Sustained environmental safety: Over two years, the treatment kept metal bioavailability low, although caution is advised regarding potential re-mobilization of metals after the liming effect diminishes.

In contrast, the Copșa Mică field study represents a well-documented two-year validation of this approach, demonstrating reduced heavy metal bioavailability and improved soil conditions in a historically contaminated area. These results suggest field-proven potential for metal immobilization, although continued monitoring is recommended to confirm the persistence of immobilization effects beyond the liming period.

The dominant processes involved from the last 5 years to strengthen the scientific foundation include the following:

Ion Exchange and Adsorption: Zeolite’s high cation exchange capacity (CEC) allows it to immobilize heavy metals (e.g., Pb²⁺ and Cd²⁺) by exchanging them with Na⁺, K⁺, and Ca²⁺ on its aluminosilicate framework [155]. This reduces metal mobility and phytoavailability in soil solutions.

pH Increase and Precipitation: Dolomite and steel slag increase soil pH, leading to metal precipitation as carbonates or hydroxides (e.g., Pb(OH)₂ and ZnCO₃) [156,157]. Higher pH also reduces the solubility of toxic metals.

Complexation with Organic Matter: Sewage sludge contains humic and fulvic acids that bind metals via carboxyl and phenolic groups, forming stable organic–metal complexes [158].

Formation of Stable Mineral Phases: Calcium from dolomite and slag can react with phosphate or carbonate ions to form insoluble compounds like hydroxyapatite (Ca₅(PO₄)₃OH), which entraps Pb²⁺ or Cd²⁺ [159].

Sorption to Iron and Manganese Oxides: Steel slag contains Fe and Mn oxides, which act as strong sorbents for oxyanions and metal cations through surface complexation [160].

This section highlighted three validated and documented formulations utilizing dolomite in conjunction with sewage sludge, steel slag, and natural zeolite, each presenting promising strategies for soil remediation. By synthesizing existing knowledge from patents and the peer-reviewed literature, these case studies demonstrate how industrial and natural by-products can be successfully repurposed to restore soil quality, reduce contamination, and support sustainable land management. Several of these formulations, including the dolomite–zeolite mixture tested in the Copsa Mica field study, have shown effectiveness over multi-year monitoring periods, confirming their practical potential. However, despite promising results, long-term field validation remains essential, particularly for patented dolomite–slag and dolomite–sludge compositions. Pilot-scale trials and ecotoxicological monitoring should be implemented to evaluate seasonal stability, contaminant rebound, nutrient cycling, and agronomic performance over extended periods and under diverse environmental conditions. Collectively, these technologies reinforce the connection between scientific innovation, practical application, and the broader goals of the circular economy and environmental protection.

5. Conclusions

This review underscores the pressing environmental and agricultural challenges posed by soil degradation and contamination, including diminished fertility, declining water quality, biodiversity loss, and heightened vulnerability to desertification. As these threats continue to expand—exacerbated by industrial activity, poor land management, and climate change—the need for effective and sustainable mitigation strategies becomes increasingly urgent.

Emerging approaches such as bioremediation, phytoremediation, and nanotechnological interventions offer environmentally conscious alternatives to conventional methods. These technologies hold considerable promise for restoring contaminated soils, particularly those affected by petroleum hydrocarbons or heavy metals. Furthermore, innovative composite formulations—such as dolomite–sewage sludge and dolomite–steel slag mixtures—have demonstrated positive results in improving soil structure, nutrient content, and pollutant reduction. Their application also aligns with circular economy principles by repurposing industrial by-products for environmental benefit.

However, despite their promise, the long-term implications of such amendments require further investigation. Key areas for future research include the following:

The potential re-mobilization of heavy metals under fluctuating pH or redox conditions, which could undermine remediation outcomes;

Alterations in soil microbial communities over time, which may affect soil resilience, nutrient cycling, and ecological balance;

Ecotoxicological assessments to evaluate impacts on non-target organisms and crop safety;

Field-scale trials to validate laboratory findings, optimize application rates, and assess interactions with varying soil types and climates.

Addressing these knowledge gaps is essential to fully validate these amendments and ensure their safe, effective deployment at scale. A holistic approach that integrates material innovation, ecological safety, and long-term monitoring will be critical for advancing sustainable land restoration and climate-resilient soil management.