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Bob Ahrens - One of the best experts on this subject based on the ideXlab platform.
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new developments in Soil classification world reference base for Soil Resources
Geoderma, 2000Co-Authors: Freddy O. F. Nachtergaele, O Spaargaren, Bob AhrensAbstract:It has been a matter of great concern that after hundred years of modern Soil science a generally accepted system of Soil classification has not yet been universally adopted [Dudal, R., 1990. Progress in IRB preparation. In: Rozanov, B.G. (Ed.), Soil Classification. Reports of the International Conference on Soil Classification, 12–16 September 1988, Alma-Ata, USSR. Centre for International Projects, USSR State Committee for Environmental Protection, Moscow. pp. 69–70]. This situation arises partly from the fact that Soils constitute a continuum, which unlike easily identifiable plants and animals, needs to be placed into classes by convention. In order to remedy this the International Union of Soil Science has been working for the last 20 years with a working group RB, to develop a common language for naming the Soils of the world: the World Reference Base for Soil Resources (WRB), which was endorsed by the IUSS World Congress at Montpellier in 1998. This paper reflects on the WRB, its objectives, its principles, goals as well as its implementation. Last but not least, projections are made on implications of WRB for Soil inventories and small-scale land surveys.
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new developments in Soil classification world reference base for Soil Resources
Geoderma, 2000Co-Authors: Freddy O. F. Nachtergaele, O Spaargaren, Jozef Deckers, Bob AhrensAbstract:It has been a matter of great concern that after hundred years of modern Soil science a generally accepted system of Soil classification has not yet been universally adopted [Dudal, R., 1990. Progress in IRB preparation. In: Rozanov, B.G. (Ed.), Soil Classification. Reports of the International Conference on Soil Classification, 12–16 September 1988, Alma-Ata, USSR. Centre for International Projects, USSR State Committee for Environmental Protection, Moscow. pp. 69–70]. This situation arises partly from the fact that Soils constitute a continuum, which unlike easily identifiable plants and animals, needs to be placed into classes by convention. In order to remedy this the International Union of Soil Science has been working for the last 20 years with a working group RB, to develop a common language for naming the Soils of the world: the World Reference Base for Soil Resources (WRB), which was endorsed by the IUSS World Congress at Montpellier in 1998. This paper reflects on the WRB, its objectives, its principles, goals as well as its implementation. Last but not least, projections are made on implications of WRB for Soil inventories and small-scale land surveys.
O Spaargaren - One of the best experts on this subject based on the ideXlab platform.
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harmonisation of the Soil map of africa at the continental scale
Geoderma, 2013Co-Authors: Olivier Dewitte, O Spaargaren, Henrik Breuningmadsen, Arwyn Jones, Michel Brossard, A Dampha, Jozef Deckers, T Gallali, Stephen H Hallett, Robert J A JonesAbstract:In the context of major global environmental challenges such as food security, climate change, fresh water scarcity and biodiversity loss, the protection and the sustainable management of Soil Resources in Africa are of paramount importance. To raise the awareness of the general public, stakeholders, policy makers and the science community to the importance of Soil in Africa, the Joint Research Centre of the European Commission has produced the Soil Atlas of Africa. To that end, a new harmonised Soil map at the continental scale has been produced. The steps of the construction of the new area-class map are presented, the basic information being derived from the Harmonized World Soil Database (HWSD). We show how the original data were updated and modified according to the World Reference Base for Soil Resources classification system. The corrections concerned boundary issues, areas with no information, Soil patterns, river and drainage networks, and dynamic features such as sand dunes, water bodies and coastlines. In comparison to the initial map derived from HWSD, the new map represents a correction of 13% of the Soil data for the continent. The map is available for downloading.
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new developments in Soil classification world reference base for Soil Resources
Geoderma, 2000Co-Authors: Freddy O. F. Nachtergaele, O Spaargaren, Bob AhrensAbstract:It has been a matter of great concern that after hundred years of modern Soil science a generally accepted system of Soil classification has not yet been universally adopted [Dudal, R., 1990. Progress in IRB preparation. In: Rozanov, B.G. (Ed.), Soil Classification. Reports of the International Conference on Soil Classification, 12–16 September 1988, Alma-Ata, USSR. Centre for International Projects, USSR State Committee for Environmental Protection, Moscow. pp. 69–70]. This situation arises partly from the fact that Soils constitute a continuum, which unlike easily identifiable plants and animals, needs to be placed into classes by convention. In order to remedy this the International Union of Soil Science has been working for the last 20 years with a working group RB, to develop a common language for naming the Soils of the world: the World Reference Base for Soil Resources (WRB), which was endorsed by the IUSS World Congress at Montpellier in 1998. This paper reflects on the WRB, its objectives, its principles, goals as well as its implementation. Last but not least, projections are made on implications of WRB for Soil inventories and small-scale land surveys.
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new developments in Soil classification world reference base for Soil Resources
Geoderma, 2000Co-Authors: Freddy O. F. Nachtergaele, O Spaargaren, Jozef Deckers, Bob AhrensAbstract:It has been a matter of great concern that after hundred years of modern Soil science a generally accepted system of Soil classification has not yet been universally adopted [Dudal, R., 1990. Progress in IRB preparation. In: Rozanov, B.G. (Ed.), Soil Classification. Reports of the International Conference on Soil Classification, 12–16 September 1988, Alma-Ata, USSR. Centre for International Projects, USSR State Committee for Environmental Protection, Moscow. pp. 69–70]. This situation arises partly from the fact that Soils constitute a continuum, which unlike easily identifiable plants and animals, needs to be placed into classes by convention. In order to remedy this the International Union of Soil Science has been working for the last 20 years with a working group RB, to develop a common language for naming the Soils of the world: the World Reference Base for Soil Resources (WRB), which was endorsed by the IUSS World Congress at Montpellier in 1998. This paper reflects on the WRB, its objectives, its principles, goals as well as its implementation. Last but not least, projections are made on implications of WRB for Soil inventories and small-scale land surveys.
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world reference base for Soil Resources
Encyclopedia of Soil Science, 1998Co-Authors: Jozef Deckers, Freddy O. F. Nachtergaele, P Driessen, O SpaargarenAbstract:In 1998, the International Union of Soil Sciences (IUSS) officially adopted the world reference base for Soil Resources (WRB) as the Union's system for Soil correlation. The structure, concepts, and definitions of the WRB are strongly influenced by the FAO-UNESCO legend of the Soil map of the world (1-2). At the time of itsinception, the WRB proposed 30 "Soil Reference Groups" accommodating more than 200 ("second level") Soil units. WRB (3-5) was endorsed by the IUSS in 1998 and provides an opportunity to create and refine a common and global language for Soil classification. WRB aims to serve as a framework through which ongoing Soil classification throughout the world can be harmonized. The ultimate objective is to reach international agreement on the major Soil groups to be recognized at a global scale as well as on the criteria and methodology to be applied for defining and separating them. Such an agreement is needed to facilitate the exchange of information and experience, to provide a common scientific language, to strengthen the applications of Soil science, and to enhance the communication with other disciplines and make the major Soil names into household names
Freddy O. F. Nachtergaele - One of the best experts on this subject based on the ideXlab platform.
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new developments in Soil classification world reference base for Soil Resources
Geoderma, 2000Co-Authors: Freddy O. F. Nachtergaele, O Spaargaren, Bob AhrensAbstract:It has been a matter of great concern that after hundred years of modern Soil science a generally accepted system of Soil classification has not yet been universally adopted [Dudal, R., 1990. Progress in IRB preparation. In: Rozanov, B.G. (Ed.), Soil Classification. Reports of the International Conference on Soil Classification, 12–16 September 1988, Alma-Ata, USSR. Centre for International Projects, USSR State Committee for Environmental Protection, Moscow. pp. 69–70]. This situation arises partly from the fact that Soils constitute a continuum, which unlike easily identifiable plants and animals, needs to be placed into classes by convention. In order to remedy this the International Union of Soil Science has been working for the last 20 years with a working group RB, to develop a common language for naming the Soils of the world: the World Reference Base for Soil Resources (WRB), which was endorsed by the IUSS World Congress at Montpellier in 1998. This paper reflects on the WRB, its objectives, its principles, goals as well as its implementation. Last but not least, projections are made on implications of WRB for Soil inventories and small-scale land surveys.
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new developments in Soil classification world reference base for Soil Resources
Geoderma, 2000Co-Authors: Freddy O. F. Nachtergaele, O Spaargaren, Jozef Deckers, Bob AhrensAbstract:It has been a matter of great concern that after hundred years of modern Soil science a generally accepted system of Soil classification has not yet been universally adopted [Dudal, R., 1990. Progress in IRB preparation. In: Rozanov, B.G. (Ed.), Soil Classification. Reports of the International Conference on Soil Classification, 12–16 September 1988, Alma-Ata, USSR. Centre for International Projects, USSR State Committee for Environmental Protection, Moscow. pp. 69–70]. This situation arises partly from the fact that Soils constitute a continuum, which unlike easily identifiable plants and animals, needs to be placed into classes by convention. In order to remedy this the International Union of Soil Science has been working for the last 20 years with a working group RB, to develop a common language for naming the Soils of the world: the World Reference Base for Soil Resources (WRB), which was endorsed by the IUSS World Congress at Montpellier in 1998. This paper reflects on the WRB, its objectives, its principles, goals as well as its implementation. Last but not least, projections are made on implications of WRB for Soil inventories and small-scale land surveys.
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world reference base for Soil Resources
Encyclopedia of Soil Science, 1998Co-Authors: Jozef Deckers, Freddy O. F. Nachtergaele, P Driessen, O SpaargarenAbstract:In 1998, the International Union of Soil Sciences (IUSS) officially adopted the world reference base for Soil Resources (WRB) as the Union's system for Soil correlation. The structure, concepts, and definitions of the WRB are strongly influenced by the FAO-UNESCO legend of the Soil map of the world (1-2). At the time of itsinception, the WRB proposed 30 "Soil Reference Groups" accommodating more than 200 ("second level") Soil units. WRB (3-5) was endorsed by the IUSS in 1998 and provides an opportunity to create and refine a common and global language for Soil classification. WRB aims to serve as a framework through which ongoing Soil classification throughout the world can be harmonized. The ultimate objective is to reach international agreement on the major Soil groups to be recognized at a global scale as well as on the criteria and methodology to be applied for defining and separating them. Such an agreement is needed to facilitate the exchange of information and experience, to provide a common scientific language, to strengthen the applications of Soil science, and to enhance the communication with other disciplines and make the major Soil names into household names
Jonathan P. Lynch - One of the best experts on this subject based on the ideXlab platform.
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Plant phenology: a critical controller of Soil resource acquisition
Journal of experimental botany, 2009Co-Authors: Eric A. Nord, Jonathan P. LynchAbstract:Plant phenology, the timing of plant growth and development, is changing in response to global climate change. Changing temperature, Soil moisture, nitrogen availability, light, and elevated CO(2) are all likely to affect plant phenology. Alteration of plant phenology by global climate change may alter the ability of plants to acquire Soil Resources (water and nutrients) by altering the timing and duration of the deployment of roots and leaves, which drive resource acquisition. The potential importance of phenologically-driven changes in Soil resource acquisition for plant fitness and productivity have received little attention. General hypotheses are proposed for how plant acquisition of Soil Resources may be affected by the alteration of phenology. It is expected that the acquisition of mobile Resources will be approximately proportional to total transpiration. Alteration of phenology that increases total transpiration should increase, while changes in phenology that reduce transpiration should decrease the acquisition of mobile Resources. The acquisition of immobile Resources will be approximately proportional to root length duration, thus changes in phenology that increase growth duration should increase the acquisition of immobile Resources and vice versa. For both groups of Resources, longer growing seasons would tend to increase resource acquisition, and shorter growing seasons would tend to decrease resource acquisition. In the case of Resources that exhibit seasonal variability in availability, the synchrony of resource availability and acquisition capacity is important, and subject to disturbance by the alteration of phenology.
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root architecture and plant productivity
Plant Physiology, 1995Co-Authors: Jonathan P. LynchAbstract:Water and nutrient availability limit plant growth in a11 but a very few natural ecosystems. They limit yield in most agricultural ecosystems, and in the United States and other industrialized nations, intensive irrigation and fertilization have generated serious environmental problems. The acquisition of Soil Resources by plant root systems is therefore a subject of considerable interest in agriculture and ecology, as well as a complex and challenging problem in basic plant biology. Symbioses between roots and otlier organisms (notably mycorrhizas and N-fixing bacteria), modification of the rhizosphere through root exudates, and the uptake and transport characteristics of root axes are a11 important dimensions of this problem that are being actively researched by plant biologists. Another aspect of this problem that has received less attention, despite its probable importance, is root architecture. Recent methodological innovations present opportunities for improved under.standing of the functional importance of root architecture in the efficient acquisition of Soil Resources and plant adaptation to suboptimal Soil conditions. The purpose of this Update is to briefly summarize conceptual issues and recent developments in the study of root architecture and to propose a framework for understanding its physiological basis.
Richard K Kobe - One of the best experts on this subject based on the ideXlab platform.
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neighbour interactions strengthen with increased Soil Resources in a northern hardwood forest
Journal of Ecology, 2011Co-Authors: Thomas W Baribault, Richard K KobeAbstract:Summary 1. The relationship between Soil resource availability and competitive interactions remains unclear in forest ecosystems. If competition shifts from below-ground to above-ground across Soil resource gradients, then competitive interactions should constrain growth across Soil fertility levels. Alternatively, competition may be less important under stressful conditions associated with low Soil Resources. 2. We developed individual-based growth models as functions of local tree neighbourhood and measurements of Soil Resources for 10 common tree species from sites established across a Soil resource gradient in north-west Lower Michigan, USA. We hypothesized that tree growth should increase with Soil resource availability (rarely measured at local scales), but decrease with the density, size and proximity of neighbouring trees. 3. Correlations of growth to neighbourhood effects were strongest for species occupying primarily high-resource sites. Correlations of growth to Soil Resources were positive for species associated with high and intermediate fertility. In contrast, correlations of growth to Soil water were negative for species associated with low fertility, suggesting that competitiveness of these species decreased with higher Soil Resources and concomitant decreases in irradiance. 4. Relationships between mean site-level tree growth and Soil Resources were much stronger than individual growth–local resource relationships. Weaker species-specific, individual-level trends likely arose from limited species distributions across each Soil resource domain. 5. Synthesis. Neighbourhood interactions were more prevalent in species associated with high Soil fertility sites, where canopy transmission of irradiance was low. For species dominant at low fertility, where canopy transmission of irradiance was relatively high, neighbourhood interactions were absent or negligible. The growth of intermediate-fertility species was negatively correlated with Soil water, but decreasing site-level canopy openness with Soil water suggests that these species were out-competed for irradiance as Soil Resources increased. Thus, irradiance likely mediated the stronger competitive interactions at higher-fertility sites.
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seedling growth responses to Soil Resources in the understory of a wet tropical forest
Ecology, 2011Co-Authors: Ellen K Holste, Richard K Kobe, Corine VriesendorpAbstract:Plant growth responses to Resources may be an important mechanism that influences species' distributions, coexistence, and community structure. Irradiance is considered the most important resource for seedling growth in the understory of wet tropical forests, but multiple Soil nutrients and species have yet to be examined simultaneously with irradiance under field conditions. To identify potentially limiting Resources, we modeled tree seedling growth as a function of irradiance and Soil nutrients across five sites, spanning a Soil fertility gradient in old-growth, wet tropical forests at La Selva Biological Station, Costa Rica. We measured an array of Soil nutrients including total nitrogen (total N), inorganic N (nitrate [NO3−] and ammonium [NH4+]), phosphate (PO4−), and sum of base cations (SBC; potassium, magnesium, and calcium). Shade in the forest understory did not preclude seedling growth correlations with Soil nutrients. Irradiance was a significant predictor of growth in 52% of the species, inorg...
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sapling growth as a function of light and landscape level variation in Soil water and foliar nitrogen in northern michigan
Oecologia, 2006Co-Authors: Richard K KobeAbstract:Interspecific differences in sapling growth responses to Soil Resources could influence species distributions across Soil resource gradients. I calibrated models of radial growth as a function of light intensity and landscape-level variation in Soil water and foliar N for saplings of four canopy tree species, which differ in adult distributions across Soil resource gradients. Model formulations, characterizing different resource effects and modes of influencing growth, were compared based on relative empirical support using Akaike's Information Criterion. Contrary to expectation, the radial growth of species associated with lower fertility (Acer rubrum and Quercus rubra) was more sensitive to variation in Soil Resources than the high fertility species Acer saccharum. Moreover, there was no species tradeoff between growth under high foliar N versus growth under low foliar N, which would be expected if growth responses to foliar N mediated distributions. In general, there was functional consistency among species in growth responses to light, foliar N, and Soil water availability, respectively. Foliar N influenced primarily high-light growth in F. grandifolia, A. rubrum, and Q. rubra (but was not significant for A. saccharum). In A. saccharum and A. rubrum, for which Soil water availability was a significant predictor, Soil water and light availability simultaneously limited growth (i.e., either higher light or water increased growth). Simple resource-based models explained 0.74-0.90 of growth variance, indicating a high degree of determinism. Results suggest that nitrogen effects on forest dynamics would be strongest in high-light early successional communities but that water availability influences growth in both early successional and understory environments.
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tree seedling growth survival and morphology in response to landscape level variation in Soil resource availability in northern michigan
Canadian Journal of Forest Research, 2005Co-Authors: Laura A Schreeg, Richard K Kobe, Michael B WaltersAbstract:To investigate causes of tree species distributions across Soil Resources in northern Michigan, we conducted a seedling transplant experiment with five species showing different site affinities: Ac...
