Main concepts of soil ecology
Abstract
Soil ecology is the study of regular correlations between the soil and its environment. These ecological correlations are disclosed by the establishment of certain quantitative dependencies in the exchanges of matter and energy in the soil-environment system, in the finding of conjugated soil-factor series, in the elucidation of gradient changes between the composition of soil and environmental elements, in the disclosure of laws for the variety of soils as connection with environment factors and last in the establishment of qualitatively peculiar type combinations of environmental factors leading to certain types of soil formation.
References (5)
- E. Ehwald
On the interrelations of investigations in the genesis and ecology of soils
Pochvovedenie
(1972) - H. Jenny
Factors of Soil Formation
Cited by (13)
Soil is a hierarchical, self-organizing, and emergent system that supports plant and microbial growth, enables carbon sequestration, facilitates water fluxes, and provide habitat for microorganisms, all of which depend on soil structure. Recent debates have generally reduced soil functioning to geometry and topology of soil solids and pores and denied the existence and role of soil aggregates and hierarchy of solids. Here we argue that soil structure has a dual nature that essentially boils down to the interlocking of pores and solids in groupings of specific complexity and dynamics called aggregates. By comparing their architectural, chemical, and energetic parameters, we conclude that aggregates have a much higher information density than pores. Therefore, aggregates (as unity of solids and pores) perform much broader range of functions compared to pores alone, especially in long-term. A set of soil functions corresponding to each level of the soil structure hierarchy depends on aggregate type (macroaggregates, water-stable aggregates, microaggregates, and elementary soil particles) determined by their specific binding energy, dynamics, and lifetime. The introduced here energy-based concept justifies the hierarchy of soil structure, and is the base for the soil structuring and carbon stabilization processes in their most general form. We understand the soil structure implying the energy-based approach: each hierarchy level corresponds to specific bonding strength of mineral and organic particles forming aggregates. Aggregate formation is a bottom-up process because the energy binding elementary soil particles and microaggregates is orders of magnitude higher than that gluing macroaggregates. The duality of soil structure is manifested not only in the relationship between pores and solids in aggregates, but also in the interactions and competition between the biological and non-biological processes that aggregate and disaggregate the structure. The view of the pore space as a transport pathway and habitat for soil living phase and plant roots, the solid-pore interface as a setting for physico-chemical and biological transformations, and aggregates as a result of these phenomena, provides a context for mechanistic understanding and process-based modeling of soil functions and health.
Modelling pedogenesis of Technosols
2016, GeodermaCitation Excerpt :The factorial approach is phenomenological and statistically based. As it is empirical, the factorial approach does not demonstrate the relationship between the factors and the formed soil nor does it explicitly describe the processes that occur and their feedback (Jenny, 1958; Volobuyev, 1974). The range of validity of factorial models depends on the quality and size of the input data set (Silberstein, 2006).
Technosols, soils subjected to a strong human influence and containing significant amounts of artefacts, are characteristic of the Anthropocene. In order to better apprehend their growing importance in our current environment, our knowledge of the evolution and fate of these soils must be improved. The aim of this article is to promote pedogenic modelling for Technosols by proposing an appropriate framework. The paper first defines the characteristics of Technosol pedogenesis, and then considers the requirements for its modelling in light of general concepts of pedogenesis, modelling tools and techniques, and 18 selected existing quantitative models. This mixed technical and conceptual analysis allows us to address at once the modelling approach, the choice of processes, the integration of control variables, the time scales, the spatial representation, and the data needed for such a framework. Technosol pedogenesis is characterised by the soils' anthropic creation, a young age, a climate globally favourable for soil evolution, a surprising level of biological activity, and mostly reactive artefacts as parent materials. Pedogenic processes observed in Technosols are similar to those occurring in more natural soils; however, they generally have fast kinetics and occur in unusual assemblages. We propose that the modelling framework for Technosol evolution should be based on the coupling of process-based models of soil functioning processes and accommodate the peculiar properties of technogenic materials. Our work also highlights modelling features needed for pedogenesis in general: development of biological and physical models, selection of a comprehensive energy unit, dual-time scale modelling, and multi-scale representation of the soil profile. We propose (i) an adaptation of existing energy metrics (entropy, exergy, emergy or EEMT), (ii) a dual-time scale approach, our original concept, based on resilience patterns in soil changes, and (iii) the development of an existing spatial representation. Constructed Technosols are a relevant experimental model which supplies reliable data on soil evolution, data which are required for the development of pedogenic models. Technosols are emblematic of the issues we face for the management of the soils of the Anthropocene. The design of a modelling framework for Technosol evolution should therefore bring interesting developments for pedogenic modelling in general.
Geomorphological impacts of a tornado disturbance in a subtropical forest
2015, CatenaCitation Excerpt :In recent years there have been several attempts to develop a more explicit incorporation of the biological energy “subsidy” to pedological and geomorphological processes. Volobuyev (1964, 1974) made important early contributions, but these were largely ignored until recently (c.f. Rasmussen et al., 2005, 2011; Rasmussen and Tabor, 2007; Minasny et al., 2008; Phillips, 2009a). Geomorphologists have also increasingly recognized the important biomechanical effects of vegetation.
We studied tree uprooting associated with an EF2 tornado that touched down in portions of the Ouachita Mountains in western Arkansas in 2009. In the severe blowdown areas all trees in the mixed shortleaf pine–hardwood forest were uprooted or broken, with no relationship between tree species or size and whether uprooting or breakage occurred. There was also no significant relationship between tree species and amount of soil displaced, and only a weak relationship between tree size and rootwad size. Uprooting resulted in a mean bioturbation rate of 205 m3 ha− 1 (about 240 t ha− 1). Direct transfer of wind energy via tree uprooting to geomorphic work of soil displacement was about 75 to 190 J m− 2. Given the infrequency of tornadoes, this energy subsidy is minor with respect to the long-term energetics of pedogenesis and landscape evolution. However, it does represent a highly significant pulse of geomorphically-significant energy relative to other mechanical processes. Tornadoes such as that of April, 2009—not atypical for the region—are disturbances causing severe, non-selective impacts within the affected area. At a broader, landscape scale, tornadoes are highly localized disturbances, and occur infrequently within any given landform element or forest stand. Only about a third of the uproots revealed root penetration of bedrock, compared to about 90% in other areas of the Ouachita Mountains. This is attributable to the thicker colluvial soils at the study site, and is consistent with the idea that root–bedrock interaction is more likely in thinner regolith covers.
The role of climate-driven chemical weathering on soil production
2014, GeomorphologyClimate plays an important role in controlling rates of weathering and weathered regolith production. Regolith production functions, however, seldom take climate parameters into account. Based on a climate-dependent weathered regolith production model, at low denudation rates, relative regolith thicknesses are less sensitive to changes in precipitation rates, while at high denudation rates, small changes in climatic parameters can result in complete stripping of hillslopes. This pattern is compounded by the long residence times and system response times associated with low denudation rates, and vice versa. As others have shown, the transition between regolith-mantled and bedrock slopes is dependent on the ratio of denudation to production. Here, we further suggest that this is itself a function of precipitation rate and temperature. We suggest that climatic parameters can be easily incorporated into existing soil production models and that such additions improve the predictive power of soil production models.
Advances in Agronomy Quantifying Processes of Pedogenesis
2011, Advances in AgronomyOur knowledge of plant and animal growth and development is far superior to that of the evolution of soil, yet soil plays a fundamental role in natural ecosystems. To understand the complexity of soil systems, we need to explore processes that lead to its formation. Research in pedogenesis has been focused on formalizing soil-forming factors and processes to ultimately model soil formation in the landscape. Early models described soil formation qualitatively and were mostly limited to a description of soil evolution in the landscape. They led to the development of qualitative models of pedogenesis based on empirical observations and later to quantitative models of pedogenesis based on empirical equations or detailed differential equations derived from fundamental physics. This review highlights the main models of pedogenesis and focuses on models and rates of pedogenic processes such as the production of soil from weathering of parent materials and vertical and lateral movements in the soil profile. It will become clear that field and laboratory work is needed to improve and validate quantitative models of pedogenesis. In order to estimate and verify model parameters, it is therefore of importance to collect real-world data.
Quantifying Processes of Pedogenesis
2011, Advances in AgronomyScientific institutions all over the world emphasize the importance of effective links between science and society when pursuing sustainable development thereby linking science and development. Unfortunately, the knowledge paradox implies that too much research is not applied, partly because the research community is still rather inward looking, creating a gap between what is written and what is achieved in practice. The Dutch government initiated, therefore, the large 6-year TransForum program to enhance innovation in agriculture, not allowing the regular research circuit to set the agenda. TransForum emphasized the relevance of connected value development when dealing with wicked problems associated with sustainable development, requiring a balance between the well-known people, planet, and profit aspects of sustainable development. Thus new and innovative 3P businesses were created through the sequence of value proposition, -creation, and -capture, together constituting connected value development. This required transdisciplinary interaction between knowledge institutions, entrepreneurs, nongovernmental organizations (NGOs), and governmental bodies working together on innovation (KENGi partners), each of these partners contributing different opinions, goals, and values. In this chapter, four case studies are used to illustrate that innovation was achieved by successively working together on value proposition, -creation, and -capture. Only the committed persistence of entrepreneurs supported by knowledge brokers and development of new business and organizational models ultimately led to the desired connected value development, representing a successful link between knowledge creation and societal appreciation. The process involved mobilization and strategic injection of various forms of tacit and scientific knowledge in the overall interaction process that often took more than 10 years to mature, requiring an important role for knowledge brokers with hard knowledge and social intelligence (“T-shaped skills”) as well as long-term funding. The development of value propositions needed much more attention than is usually provided. Research planning and management procedures as well as judgement procedures need to be adapted to fit transdisciplinary requirements. The cases demonstrate that the process of connected value development is unique for each project; there is no standard recipe. Track records of case studies, as presented, can be used in education as a learning tool to create awareness for possible opportunities as well as pitfalls in transdisciplinary studies.