Restoring Soil Quality to Mitigate Soil Degradation
TL;DR: In this paper, the authors proposed a strategy to minimize soil erosion, create positive organic carbon (SOC) and N budgets, enhance activity and species diversity of soil biota (micro, meso, and macro), and improve structural stability and pore geometry.
Abstract: Feeding the world population, 7.3 billion in 2015 and projected to increase to 9.5 billion by 2050, necessitates an increase in agricultural production of ~70% between 2005 and 2050. Soil degradation, characterized by decline in quality and decrease in ecosystem goods and services, is a major constraint to achieving the required increase in agricultural production. Soil is a non-renewable resource on human time scales with its vulnerability to degradation depending on complex interactions between processes, factors and causes occurring at a range of spatial and temporal scales. Among the major soil degradation processes are accelerated erosion, depletion of the soil organic carbon (SOC) pool and loss in biodiversity, loss of soil fertility and elemental imbalance, acidification and salinization. Soil degradation trends can be reversed by conversion to a restorative land use and adoption of recommended management practices. The strategy is to minimize soil erosion, create positive SOC and N budgets, enhance activity and species diversity of soil biota (micro, meso, and macro), and improve structural stability and pore geometry. Improving soil quality (i.e., increasing SOC pool, improving soil structure, enhancing soil fertility) can reduce risks of soil degradation (physical, chemical, biological and ecological) while improving the environment. Increasing the SOC pool to above the critical level (10 to 15 g/kg) is essential to set-in-motion the restorative trends. Site-specific techniques of restoring soil quality include conservation agriculture, integrated nutrient management, continuous vegetative cover such as residue mulch and cover cropping, and controlled grazing at appropriate stocking rates. The strategy is to produce “more from less” by reducing losses and increasing soil, water, and nutrient use efficiency.
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National University of Cordoba1, Leipzig University2, Helmholtz Centre for Environmental Research - UFZ3, Indiana University4, United Nations5, University of the West Indies6, Karlsruhe Institute of Technology7, National Autonomous University of Mexico8, University of Minnesota9, BirdLife International10, University of Cambridge11, University of British Columbia12, National University of Río Negro13, Chiba University14, National Institute for Environmental Studies15, Michigan State University16, United Nations University17, International Institute of Minnesota18, Stellenbosch University19, Simón Bolívar University20, Commonwealth Scientific and Industrial Research Organisation21, Hungarian Academy of Sciences22, University of Queensland23, Duke University24, Natural History Museum25, Imperial College London26, University of the West of England27, Stockholm University28, Clark University29, University of Cape Town30, IFREMER31, Radboud University Nijmegen32, George Mason University33, University of Oxford34, Royal Botanic Gardens35, University of the Philippines Diliman36
TL;DR: The first integrated global-scale intergovernmental assessment of the status, trends, and future of the links between people and nature provides an unprecedented picture of the extent of the authors' mutual dependence, the breadth and depth of the ongoing and impending crisis, and the interconnectedness among sectors and regions.
Abstract: The human impact on life on Earth has increased sharply since the 1970s, driven by the demands of a growing population with rising average per capita income. Nature is currently supplying more materials than ever before, but this has come at the high cost of unprecedented global declines in the extent and integrity of ecosystems, distinctness of local ecological communities, abundance and number of wild species, and the number of local domesticated varieties. Such changes reduce vital benefits that people receive from nature and threaten the quality of life of future generations. Both the benefits of an expanding economy and the costs of reducing nature's benefits are unequally distributed. The fabric of life on which we all depend-nature and its contributions to people-is unravelling rapidly. Despite the severity of the threats and lack of enough progress in tackling them to date, opportunities exist to change future trajectories through transformative action. Such action must begin immediately, however, and address the root economic, social, and technological causes of nature's deterioration.
913 citations
TL;DR: In this article, the economic feasibility of biochar application cannot be neglected and strategies for reducing biochar losses and its application costs, and increasing its use efficiency need to be developed.
534 citations
TL;DR: In this article, a review of 634 publications on biochar and biochar-compost mixtures as soil amendments is presented to identify the potential gaps in our understanding of the role of these amendments in agriculture.
452 citations
TL;DR: In this paper, the authors discuss the importance of preserving soil capital and its relationship to human civilization and food security, and discuss trends concerning the availability of arable agricultural land, different scenarios, and their limitations, analyzed and discussed.
Abstract: Soil health, along with water supply, is the most valuable resource for humans, as human life depends on the soil’s generosity. Soil degradation, therefore, poses a threat to food security, as it reduces yield, forces farmers to use more inputs, and may eventually lead to soil abandonment. Unfortunately, the importance of preserving soil health appears to be overlooked by policy makers. In this paper, I first briefly introduce the present situation concerning agricultural production, natural resources, soil degradation, land use and the challenge ahead, to show how these issues are strictly interwoven. Then, I define soil degradation and present a review of its typologies and estimates at a global level. I discuss the importance of preserving soil capital, and its relationship to human civilization and food security. Trends concerning the availability of arable agricultural land, different scenarios, and their limitations, are analyzed and discussed. The possible relation between an increase in a country’s GNP, population and future availability of arable land is also analyzed, using the World Bank’s database. I argue that because of the many sources of uncertainty in the data, and the high risks at stake, a precautionary approach should be adopted when drawing scenarios. The paper ends with a discussion on the key role of preserving soil organic matter, and the need to adopt more sustainable agricultural practices. I also argue that both our relation with nature and natural resources and our lifestyle need to be reconsidered.
350 citations
Cites background from "Restoring Soil Quality to Mitigate ..."
...Soil degradation, therefore, refers to a broad spectrum of changes in soil characteristics because of natural or anthropogenic factors that alter their structure and quality, including deforestation and the removal of natural vegetation, agricultural activities, overgrazing, overexploitation of vegetation for domestic use, and industrial activities [7,14,18,19,76,77]....
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...This in turn reduces crop productivity, resulting in the need for more fertilization and irrigation, making soils a net source of CO2 emissions [5,16,20,77,86,99,124,200,201]....
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TL;DR: Information gathered from this review suggests that biochar amendment is a viable way of improving the quality of problem soils and enhancing crop production.
337 citations
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TL;DR: In this article, the carbon sink capacity of the world’s agricultural and degraded soils is 50 to 66% of the historic carbon loss of 42 to 78 gigatons of carbon.
Abstract: :The carbon sink capacity of the world’s agricultural and degraded soils is 50 to 66% of the historic carbon loss of 42 to 78 gigatons of carbon. The rate of soil organic carbon sequestration with adoption of recommended technologies depends on soil texture and structure, rainfall, temperature, farming system, and soil management. Strategies to increase the soil carbon pool include soil restoration and woodland regeneration, no-till farming, cover crops, nutrient management, manuring and sludge application, improved grazing, water conservation and harvesting, efficient irrigation, agroforestry practices, and growing energy crops on spare lands. An increase of 1 ton of soil carbon pool of degraded cropland soils may increase crop yield by 20 to 40 kilograms per hectare (kg/ha) for wheat, 10 to 20 kg/ha for maize, and 0.5 to 1 kg/ha for cowpeas. As well as enhancing food security, carbon sequestration has the potential to offset fossilfuel emissions by 0.4 to 1.2 gigatons of carbon per year, or 5 to 15% of the global fossil-fuel emissions.
5,835 citations
"Restoring Soil Quality to Mitigate ..." refers background in this paper
..., South Asia), is severely depleted by over-exploitation of natural resources [23]....
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TL;DR: In this article, the effectiveness of various binding agents at different stages in the structural organization of aggregates is described and forms the basis of a model which illustrates the architecture of an aggregate.
Abstract: Summary
The water-stability of aggregates in many soils is shown to depend on organic materials. The organic binding agents have been classified into (a) transient, mainly polysaccharides, (b), temporary, roots and fungal hyphae, and (c) persistent, resistant aromatic components associated with polyvalent metal cations, and strongly sorbed polymers. The effectiveness of various binding agents at different stages in the structural organization of aggregates is described and forms the basis of a model which illustrates the architecture of an aggregate. Roots and hyphae stabilize macro-aggregates, defined as > 250 μm diameter; consequently, macroaggregation is controlled by soil management (i.e. crop rotations), as management influences the growth of plant roots, and the oxidation of organic carbon. The water-stability of micro-aggregates depends on the persistent organic binding agents and appears to be a characteristic of the soil, independent of management.
5,389 citations
"Restoring Soil Quality to Mitigate ..." refers background in this paper
...Increases in soil biodiversity, MBC and activity of earthworms and termites can all improve aggregation and encapsulate C within stable micro-aggregates as outlined in the hierarchy concept [47]....
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TL;DR: With the addition of a quarter of a million people each day, the world population's food demand is increasing at a time when per capita food productivity is beginning to decline.
Abstract: Soil erosion is a major environmental threat to the sustainability and productive capacity of agriculture. During the last 40 years, nearly one-third of the world's arable land has been lost by erosion and continues to be lost at a rate of more than 10 million hectares per year. With the addition of a quarter of a million people each day, the world population's food demand is increasing at a time when per capita food productivity is beginning to decline.
2,589 citations
"Restoring Soil Quality to Mitigate ..." refers background in this paper
...Reductions in plant cover caused by over-grazing and the trampling effect can degrade soil structure, reduce water infiltration, increase runoff, aggravate soil erosion, and cause severe economic losses [76]....
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TL;DR: The Soil Science Society of America (SSSA) Ad Hoc Committee on Soil Quality (S-581) as mentioned in this paper defined soil quality as "the capacity (of soil) to function".
Abstract: This essay summarizes deliberation by the Soil Science Society of America (SSSA) Ad Hoc Committee on Soil Quality (S-581) and was written to spur discussion among SSSA members Varying perceptions of soil quality have emerged since the concept was suggested in the early 1990s, and dialogue among members is important because, unlike air and water quality, legislative standards for soil quality have not been and perhaps should not be defined In simplest terms, soil quality is “the capacity (of soil) to function” This definition, based on function, reflects the living and dynamic nature of soil Soil quality can be conceptualized as a three-legged stool, the function and balance of which requires an integration of three major components — sustained biological productivity, environmental quality, and plant and animal health The concept attempts to balance multiple soil uses (eg, for agricultural production, remediation of wastes, urban development, forest, range, or recreation) with goals for environmental quality Assessing soil quality will require collaboration among all disciplines of science to examine and interpret their results in the context of land management strategies, interactions, and trade-offs Society is demanding solutions from science Simply measuring and reporting the response of an individual soil parameter to a given perturbation or management practice is no longer sufficient The soil resource must be recognized as a dynamic living system that emerges through a unique balance and interaction of its biological, chemical, and physical components We encourage SSSA members to consider the concept of soil quality (perhaps as a marketing tool) and to debate how it might enable us to more effectively meet the diverse natural resource needs and concerns of our rural, urban, and suburban clientele of today and tomorrow
1,804 citations
TL;DR: The Bachelor of Science in Sustainability as discussed by the authors provides the broad fundamental knowledge, skills and competencies needed to drive sustainable outcomes that address today's urgent environmental, economic and social challenges.
Abstract: Sustainability seeks a way for human and natural systems to work together so that all species can survive and thrive over the long term, both locally and globally. The Bachelor of Science in Sustainability provides the broad fundamental knowledge, skills and competencies needed to drive sustainable outcomes that address today's urgent environmental, economic and social challenges. This degree can be applied across a wide range of fields, from management, design and planning to environmental services in business, nonprofit and public institutions.
1,591 citations