Shrub mound formation and stability on semi-arid slopes in the Northern Negev Desert of Israel: A field and simulation study
Buis, E. ; Temme, A.J.A.M. ; Veldkamp, A. ; Boeken, B. ; Jongmans, A.G. ; Breemen, N. van; Schoorl, J.M. - \ 2010
Geoderma 156 (2010)3-4. - ISSN 0016-7061 - p. 363 - 371.
biological soil crusts - southern arizona - arid ecosystems - vegetation patterns - hillslope erosion - water erosion - overland-flow - walnut-gulch - landscape - runoff
In semi-arid areas vegetation is scarce and often dominated by individual shrubs on raised mounds. The processes of formation of these mounds are diverse and still debated. Often, shrub mound formation is directly related to the formation of vegetation patterns, thereby assuming that shrub mound formation is driven by biological interactions. We hypothesize that water-related erosion and sedimentation are also important drivers of shrub mound formation in the Northern Negev Desert of Israel. We test this hypothesis by combining field observations with model simulations. We studied shrub mounds in the semi-arid catchment of Sayeret Shaked in the Northern Negev Desert (200 mm annual precipitation). Height and diameter of shrub-canopy and shrub mounds were measured and micro-morphological techniques were used to reconstruct the formation of the shrub mounds. We used landscape evolution model LAPSUS to simulate shrub mound formation at short (single precipitation event) and longer (100 years) timescales at different slope angles. Both field and model results indicate that shrub mounds in Sayeret Shaked are at least partly formed by redeposition of eroded material below the shrubs, and by erosion and lowering of the surrounding crust. Additional model simulations suggest that mounds are formed most under low shrub density and large shrub-canopy diameter. Shrub mound formation increases with slope. In dryer and wetter climates than the studied 200 mm rainfall semi-arid climate zone, shrub mound formation is less likely
Controls on plant functional surface cover types along a precipitation gradient in the Negev Desert of Israel
Buis, E. ; Veldkamp, A. ; Boeken, B. ; Breemen, N. van - \ 2009
Journal of Arid Environments 73 (2009)1. - ISSN 0140-1963 - p. 82 - 90.
biological soil crusts - arid ecosystems - water redistribution - spatial-distribution - asphodelus-aestivus - climatic gradient - rock fragments - vegetation - infiltration - resilience
We studied the controls on functional surface cover types in four catchments along a semi-arid to arid precipitation gradient in the northern Negev Desert of Israel. First, we selected four functional types, based on their unique water use and redistribution functionality: shrubs, Asphodelus ramosus, other herbaceous plants and surface crusts. We estimated percentage of surface covered by these functional types and by bedrock outcrops and loose surface stones. Additionally data was collected on soil depth, relative elevation, insolation, slope, curvature, and overlain with surface cover maps. Relations between functional types and landscape structure variables were analyzed with descriptive statistics. The landscape structure variables bedrock, relative elevation, soil depth and surface stones explained most of the cover variance in the catchments. In catchments with many bedrock outcrops, functional types were best explained by the landscape structure variables. In catchments with homogeneous soils reaching beyond the root zone, the biological interactions between functional types were more important. Along the precipitation gradient the explanatory power of the biological variables decreased with decreasing precipitation, while the explanatory power of landscape structure variables appeared unrelated. Only in homogeneous semi-arid catchments regular vegetation patterns can develop, in arid and heterogeneous catchments irregular patterns dominate.
Rock-eating mycorrhizas: their role in plant nutrition and biogeochemical cycles
Schöll, L. van; Kuyper, T.W. ; Smits, M.M. ; Landeweert, R. ; Hoffland, E. ; Breemen, N. van - \ 2008
Plant and Soil 303 (2008)1-2. - ISSN 0032-079X - p. 35 - 47.
fungus paxillus-involutus - norway-spruce seedlings - organic anion exudation - ectomycorrhizal fungi - pinus-sylvestris - forest soil - boreal forest - extramatrical mycelium - aluminum tolerance - carbon allocation
A decade ago, tunnels inside mineral grains were found that were likely formed by hyphae of ectomycorrhizal (EcM) fungi. This observation implied that EcM fungi can dissolve mineral grains. The observation raised several questions on the ecology of these ¿rock-eating¿ fungi. This review addresses the roles of these rock-eating EcM associations in plant nutrition, biogeochemical cycles and pedogenesis. Research approaches ranged from molecular to ecosystem level scales. Nutrient deficiencies change EcM seedling exudation patterns of organic anions and thus their potential to mobilise base cations from minerals. This response was fungal species-specific. Some EcM fungi accelerated mineral weathering. While mineral weathering could also increase the concentrations of phytotoxic aluminium in the soil solution, some EcM fungi increase Al tolerance through an enhanced exudation of oxalate. Through their contribution to Al transport, EcM hyphae could be agents in pedogenesis, especially podzolisation. A modelling study indicated that mineral tunnelling is less important than surface weathering by EcM fungi. With both processes taken together, the contribution of EcM fungi to weathering may be significant. In the field vertical niche differentiation of EcM fungi was shown for EcM root tips and extraradical mycelium. In the field EcM fungi and tunnel densities were correlated. Our results support a role of rock-eating EcM fungi in plant nutrition and biogeochemical cycles. EcM fungal species-specific differences indicate the need for further research with regard to this variation in functional traits.
Modelling landscape dynamics in the Northern Negev Desert of Israel using LAPSUS
Buis, E. ; Veldkamp, A. ; Boeken, B. ; Breemen, N. van - \ 2008
Shrub mound formation and their stability on semi-arid slopes: integrating field and simulation studies with the landscape evolution model LAPSUS
Buis, E. ; Veldkamp, A. ; Boeken, B. ; Jongmans, A.G. ; Schoorl, J.M. ; Breemen, N. van - \ 2008
|Modelling self organizing shrub mound formation and their stability on semi-arid slopes
Buis, E. ; Veldkamp, A. ; Schoorl, J.M. ; Boeken, B. ; Breemen, N. van - \ 2007
Element interactions limit soil carbon storage
Groenigen, K.J. van; Six, J. ; Hungate, B.A. ; Graaff, M.A. de; Breemen, N. van; Kessel, C. van - \ 2006
Proceedings of the National Academy of Sciences of the United States of America 103 (2006)17. - ISSN 0027-8424 - p. 6571 - 6574.
elevated atmospheric co2 - biological nitrogen-fixation - ecosystem responses - climate-change - fine roots - grassland - forest - model - cycles - metaanalysis
Rising levels of atmospheric CO2 are thought to increase C sinks in terrestrial ecosystems. The potential of these sinks to mitigate CO2 emissions, however, may be constrained by nutrients. By using metaanalysis, we found that elevated CO2 only causes accumulation of soil C when N is added at rates well above typical atmospheric N inputs. Similarly, elevated CO2 only enhances N-2 fixation, the major natural process providing soil N input, when other nutrients (e.g., phosphorus, molybdenum, and potassium) are added. Hence, soil C sequestration under elevated CO2 is constrained both directly by IN availability and indirectly by nutrients needed to support N2 fixation.
Controlling vegetation patterns in deserts. The story of the Negev
Buis, E. ; Veldkamp, A. ; Breemen, N. van; Boeken, B. - \ 2006
In: Book of Abstracts. Highland Symposium on environmental change, geomorphic processes, land degradation and rehabilitation in tropical and subtropical highlands, Mekelle, Ethiopia, 19-25 September 2006. - Leuven/Mekelle, Ethiopia : KU Leuven/Zemenawi Printing Mekelle - p. 17 - 17.
Upscaling regional emissions of greenhouse gases from rice cultivation: methods and sources of uncertainty
Verburg, P.H. ; Bodegom, P.M. van; Denier van der Gon, H.A.C. ; Bergsma, A. ; Breemen, N. van - \ 2006
Plant Ecology 182 (2006)1-2. - ISSN 1385-0237 - p. 89 - 106.
methane emissions - atmospheric methane - water management - ch4 emission - paddy soils - fields - model - china - variability - sensitivity
One of the important sources of greenhouse gases is the emission of methane from rice fields. Methane emission from rice fields is the result of a complex array of soil processes involving plant-microbe interactions. The cumulative effects of these processes at the level of individual plants influence the global atmospheric composition and make it necessary to expand our research focus from small plots to large landscapes and regions. However, present extrapolations (`upscaling¿) are tenuous at best because of methodological and practical problems. The different steps taken to calculate regional emission strengths are discussed and illustrated by calculations for a case-study in the Philippines. The applicability of high quality, process-based, models of methane emission at the level of individual plants is limited for regional analysis by their large data requirements. Simplified models can be used at the regional level but are not able to capture the complex emission situation. Data availability and model accuracy are therefore often difficult to match. Other common sources of uncertainty are the quality of input data. A critical evaluation of input data should be made in every upscaling study to assess the suitability for calculating regional emissions. For the case-study we show effects of differences in input data caused by data source and interpolation technique. The results from the case-study and similar studies in literature indicate that upscaling techniques are still troublesome and a cause of large uncertainties in regional estimates. The results suggest that some of the stumbling blocks in the conventional upscaling procedure are almost impassable in the near future. Based on these results, a plea is made for meso-level measurements to calibrate and validate upscaling methods in order to be better able to quantify and reduce uncertainties in regional emission estimates
Organic anion exudation by ectomycorrhizal fungi and Pinus sylvestris in response to nutrient deficiences
Schöll, L. van; Hoffland, E. ; Breemen, N. van - \ 2006
New Phytologist 170 (2006)1. - ISSN 0028-646X - p. 153 - 163.
in-vitro - paxillus-involutus - soil solution - forest soil - mg2+ deficiency - oxalic-acid - oxalate - roots - mycorrhizal - seedlings
Low molecular weight organic anions (LMWOA) can enhance weathering of mineral grains. We tested the hypothesis that ectomycorrhizal (EcM) fungi and tree seedlings increase their exudation of LMWOA when supply of magnesium, potassium and phosphorus is low to enhance the mobilization of Mg, K and P from mineral grains. ¿ Ectomycorrhizal fungi and Pinus sylvestris seedlings were cultured in symbiosis and in isolation on glass beads with nutrient solution or with sand as a rooting medium, with a complete nutrient supply or with Mg, K, P or N in low supply. Concentrations of all dicarboxylic LMWOA in the rooting medium were measured. ¿ Nonmycorrhizal seedlings released predominantly malonate. Colonization with Hebeloma longicaudum decreased the amount of organic anions exuded, whereas Paxillus involutus and Piloderma croceum increased the concentration of oxalate but not the total amount of LMWOA. Phosphorus deficiency increased the concentration of LMWOA by nonmycorrhizal and EcM seedlings. Magnesium deficiency increased the concentration of oxalate by nonmycorrhizal and EcM seedlings, but not the concentration of total LMWOA. Paxillus involutus grown in pure culture responded differently to low nutrient supply compared with symbiotic growth. ¿ Ectomycorrhizal fungi did not increase the total concentration of LMWOA compared with nonmycorrhizal seedlings but, depending on the fungal species, they affected the type of LMWOA found.
Soil organic matter distribution and microaggregate characteristics as affected by agricultural management and earthworm activity
Pulleman, M.M. ; Six, J. ; Breemen, N. van; Jongmans, A.G. - \ 2005
European Journal of Soil Science 56 (2005)4. - ISSN 1351-0754 - p. 453 - 467.
no-tillage agroecosystems - arable soil - carbon - casts - aggregation - dynamics - pasture - sequestration - oligochaeta - grassland
Stable microaggregates can physically protect occluded soil organic matter (SOM) against decomposition. We studied the effects of agricultural management on the amount and characteristics of microaggregates and on SOM distribution in a marine loam soil in the Netherlands. Three long-term farming systems were compared: a permanent pasture, a conventional-arable system and an organic-arable system. Whole soil samples were separated into microaggregates (53–250 µm), 20–53 µm and <20 µm organo-mineral fractions, sand and particulate organic matter, after complete disruption of macroaggregates. Equal amounts of microaggregates were isolated, irrespective of management. However, microaggregates from the pasture contained a larger fraction of total soil organic C and were more stable than microaggregates from the two arable fields, suggesting greater SOM stabilization in microaggregates under pasture. Moreover, differences in the relative contribution of coarse silt (> 20 µm) versus fine mineral particles in the microaggregates of the different management systems demonstrate that different types of microaggregates were isolated. These results, in combination with micromorphological study of thin sections, indicate that the great earthworm activity under permanent pasture is an important factor explaining the presence of very stable microaggregates that are relatively enriched in organic C and fine mineral particles. Despite a distinctly greater total SOM content and earthworm activity in the organic- versus the conventional-arable system, differences in microaggregate characteristics between both arable systems were small. The formation of stable and strongly organic C-enriched microaggregates seems much less effective under arable conditions than under pasture. This might be related to differences in earthworm species' composition, SOM characteristics and/or mechanical disturbance between pasture and arable land.
Effect of ectomycorrhizal fungi on the uptake of Ca, Mg and Al by Pinus sylvestris under aluminium toxicity
Schöll, L. van; Keltjens, W.G. ; Hoffland, E. ; Breemen, N. van - \ 2005
Forest Ecology and Management 215 (2005)1-3. - ISSN 0378-1127 - p. 352 - 360.
norway spruce seedlings - fungus suillus-variegatus - picea-abies seedlings - paxillus-involutus - mineral-nutrition - rigida seedlings - nutrient-uptake - critical loads - organic-acids - forest soils
Aluminium toxicity has been considered an important factor in forest decline. In earlier pot experiments, ectomycorrhizal tree seedlings were reported to have higher growth rates than non-mycorrhizal seedlings under aluminium toxicity. In this paper, we test that if this is caused by exclusion of Al and higher uptake of Ca and Mg by the ectomycorrhizal roots. Pinus sylvestris seedlings, grown for 3 months on a semi-hydroponic system, were continuously drip-irrigated with nutrient solution, containing 0 or 1.5 mM Al. The seedlings were non-mycorrhizal or colonized by ectomycorrhizal fungal species from a podzol soil. The presence of 1.5 mM Al in solution significantly decreased the dry weights of needles and roots compared to the control, and increased mycorrhizal colonization. Yet growth was not affected by mycorrhizal colonization. Concentrations of Al in the needles were significantly higher at 1.5 mM Al in solution than at 0 mM Al, and significantly higher in ectomycorrhizal seedlings than in non-mycorrhizal seedlings. Concentrations of Ca and Mg in the needles were significantly lower at 1.5 mM Al in solution than at 0 mM Al, but were not affected by ectomycorrhizal colonization. In conclusion, ectomycorrhizal colonization did not mitigate aluminium toxicity in our semi-hydroponic system. We suggest that better growth of soil-grown ectomycorrhizal tree seedlings compared to non-mycorrhizal tree seedlings should be explained by improved uptake of immobile nutrients such as P through a better soil exploration by the external mycelium or by detoxification of Al by organic anions excreted by the fungi
Contribution of mineral tunneling to total feldspar weathering
Smits, M.M. ; Hoffland, E. ; Jongmans, A.G. ; Breemen, N. van - \ 2005
Geoderma 125 (2005)1-2. - ISSN 0016-7061 - p. 59 - 69.
michigan sand dunes - lake-michigan - plant nutrition - hubbard brook - fungi - soils - potassium - biogeochemistry - chronosequence - calcium
In this study, we quantified the contribution of mineral tunneling by fungi to weathering of feldspars and ecosystem influx of K and Ca. We studied the surface soils of 11 podzols across a Lake Michigan sand dune chronosequence with soil ages between 450 and 5000 years. Weathering by tunneling was quantified in thin sections by image analysis. Total mineral weathering was quantified by comparing the mineralogy of the surface soil with the underlying parent material was characterized using X-ray fluorescence spectroscopy (XRFS), followed by a non-native mineralogical calculation. Tunnels were observed only in soils older than 1650 years. Throughout the chronosequence the contribution of tunneling to mineral weathering in the upper mineral soil, expressed as tunnel volume divided by volume of weathered feldspars was less then 1%. Contribution of tunneling to Na/Ca-feldspar weathering was higher than the contribution of tunneling to K-feldspar weathering. Feldspar tunneling equals an average ecosystem influx of 0.4 g ha(-1) year(-1) for K and 0.2 g ha(-1) year(-1) for Ca over 5000 years of soil development. Intensity of mineral tunneling, determined as fraction weathered feldspars, was higher than in a previously described North Swedish podzol chronosequence. The presented data suggest that the contribution of tunneling to weathering becomes more important in older soils, but remains low. (C) 2004 Elsevier B.V. All rights reserved.
|Role of ectomycorrhizal fungi in the uptake of Mg by Scots Pine (Pinus sylvestris)
Schöll, L. van; Hoffland, E. ; Keltjens, W.G. ; Breemen, N. van - \ 2005
In: Book of Abstracts of the International Congress Rhizosphere 2004 - Perspectives and challenges - A tribute to Lorenz Hiltner, Munich, Germany, 12 t/m 17 September 2004. - Munich : - p. 109 - 109.
|The formation of soils
Breemen, N. van - \ 2004
In: Vital Soil, function, value and properties / Doelman, P., Eijsackers, H.J.P., Elsevier (Developments in soil science 29) - ISBN 9780444517722 - p. 21 - 40.
bodemvorming - soil formation
Ik ga vandaag iets heel nieuws ontdekken en ik ben toch zo benieuwd wat dat zal zijn
Breemen, N. van - \ 2004
Wageningen : Laboratorium voor Bodemkunde en Geologie WU - 25
landbouwwetenschappen - innovaties - filosofie - bodemchemie - subsidies - wetenschappelijk onderzoek - financieren - openbare redes - soil chemistry - agricultural sciences - innovations - philosophy - scientific research - financing - public speeches
Aan de hand van eigen bodemkundige onderzoek. Het gaat om het verschijnsel 'serendipiteit': vinden van iets waar je niet naar op zoek wasservaringen betoogt de aftredend hoogleraar, dat het bedrijfsleven geen belangrijke rol kan spelen bij de financiering van echt vernieuwend wetenschappelijk onderzoek. Het gaat om het verschijnsel 'serendipiteit': vinden van iets waar je niet naar op zoek was
History and prospect of catchment biogeochemistry: a european perspective based on acid rain
Breemen, N. van; Wright, R.F. - \ 2004
Ecology 85 (2004)9. - ISSN 0012-9658 - p. 2363 - 2368.
verzuring - oppervlaktewater - zure regen - luchtverontreiniging - biogeochemie - monitoring - stroomgebieden - aquatisch milieu - acidification - surface water - acid rain - air pollution - biogeochemistry - monitoring - watersheds - aquatic environment - experimental lakes area - experimental acidification - ecosystem experiments - nitrogen saturation - ammonium-sulfate - soil-water - forest - deposition - project - budgets
Hydrochemical monitoring of catchments provided a philosophical framework as well as hard data to understand and quantify the linked biological and abiotic processes that explain how atmospheric deposition of S and N changed soils and waters in nonagricultural areas across Europe. Initially, as a tool to collect relevant data in a representative and systematic way, hydrochemical monitoring provided evidence for widespread surface water acidification related to atmospheric pollution and long-range air transport. Recognizing the strong effect biota can have on their chemical environment, in the context of catchment biogeochemistry, these data provided new insights into individual processes of soil and water acidification and helped to quantify the relative importance of natural and anthropogenic sources of H+. Furthermore, combined with large-scale ecosystem manipulation and modeling, catchment biogeochemistry offered an effective tool to investigate risks of acidification and of nitrogen saturation of soils and waters
|Wat, waar, waarom? Landschap en bodemgebruik rondom Wageningen
Baren, H. van; Breemen, N. van; Jongmans, T. ; Rogaar, H. ; Vervloet, J.A.J. - \ 2004
Wageningen : Museum De Casteelse Poort - 32 p.
|Contribution of ectomycorrhizal fungi to plant uptake of Ca, Mg and K and to mineral weathering
Tunneling, L. ; Schöll, L. van; Smits, M.M. ; Hoffland, E. ; Keltjens, W.G. ; Jongmans, A.G. ; Breemen, N. van - \ 2004
In: Book of Abstracts, Fourth International Conference on Mycorrhizas, Montreal, 10-15 August 2003. - Montreal : - p. 338 - 338.
Aluminium concentration versus the base cation to aluminium ratio as predictors for aluminium toxicity in Pinus sylvestris and Picea abies seedlings
Schöll, L. van; Keltjens, W.G. ; Hoffland, E. ; Breemen, N. van - \ 2004
Forest Ecology and Management 195 (2004)3. - ISSN 0378-1127 - p. 301 - 309.
norway spruce seedlings - gleditsia-triacanthos l - critical loads - root-growth - forest soils - calcium - magnesium - plants - inhibition - resistance
Aluminium (Al) toxicity is considered an important factor in forest deterioration caused by soil acidification. A ratio of base cations (BC) to Al in the soil solution lower than 1 is widely used as an indicator for potentially adverse effects on tree health. In our view, the validity of the assumptions underlying the use of the BC:AI ratio as an indicator for Al toxicity in trees has never been evaluated properly. Here, we evaluate the importance of the base cations Ca and Mg in counteracting Al toxicity. Pinus sylvestris and Picea abies seedlings were grown on nutrient solution with a range of Al (0-0.25-0.5-1-2 mM) and base cation (0.25-0.5-2 mM) concentrations, giving BC:Al ratios of 1 at different levels of Al. Increasing concentrations of Al in solution caused growth reductions, which could not be counteracted by increasing concentrations of BC in solution with P. sylvestris and only partly counteracted with P. abies. Increased concentrations of Al in solution decreased the concentrations in shoot and root of both Ca and Mg, while increased concentrations of BC in solution increased tissue concentrations of BC. Growth reductions were, however, not a result of BC deficiencies, as growth reduction already occurred in tree seedlings that maintained adequate concentrations of Ca and Mg. All growth and uptake variables measured showed a higher or equal correlation with the absolute concentrations of Al or Al + BC in solution than with the BC:Al ratio. We conclude that Al toxicity is determined solely by the concentration of Al in solution. Shoot growth decreased significantly as dissolved Al increased at a constant BC:Al ratio of 1. In P. abies, but not in P. sylvestris, dissolved BC can positively affect uptake of BC and growth, which might partly alleviate the toxic effects of Al. Our results show that the mechanistic explanation for the effect of the BC:Al ratio is insufficient to describe Al toxicity. Care should be taken when using models based on the BC:AI ratio to predict the effect of Al on tree growth. (C) 2004 Elsevier B.V. All rights reserved.