127 research outputs found
On the natural capital and ecosystem services of soils
No full textIn their paper, a framework for the evaluation of the natural capital and ecosystem services of soils, Dominati et al., 2010 E. Dominati, M. Patterson and A. Mackay, A framework for classifying and quantifying the natural capital and ecosystem services of soils, Ecol. Econ. 69 (2010), pp. 1858–1868. Article | PDF (750 K) | View Record in Scopus | Cited By in Scopus (2)Dominati et al. (2010) address the important issue of recognizing the fundamental role of soils within the ecosystems approach (Anon, 2000). Given that conservation organizations and National Governments are adopting the ecosystems approach, as a way of placing value on nature's services to humanity for decision making purposes and policy development, it is critical that frameworks accurately reflect the contributions of all the components of the ecosystem to return a true value; and that we develop the debate on how best to achieve this. Dominati et al. (2010) rightly point out that below ground soil resources are often overlooked, and there is much overlapping terminology between the disciplines of soils, ecology and economics, which can result in confusion over where soils lie within the ecosystems approach
Using microscope observations of thin sections to estimate soil permeability with the Kozeny–Carman equation
No full textOn the Definition of the Natural Capital of Soils: A Framework for Description, Evaluation, and Monitoring
No full textThe unknown consequences and potential impacts of mankind’s ability to destroy, alter, or
manipulate ecosystems on a vast scale drives our need to better understand the earth system.
A fundamental challenge for soil science in the 21st century is to understand the role of
soil processes in relation to the function of the earth system. Th e rationale for developing a
defi nition of soil natural capital stems from the premise that we value ‘things’ based on their
perceived value to human well-being. As a consequence, ignorance of the value of a resource,
or system, may lead to its neglect and omission from decision making. Th erefore, there is a
need to develop a defi nition of soil natural capital, fi tting within a broad framework, which
can be used to assess soil ecosystem services that contribute to the function of the earth
system. Th ough various defi nitions of soil natural capital have been proposed, mostly in the
agricultural context, it still remains a nebulous and ill-defi ned term. Th e objective of this paper
is to develop an embracing defi nition of soil ‘natural capital’ focusing on (i) mass, (ii) energy,
and (iii) organization/entropy. Mass is further subdivided into solid, liquid and gas phases,
and organization into physicochemical, biotic, and spatiotemporal structure. We diff erentiate
between two aspects of capital, the quantity and the quality. As a result of our defi nition, soil
moisture, temperature, and structure emerge as valuable stocks, alongside the more traditionally
viewed stocks such as inorganic (mineralogy, texture) and organic materials (OM content). We
go on to demonstrate how natural capital fi ts within the ecosystem services framework, and
how using integrated valuation and process based models it can be evaluated. Finally we discuss
measurement and monitoring needs that fi t with this vision of evaluation
ChemInform Abstract: Definition of the Natural Capital of Soils: A Framework for Description, Evaluation, and Monitoring
No full textImaging of hill-slope soil moisture wetting patterns in a semi-arid oak savanna catchment using time-lapse electromagnetic induction
No full textSoil moisture (θ) is a fundamental hydrological state variable and its spatial pattern is important for understanding hydrological processes. Determination of small catchment-scale soil moisture status and distribution at intermediate scales (0.01–1 km2) is challenging. Primarily because multi-point measurements using sensors are often impractical, while remote sensing resolution is often too coarse. Geophysical methods, e.g. electromagnetic induction (EMI), offer potential for bridging this gap. Our objective was to test the use of time-lapse EMI surveys to separate the influences of ‘static’ soil variables, e.g. texture/mineralogy, from ‘dynamic’, e.g. changes in soil moisture. A novel differencing approach is used for estimating relative changes in soil moisture, subtracting the bulk soil electrical conductivity (ECa) of the driest seasonal soil map, named the residual ECa, from the ECa collected during subsequent wetting. This approach allows us to remove the effects of spatially distributed mineral electrical surface charge (ECs) and other factors, and improve estimation of water content. Comparing results with TDR determined soil moisture, we improve the correlation from r2 = 0.28 to r2 = 0.48. ECa measurements are observed to be correlated in time (r2 > 0.7), but fall into two distinct groups, corresponding to times before and after the onset of stream flow, supporting the concept of preferred soil moisture states. Catchment wetness index predicts areas of convergence resulting in overland flow and stream flow. However, the spatial pattern of soil moisture does not mirror the wetness index, as others have found. We contend that the use of time-lapse EMI imaging provides important insight into the distribution and dynamics of catchment-scale changes in soil moisture, but acknowledge its limitations of requiring moisture dependent contrast of ECa, which will not occur in some soils
Soil water repellency and pH soil change under tropical pine plantations compared with native tropical forest
No full textIn temperate climates, soil water repellency (SWR) has been documented to develop with land-use change from native forest to pine plantations. In the tropics a sparse evidence base has been documented for the observation of SWR, but no investigation has been conducted to determine the consequences of changing land-use from native forest to pine plantations with regard to SWR. In our research we broaden the evidence base for tropical SWR by comparing the SWR behavior of seven tropical pine plantations in Trinidad with co-located native forest. We found that SWR occurred under both pine and native forest, but was more persistent and less heterogeneous under pine. The SWR was water content dependent with a threshold ~0.2 m3m-3, it showed a linear dependence with litter depth, and it was also found to be higher in more acidic soils. The forest floor pH, contrary to convention for temperate climates, was observed to increase under some pine plantations, as compared with native tropical forest. This only occurred in the very acidic tropical soils (pH<4), but may have important biogeochemical consequences with regard to soil and water quality
Determining Soil-Tree-Grass Relationships in a California Oak Savanna Using Eco-Geophysics
No full textThe effect of total carbon on microscopic soil properties and implications for crop production
No full textSoil structure is a dynamic property affected by physical, chemical, and microbiological processes. Addition of organic matter to soils and the use of different management practices have been reported to impact soil structure and crop production. Moderation in soil temperature and increases in microbial activity and soil water retention are often suggested as reasons for the rise in crop yield when organic matter is added to the soil. Less is known about the direct effect of changes in soil structure on crop production. A field experiment was conducted to study the effect of summer cover crop and in-season management system on soil structure. The experiment was a nested design with summer cover crop as the main plot and management system as the subplot. Summer cover crop treatments included cowpea (Vigna unguiculata L. Walp.) incorporated into the soil in the fall (CI), cowpea used as mulch in the fall (CM), sudangrass (Sorghum vulgare) incorporated into the soil in the fall (S), and dry fallow or bare ground (B). Management systems were organic (ORG) and conventional (CNV) systems. Lettuce (Lactuca sativa L.) and cantaloupes (Cucumis melo L.) were cultivated in rotation in the plots for three consecutive years using the same cover crops and management systems for each plot. Disturbed and undisturbed soil cores were collected at the end of the third year and used for laboratory experiments to measure physical, chemical, and hydraulic properties. Image analysis was used to quantify soil structure properties using a scanning electron microscope on thin sections prepared from the undisturbed soil cores. We found that total soil carbon was corre-lated with porosity, saturation percentage, and pore roughness. Pore roughness was correlated with crop production in general and with marketable production in particular. We found that the higher the complexity of the pore space, the more water retained in the soil, which may increase soil water residence and reduce plant water stress
Author Correction: Phenotype alteration causes long-term changes to the social strategies of victimised birds
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