Biochar-mediated improvements in soil health in drylands: A bibliometric review of the potential and mechanisms for combating desertification and climate change

Waste management and pollution reduction are critical global challenges that demand innovative and sustainable solutions. Traditional methods often fall short in terms of efficiency and environmental impact. Biological nanotechnology, particularly the use of biosurfactants and nanoenzymes, offers promising alternatives for addressing environmental pollutants such as hydrocarbons, textile dyes, and heavy metals. Objective: This study aimed to evaluate the effectiveness of bio-nanotechnology-based solutions, specifically biosurfactants and nanoenzymes, in waste management and pollution reduction, focusing on sustainability and environmental impact. Methods: A quantitative research approach was employed to assess the efficacy of bio-nanotechnology in waste treatment and pollution reduction. Laboratory experiments were conducted to explore the degradation capacity of biosurfactants and nanoenzymes on various pollutants. The study also involved a survey of 167 industry professionals to evaluate the potential of bio-nanotechnology in enhancing waste treatment efficiency and environmental sustainability. Data on pollutant elimination efficacy, degradation rates, soil health, metal contaminant levels, and CO2 emissions were collected. Statistical analysis was performed to compare the outcomes of nano-bioremediation with traditional methods. Results: The laboratory experiments demonstrated a high treatment capacity, with pollutant elimination efficacy exceeding 86% and degradation rates significantly faster than conventional treatments. The survey results indicated that bio-nanotechnology could enhance waste treatment efficiency and environmental friendliness by 20-40%. Nano-bioremediation led to a 23% improvement in soil health, a 32% reduction in metal contaminants, and a 14-19% decrease in CO2 emissions from waste processing compared to conventional methods. Conclusion: The study's findings suggest that bio-nanotechnology presents a novel, sustainable solution for waste management and pollution reduction. The significant improvements in pollutant elimination, soil health, and reduction of metal contaminants and CO2 emissions highlight the potential of this approach to address global environmental challenges more effectively than traditional methods. Further research and development are recommended to optimize and scale up these technologies for broader application.

The aim of the study was to evaluate the changes in glomalin-related soil proteins (GRSP) content, microbial diversity and soil physical quality depending on the type of soil measures of soil improvement and changes in soil health. The study was based on a 100-year stationary field microplot experiment where the soil profiles were collected with preserving the natural soil horizons. The microplot experiment was carried out on eight different soil types: Brunic Arenosol (Dystric I), Rendzic Leptosol, Fluvic Cambisol, Haplic Cambisol (Eutric), Gleyic Phaeozem, Brunic Arenosol (Dystric II), Haplic Cambisol (Eutric II) and Haplic Cambisol (Dystric). These soils are the most common types of agricultural soils in Poland. Relatively significant correlations with the soil quality, physical parameters and the glomalin-related soil proteins have been found. The study determined the total GRSP (T-GRSP) and easily extractable GRSP (EE-GRSP) levels in soils as well as the soil physical quality index and soil’s microbial biodiversity. The GRSP depended on the type of soil and correlated with S-Index and also was responsible for the unique chemical and physical properties of soils. Soils characterized by the highest T-GRSP content belonged to the group of very good and good soil physical quality characterized also by high biological activity, for which there were strong correlations with such parameters as dehydrogenase activity (DHA), microbial biomass content (MBC), microbial nitrogen content (MBN) and total bacteria number (B). The highest T-GRSP content and higher microbial diversity were found in Gleyic Phaeozem, Rendzic Leptosol and Fluvic Cambisol. The T-GRSP and EE-GRSP content were additionally correlated with the number of AMF spores. Very poor and poor soil physical quality according to S-Index characterized Brunic Arenosol (Dystric I) and Haplic Cambisol (Dystric). This research indicates that a specific edaphone of soil microorganisms and GRSP content may be of great importance when assessing a soil’s quality and improvements in soil health. The abundance of glomalin-producing fungi significantly affects the quality of the soil. This effect is particularly important for agricultural soils are threatened by ongoing land degradation.

Soil, a natural four‐dimensional body at the atmosphere–lithosphere interface, is organic‐carbon‐mediated realm in which solid, liquid, and gaseous phases interact at a range of scales and generate numerous ecosystem goods and services. Soil organic carbon (SOC) strongly impacts soil quality, functionality and health. Terms soil quality and soil health should not be used interchangeable. Soil quality is related to what it does (functions), whereas soil health treats soil as a living biological entity that affects plant health. Through plant growth, soil health is also connected with the health of animals, humans, and ecosystems within its domain. Through supply of macro‐ and micronutrients, soil health, mediated bySOCdynamics is a strong determinant of global food and nutritional security. Soil C pool consists of two related but distinct components:SOCand soil inorganic C (SIC). TheSICpool comprises of primary and secondary carbonates, and the latter consists of calcitic (no net sequestration of atmosphericCO2) and silicatic (net sequestration). WhileSOCis highly dynamic, its mean residence time depends on the degree of protection (physical, chemical, biological, and ecological) within the soil matrix. Formation of stable microaggregates and of organo–mineral complexes can protectSOCagainst microbial processes for millennia. In addition to formation of silicatic type of secondary carbonates, leaching of bicarbonates into the subsoil or shallow water table is also an important mechanism of sequestration ofCO2asSIC. Numerous soil functions and ecosystem services depend onSOCand its dynamics. Improvements in soil health, along with increase in availability of water and nutrients, increases soil's resilience against extreme climate events (e.g., drought, heat wave) and imparts disease‐suppressive attributes. Enhancing and sustaining soil health is also pertinent to advancing Sustainable Development Goals of the U.N. such as alleviating poverty, reducing hunger, improving health, and promoting economic development.

Climate change imposes biotic and abiotic stresses on soil and plant health all across the planet. Beneficial rhizobacterial genera, such as Bacillus, Pseudomonas, Paraburkholderia, Rhizobium, Serratia, and others, are gaining popularity due to their ability to provide simultaneous nutrition and protection of plants in adverse climatic conditions. Plant growth-promoting rhizobacteria are known to boost soil and plant health through a variety of direct and indirect mechanisms. However, various issues limit the wider commercialization of bacterial biostimulants, such as variable performance in different environmental conditions, poor shelf-life, application challenges, and our poor understanding on complex mechanisms of their interactions with plants and environment. This study focused on detecting the most recent findings on the improvement of plant and soil health under a stressful environment by the application of beneficial rhizobacteria. For a critical and systematic review story, we conducted a non-exhaustive but rigorous literature survey to assemble the most relevant literature (sorting of a total of 236 out of 300 articles produced from the search). In addition, a critical discussion deciphering the major challenges for the commercialization of these bioagents as biofertilizer, biostimulants, and biopesticides was undertaken to unlock the prospective research avenues and wider application of these natural resources. The advancement of biotechnological tools may help to enhance the sustainable use of bacterial biostimulants in agriculture. The perspective of biostimulants is also systematically evaluated for a better understanding of the molecular crosstalk between plants and beneficial bacteria in the changing climate towards sustainable soil and plant health.

The paper is devoted to the currently relevant problem of achieving sustainable development and minimizing the consequences of climate change by improving soil health. The authors aimed to determine whether improving soil health can enhance agricultural sustainability and resilience to climate change. A theoretical justification is provided for three concepts: soil health, sustainable development goals, and climate change, through an understanding of soil functions. Soil plays a key role in conserving nutrients, regulating water balance, reducing erosion, and mitigating greenhouse gas emissions. An attempt has been made to analyze soil health indicators to understand how they can be influenced to prevent climate change. Depending on the importance and complexity of monitoring soil health indicators, they were divided into three levels of observation. Level I is for baseline indicators that require continuous, more frequent monitoring (e.g., annually): OM and soil moisture content, pH, bulk density, soil texture and structure, visual state, and earthworm count. ІІ level is for more detailed and required laboratory analyses: potentially mineralized nitrogen content, cation exchange capacity, aggregate stability, electrical conductivity, water holding capacity indicators, and microorganism biomass. III level is for highly specialized laboratory research, which is held less frequently: microbial ratio (bacteria : fungi), C : N, soil respiration (CO2 emission), enzyme activity, microbiome genetic analysis, soil fauna biodiversity index, infiltration capacity. Based on the research, we propose addressing the issues of soil health, sustainable development, and climate change mitigation through measures to improve water retention capacity, maintain biodiversity, reduce soil erosion and degradation, and mitigate greenhouse gas emissions from agriculture, as well as adapt agricultural systems. The main thing is that the soil must preserve its functions for future generations. Be that as it may, food security will still be a basic need of all mankind. People will satisfy all other needs only when their biological needs are regular and satisfied.

Higher improvement in soil health by animal-sourced than plant-sourced organic materials through optimized substitution

Sustainable agricultural practices such as reduced tillage and optimized fertilization may have potential to improve soil health and increase availability of plant nutrients and yields. However, there is very little information relating soil quality or health to crop productivity, particularly under farmer management. Therefore, the objective was to investigate the effects of two contrasting approaches to crop fertility management on crop productivity, soil test measurements, and soil enzyme activity as integrative measures of soil health. A three year study was conducted at on-farm sites in Ohio, Illinois, and Iowa where topsoil (0-15 cm) and crop yield of Zea mays L. (corn) and Glycine max. (L.) Merr. (soybean) rotations were collected from two contrasting fertility management systems. The two contrasting approaches tested were the Maximum Farming System (MFSyst) and a more Conventional system (Conv) that differ in approaches to tillage and the frequency of fertilizer applications during the growing season. The MFSyst approach resulted in significantly higher yields, soil nutrient test levels along with β-glucosidase (GLU) and arylsulfatase (ARYL) which are sensitive soil health indicators. Nitrogen use efficiency (NUE) of corn was significantly elevated by nearly 18%, corn yield correlated with GLU activities, and soil test phosphorous (P) levels were reduced by over 50% using the MFSyst approach. These results indicate that improvements in soil health detected by soil GLU and ARYL enzyme activities are associated with significant improvements in soil quality and crop productivity.

Soil health as a proxy for long-term reclamation success of metal-contaminated mine tailings using lime and biosolids

Oilseed crops are major part of human diet providing energy, used for cosmetics, health supplements and other purposes. Intensive agricultural practices, overexploitation of natural resource and climate change pattern have adverse impact on soil health, thus becoming serious concern for oilseed crop production and livelihood security of farmers. Maintenance of soil health with amendments can restore, revitalize and regain the soil quality for sustainable agriculture. Soil amendments, therefore have definite advantage by improving soil health and facilitating nutrient supply to oilseed crops. Soil organic amendments such as animal manure, compost, vermicompost, biosolids/sewage sludge, biochar etc. and inorganic amendments such as gypsum, zeolite, pyrite etc. are the most commonly available amendments which can be directly applied to soil after treatments. Direct and indirect effect of soil amendments on soil chemical, physical and biological properties significantly influences soil-plant-continuum, beneficial for soil health improvement, carbon sequestration and oilseed yield improvement. Soil organic amendments could substitute nearly 25–50% of synthetic fertilizers, enhance nutrient use efficiency and influencing oilseed yield response. Soil amendments may sustain or increase oilseed productivity at reduced production and environmental cost, thus, improve soil health and water use efficiency and its quality, and mitigating climate change impact.

ABSTRACTHealthy soil is critical for ecosystem restoration, climate change mitigation and adaptation, biodiversity conservation, water cycling, farmer livelihoods, and food and nutrition security. Despite its importance, soil health has often been overlooked, but momentum is growing as evidenced by recent high‐level initiatives such as the Nairobi Declaration as part of the Africa Fertiliser and Soil Health Action Plan and the European Union Soil Mission: A Soil Deal for Europe. The UN Decade on Ecosystem Restoration was launched on 5 June 2021 to galvanise local, national and global action to restore degraded ecosystems. In the same year, the UN Food Systems Summit (UNFSS) initiated a call for coalitions of action to champion integrated, systemic approaches to transform food systems. The Coalition of Action 4 Soil Health (CA4SH) was launched to bring soil health into focus with participation across sectors and scales to ultimately raise awareness about this critical ecosystem that we depend on, but which is being degraded at unprecedented rates. Since 2021, CA4SH has grown to include nearly 200 members (as of January 2025) representing the public and private sectors, research institutions, non‐governmental organisations, farmer organisations and cooperatives, individuals, youth‐led organisations, and indigenous organisations to mention some. The initiative has also had a strong focus on gender equity and social inclusion (GESI) in soil and landscape restoration. The Coalition promotes soil as a unifier across a diverse set of stakeholders, building partnerships to overcome critical economic, technical and institutional barriers to the adoption and scaling of healthy soil practices. Furthermore, CA4SH facilitates evidence‐based policy and practice action for the scaling of restoration practices that improve soil health. The Private Sector Guiding Group, launched as part of the UNFSS, developed a call to action to support increased investments in healthy soil, and continues to support the actions of the Coalition. Its four working groups focus on communication, soil health monitoring and implementation, policy, and financial investment. In the first three years since its launch, the Coalition has engaged in multinational dialogues and contributed to the adoption of soil health in the outcomes from the UN Framework Convention of Climate Change (UNFCCC) 27th Conference of the Parties (COP27) through the Koronivia joint work on agriculture (now the Sharm El‐Sheikh Declaration), the UNFCCC COP28 UAE Declaration on Food Systems and Agriculture, the UNCCD COP16 Riyadh Action Agenda and also launched the Soil Health Resolution. Leveraging on the enabling policy environment, the Coalition catalyses public and private sector action with outcomes for economic returns and growth, productivity and rural livelihoods, climate and nature. The positioning of the Coalition in the current global environmental transition is pivotal to drive the multifaceted benefits that soil health improvement offers to food systems transformation and global adaptation to and mitigation of climate change.

Improvements in soil health and soil carbon sequestration by an agroforestry for food production system

In the past decades, dairy farms in eastern Canada have dedicated more land to annual crops and less to perennial forages. Concurrently, there has been a shift in cattle manure management from solid to liquid forms. Our objective was to determine the early response of soil health indicators (soil aggregate stability to water, carbon [C] and nitrogen [N] in microbial biomass, particulate organic matter, and nonfractionated soil) to two crop types (annual crops vs. perennial forages) and N sources (mineral fertilizer, dairy cattle slurry, and biological N fixation) in the 0–10 cm surface soil at three locations (Ontario, Quebec, and Nova Scotia). Despite some variability in their response, most of the indicators pointed to an improvement in soil health within three years of implementation of perennial forages and/or dairy cattle slurry applications. Particulate organic matter and microbial biomass were generally more responsive to the experimental treatments than soil organic matter. Changes in soil C and N were found at the three locations within the first three years of the experiment. For instance, C concentrations were 7%–31% higher under perennial forages and/or dairy cattle slurry in comparison to annual cropping and/or mineral fertilization. Improvement in soil health was generally greater under perennial forages fertilized with dairy cattle slurry, than under annual crops receiving mineral fertilizer. The response of soil C concentration tended to be more pronounced at sites with lower initial soil C concentrations, and faster in the soil with the highest clay content.

Soil health is an old concept receiving renewed attention. Defined as a soil’s capacity to function, soil health is composed of physical, chemical, and biological attributes. The improvement and maintenance of soil health is considered a cornerstone of organic agriculture. Although there are numerous studies that compare organic systems with conventional systems, fewer studies compare organic systems with each other to determine how best to improve soil health metrics. In this review, we focused on nine indicators of soil health (aggregate stability, water holding capacity, infiltration/porosity, erosion/runoff, nutrient cycling, organic carbon, microbial biomass, macrofauna abundance, and weed seed bank). We found 153 peer-reviewed, published studies that measured these soil health indicators in two or more organic treatments. Overall, published research focused on four key practices: (1) cover crops, (2) organic amendments, (3) rotation diversity and length, and (4) tillage. Of these, 26 studies focused on cover crops, 77 on organic amendments, 32 on crop rotations, 40 on tillage, and 22 included more than one practice. Eighty percent of the studies were conducted in the USA and Europe. We found strong agreement in the literature that roll-killed cover crops suppressed weeds better than disking and that weed suppression required high levels of cover crop biomass. Combinations of organic amendments such as composts, manures, and vermicomposts improved soil health metrics compared to when applied alone. Including a perennial crop, like alfalfa, consistently improved soil carbon (C), nitrogen (N), and aggregate stability. Soil health metrics were improved under shallow, non-inversion tillage strategies compared with conventional tillage. Despite their importance for climate change mitigation and adaptation, the effect of practices on aggregate stability and water dynamics were under-studied compared with other soil health metrics. There is a great deal of variety and nuance to organic systems, and future research should focus on how to optimize practices within organic systems to improve and maintain soil health.

The sub‐mountainous tea gardens of the Dooars region of West Bengal, which contribute approximately 25% of the national tea yield, are constantly fighting with diminishing soil fertility. Inorganic alternatives like chemical fertilizers can provide easier yet short‐term solutions, as their prolonged and indiscriminate usage leaches the soil, devouring its productivity, increasing the soil's heavy metal contents, and subsequently accumulating those heavy metals in leaves. A plausible substitution in this scenario could be the use of organic alternatives like composting or biofertilizer. Although references to such alternative means are found in the literature, a holistic approach targeting plant growth promotion along with mitigating soil metal toxicity is lacking. Keeping this background in mind, this pilot study was designed to optimize the dosage of novel biofertilizers (using resident and alien flora) that can reduce heavy metal loads and residual toxicity in soil, thereby improving overall soil health and tea production. Two potential metallophilic plant growth‐promoting strains of Bacillus sp. (previously reported) were selected and applied to potted tea plants of two different varieties of tea: TV9 and TV25. Among the two modes of treatment tested: solid treatment (compost amended with bacterial culture) and liquid treatment (cell pellets mixed in water suspension), the water suspension‐based direct application of resident soil bacteria showed the highest physiological growth with reduced metal toxicity. Based on physiological data and physico‐chemical data collected, it was observed that direct application of bacteria showed better results in both plant and soil health improvement in comparison to regular compost amended with beneficial microflora. Therefore, this small‐scale pilot study aimed to optimize the dosage and mode of application of novel biofertilizers for improved soil and plant health.

Soil health in agricultural ecosystems: Current status and future perspectives