Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Geochemische schematisering van de ondergrond in het STONE model : schatting van het ammonium oxalaat extraheerbare aluminium- en ijzergehalte
    Boekel, E.M.P.M. - \ 2009
    Wageningen : Alterra (Alterra-rapport 1831) - 77
    geochemie - bodemchemie - aluminium - oxalaten - ijzer - humus - meting - fosfaatuitspoeling - geochemistry - soil chemistry - aluminium - oxalates - iron - humus - measurement - phosphate leaching
    De aluminium- en ijzeroxalaat gehalten spelen een belangrijke rol bij het voorspellen van de fosforverliezen naar het oppervlaktewater. Het nauwkeurig schatten van deze gehalten in de ondergrond is noodzakelijk om op de lange termijn effecten goed te kunnen kwantificeren. Met behulp van Landelijke Steekproef Kaarteenheden en het Bodemkundig Informatiesysteem zijn per grondsoort en geologische afzettingen regressievergelijkingen opgesteld voor het schatten van het (Al+Fe)ox gehalte op basis van het lutum en/of humusgehalten. Vervolgens zijn de (Al+Fe)ox gehalten voor de ondergrond van de STONE-plots opnieuw geschat. De geschatte (Al+Fe)ox gehalten voor de nieuwe STONE-schematisering zijn significant lager dan de (Al+Fe)ox gehalten in de huidige schematisering, waardoor het fosfaatbindend vermogen lager wordt. Dit heeft vervolgens effect op de fosforbelasting naar grond- en oppervlaktewater op de lange termijn.
    Proton buffering and metal mobility in Dutch sandy soils : modeling laboratory and field data
    Fest, P.M.J. - \ 2007
    Wageningen University. Promotor(en): Willem van Riemsdijk, co-promotor(en): Erwin Temminghoff. - [S.l.] : S.n. - ISBN 9789085046899 - 215
    zandgronden - bodemchemie - bodemeigenschappen - zware metalen - buffercapaciteit - organisch bodemmateriaal - humuszuren - fulvozuren - aluminium - grondwaterverontreiniging - uitspoelen - sandy soils - soil chemistry - soil properties - heavy metals - buffering capacity - soil organic matter - humic acids - fulvic acids - aluminium - groundwater pollution - leaching
    Momenteel wordt steeds meer landbouwgrond uit productie genomen en veranderd in natuurgebieden. Tijdens deze omzetting kunnen veranderingen optreden in bodemeigenschappen. Veel landbouwgronden hebben verhoogde gehalten aan zware metalen. Dit proefschrift laat de toepassing zien van geochemische modellen bij het voorspellen van het gedrag van zware metalen in zandige bodems. Deze voorspellingen kunnen in de praktijk worden toegepast bij milieuonderzoeken en beleidsplannen. De geochemische modelberekeningen zijn toe te passen zowel op landbodems als waterbodems
    Ectomycorrhizal fungi and Pinus sylvestris: aluminium toxicity, base cation deficiencies and exudation of organic anions.
    Schöll, L. van - \ 2006
    Wageningen University. Promotor(en): N. van Breemen, co-promotor(en): Ellis Hoffland. - Wageningen : - ISBN 9789085043966 - 156
    pinus sylvestris - paxillus involutus - ectomycorrhiza - aluminium - toxiciteit - bodemschimmels - kationen - organische anionen - oxalaten - pinus sylvestris - paxillus involutus - ectomycorrhizas - aluminium - toxicity - soil fungi - cations - organic anions - oxalates
    Keywords: aluminium (Al), base cations, BC:Alratio, magnesium (Mg), organic anions, oxalate, malonate, ectomycorrhizal fungi, Paxillus involutus, Pinus sylvestris (Scots pine)

    The finding of microscopic-small tunnels in mineral grains in podzol soils was the incentive for a research programme on rock-eating mycorrhizae. The research described in this thesis was part of that program. The tunnels were thought to be created by ectomycorrhizal (EcM) fungi through exudation of low molecular weight organic anions (LMWOA). LMWOA can detoxify Al by forming stabile non-toxic complexes and can enhance mineral weathering, thereby mobilising base cations for plant and fungus. In this study we demonstrated that a role for EcM-fungi in detoxification of Al and in mobilisation of base cations from mineral grains is likely since both toxic Al levels and low base cation supply induced LMWOA exudation by ectomycorrhizae.

    The risk for Al toxicity is often assessed by regarding the ratio of base cations (BC) to Al in the soil solution. Adverse effects on tree growth are expected at BC:Al<1. We demonstrated that Al toxicity is not determined by the BC:Alratio. Growth reductions in Pinus sylvestris and Picea abies seedlings were better predicted by the concentration of BC and Al in solution than by the BC:Alratio. At a constant BC:Al ratio of 1, shoot growth decreased with increasing concentrations of Al. Seedlings of P. sylvestris responded to Al by the exudation of LMWOA. Indeed, EcM fungi enhanced this exudation, suggesting a role for EcM-exuded LMWOA in detoxifying Al. The exudation was further enhanced when levels of toxic Al were combined with deficient Mg and P supply. EcM fungi did not physically hinder Al uptake and did not improve uptake of Ca or Mg under Al toxicity.

    Ectomycorrhizae affected the exudation of LMWOA and weathering of minerals when plants were deficient in Mg, K or P. The exudation of LMWOA (mainly oxalate and malonate) was nutrient-specific and EcM species-specific. Exudation of LMWOA by the EcM symbiosis could not be predicted from the exudation of LMWOA by seedlings or EcM fungi grown in pure culture. The oxalate exudation by ectomycorrhizae in response to Mg and K deficiencies correlated well with the ectomycorrhizal induced weathering of minerals containing K and Mg .Weathering of the K-containing muscovite was almost doubled if seedlings were colonised by P. involutus compared to seedlings colonised by other EcM fungi or without mycorrhizae. There was no effect of EcM fungi on the weathering of Mg-containing hornblende. Localised Mg addition stimulated EcM foraging under Mg deficiency. Hyphal foraging and transport of Mg to the roots was independent of P supply or P transport.
    Ectomycorrhizal Fungi and Biogeochemical Cycles of Boreal Forests
    Smits, M.M. - \ 2006
    Wageningen University. Promotor(en): N. van Breemen, co-promotor(en): Ellis Hoffland. - Wageningen : s.n. - ISBN 9789085042907 - 122
    ectomycorrhiza - schimmels - boreale bossen - biogeochemie - aluminium - podzolisatie - verwering - podzolen - ectomycorrhizas - fungi - boreal forests - biogeochemistry - aluminium - podzolization - weathering - podzols
    Inpodzolsin Europe and North America tunnels in weatherable mineral grains were found, presumably created by ectomycorrhizal (EcM) fungi. This finding was the incentive for a research program on rock-eating mycorrhizas, of which this project is part of. The focus of this thesis is on the role of EcM fungi in mineral weathering and upward transport of aluminium in podzols of boreal forests. I studied fungal tunnelling in a soil chronosequence in Michigan because mineral weathering is a slow process. Tunnelling accounted for less than 0.5% of total feldspar weathering over 5000 yr of soil formation. Tunnelling is only one part of EcM weathering; processes on the surface were hypothesised to be more important. To study EcM weathering on the mineral surface I modelled the effect of oxalate exudation by EcM on feldspar weathering. The model estimated that the maximum contribution of oxalate produced by EcM fungi to total weathering is 14.5% for K-feldspar and 13.1% for Na/Ca-feldspar. Furthermore I did a pot experiment with Scots pine seedlings and three different EcM fungi and muscovite as only K-source or hornblende as only Mg-source. Only Paxillus involutus enhanced muscovite weathering compared to the non-mycorrhizal control. None of the EcM fungi increased hornblende weathering. The second part of the research was about upward aluminium transport in podzols. Budgets studies indicate a considerable unexplained upward transport of Al from the mineral horizons to the organic top layer. A possible mechanism could be transport through EcM hyphae, attached to root tips in the organic soil layer, and extending into the mineral soil. An in vitro test showed transport of Al by two of the five fungal isolates tested. Subsequently, tree seedlings were grown in an artificial podzol. I used gallium as a proxy for Al transport. A previous in vitro test with P. involutus and Suillus bovinus confirmed the use of Ga as proxy for Al. Gallium was transported from the mineral soil to the organic soil, also if onlyEcMfungi had access to it. This suggests a role forEcMfungi in upward Ga and, possibly, Al transport.
    Citrate exudation by maize roots; A possible mechanism of resistance to aluminium
    Mariano, E.D. - \ 2003
    Wageningen University. Promotor(en): Willem van Riemsdijk, co-promotor(en): W.G. Keltjens. - [S.l.] : S.n. - ISBN 9789058088925 - 128
    zea mays - maïs - citraten - aluminium - wortels - exudatie - bodemgiftigheid - plantenontwikkeling - genetische variatie - voedingsstoffenopname (planten) - zea mays - maize - citrates - aluminium - roots - exudation - soil toxicity - plant development - genetic variation - nutrient uptake

    Low-molecular-weight organic anions have been intensively studied as possibly involved in a mechanism of Al resistance in plants, due to their involvement in many metabolic processes and to their negative charge, conferring them the capacity to complex metals. The objective of the thesis was to study the root exudation of organic anions as a potential mechanism of Al resistance operating in maize ( Zea mays L.). The effect of Al exposure on root organic anion exudation was studied with roots grown under sterile conditions, with maize genotypes that differ in sensitivity to Al. Citrate accounted for the majority of the organic anions exuded, followed by malate, trans -aconitate, fumarate, and cis -aconitate. Along the longitudinal axis of fully developed seminal roots citrate was exuded mainly in the regions of root apices, either belonging to the main root or to the lateral roots in the most basal part of the main root. Rates of citrate exudation from root apices of eight genotypes exposed to Al correlated significantly well with their relative Al resistance; a less inhibited root elongation accompanied higher exudation rates.

    The effects of Al on nutrient uptake were also studied in the thesis. The spatial localisation of nutrient uptake on the root axis of maize seedlings was assessed and revealed that Al is affecting nutrient uptake widely along the longitudinal axis of the root. Compared with the pattern of citrate exudation along similar axes it seems that citrate is probably primarily involved in making plants resistant to Al by detoxifying Al around the root meristems, the most sensitive part for root growth. Local citrate exudation does not seem to be directly involved in nutrient uptake, because the segment with the highest citrate exudation (the apex) shows almost no nutrient uptake, while the root zone with the highest nutrient uptake shows almost zero citrate exudation.

    The question whether quantitatively the amounts of these small ligands released in the root environment are adequate to explain resistance to Al was tackled by combining experimental and modelling work. The results of the simulations strongly support the notion that citrate indeed can underlie Al resistance in maize. For the conditions considered in this study, detoxification of apoplastic Al and protection of this compartment seem more realistic and more important than those in the interface root-outer solution.

    Al toxicity and plant nutrient uptake: a role for root cell walls, pH and organic chelators
    Postma, J. - \ 2003
    Wageningen University. Promotor(en): Willem van Riemsdijk, co-promotor(en): W.G. Keltjens. - Wageningen : S.n. - ISBN 9789058089298 - 169
    planten - aluminium - voedingsstoffenopname (planten) - plantenvoeding - fytotoxiciteit - wortels - celwanden - chelaatvormers - plants - aluminium - nutrient uptake - plant nutrition - phytotoxicity - roots - cell walls - chelating agents
    Aluminium speciation in natural waters: measurement using Donnan membrane technique and modeling using NICA-Donnan
    Weng, L.P. ; Temminghoff, E.J.M. ; Riemsdijk, W.H. van - \ 2002
    Water Research 36 (2002)17. - ISSN 0043-1354 - p. 4215 - 4226.
    metaalionen - aluminium - modellen - bodemoplossing - membranen - chemische speciatie - adsorptie - grondanalyse - bodemwater - metal ions - aluminium - models - soil solution - membranes - chemical speciation - adsorption - soil analysis - soil water - dissolved organic-matter - contaminated sandy soil - metal-ion binding - humic substances - ph - complexation - copper - solubility - protons - field
    The study of Al speciation is of interest for the assessment of soil and water quality. For the measurement of "free" aluminum (Al3+), a recently developed Donnan membrane technique was tested by measuring Al3+ in aluminum-fluoride solutions and gibbsite suspensions. It shows that the Donnan membrane technique can measure free Al3+ reliably up to 10¿9 M and the equilibration takes 3¿4 days. Next, Al binding to humic acid (HA) purified from a forest soil was measured using either the Donnan membrane technique or gibbsite suspension. Results were compared with those predicted with the non-ideal consistent competitive adsorption (NICA)-Donnan model. The predictions using the generic parameters without fitting were in reasonable agreement with the measured data. Finally, the Donnan membrane technique was used to determine Al binding to dissolved organic matter (DOM) in the solutions of 24 soil samples at pH interval of 3¿7. Measurements agree well with the predictions using the NICA-Donnan model assuming 30% of DOM is HA and 30% is fulvic acid. With this model, the effects of pH and DOM changes on the concentration of Al in 81 soil solutions were predicted reasonably without adjustment of model parameters. The comparison between the results of analysis and the modeling provides a mutual validation for the two methods
    Aluminum-contaminant transport by surface runoff and bypass flow from an acid sulphate soil
    Minh, L.Q. ; Tuong, T.P. ; Mensvoort, M.E.F. van; Bouma, J. - \ 2002
    Agricultural Water Management 56 (2002). - ISSN 0378-3774 - p. 179 - 191.
    kattekleigronden - bodemchemie - uitspoelen - aluminium - vietnam - acid sulfate soils - soil chemistry - leaching - aluminium - vietnam
    Quantifying the process and the amount of acid-contaminant released to the surroundings is important in assessing the environmental hazards associated with reclaiming acid sulphate soils (ASS). The roles of surface runoff and bypass flow (i.e. the rapid downward flow of free water along macropores through an unsaturated soil matrix) in transporting aluminum from three types of raised beds (soil ridges formed by piling up soil materials excavated from adjacent ditches) were studied in a Typic Sulfaquept in Can Tho, Vietnam. During the month of April, 1 h cumulative infiltration of the low raised beds (made only of the topsoil materials) and high raised beds (made of topsoil and jarositic layers) was significantly higher than that of the traditional raised beds (made of topsoil, jarositic and pyritic materials). As the rainfall season progressed, infiltration in July decreased four to seven-fold from the initial values in April, resulting in an increase in runoff. Due to surface crusting, the traditional raised beds yielded the highest runoff (110 versus 50–60 mm in the other types in July). Aluminum concentrations in the bypass flow (6–22 mmol l-1) associated with each of the three bed types were higher than in the runoff (3–14 mmol l-1). In low and high raised beds, the amounts of aluminum transported by bypass flow (15–16 kmol ha-1) was higher than in the runoff (4–6.5 kmol ha-1), while in the traditional type, the two components were similar (11–12 kmol ha-1). The total amount of aluminum released from the low raised beds was lowest. Low raised beds thus pose less environmental hazards to the surroundings compared to the other two types. Interventions that affect the amount of aluminum transport in runoff and in bypass flow are important in balancing agricultural production and environmental protection in ASS areas
    Relatie tussen vegetatie en abiotische factoren in het meetnet vitaliteit en verdroging; een statistische studie op grond van waarnemingen in 200 opstanden in 1995 en 1996
    Dobben, H.F. van; Vries, W. de - \ 2001
    Wageningen : Alterra (Alterra-rapport 406) - 53
    bossen - bodemchemie - milieufactoren - vegetatie - verdroging - stikstof - fosfor - fosfaten - aluminium - depositie - nederland - atmosferische depositie - biodiversiteit - bos - ecologie - nutriënten - forests - soil chemistry - environmental factors - vegetation - desiccation - nitrogen - phosphorus - phosphates - aluminium - deposition - netherlands - monitoring
    In de 200 bosopstanden van het meetnet vitaliteit en verdroging zijn in 1995 bodemchemische factoren bepaald en in 1996 vegetatieopnamen gemaakt. Deze gegevens zijn gebruikt om de relatie vast te stellen tussen bodem en vegetatie. Additioneel zijn niet-bodemchemische variabelen gebruikt, die deels afkomstig zijn uit landelijke gegevensbestanden en modellen (meteo, depositie). Er blijkt een sterke relatie te bestaan tussen de vegetatie en deze verklarende variabelen. De factoren die de vegetatie het meest bepalen, zijn licht, bodemchemie (vooral beschikbaarheid van basische kationen), atmosferische depositie, en grondwaterstand. Van de atmosferische variabelen hebben de depositie van Mg en van SOx een significant effect. De indicatoren voor stikstofdepositie (NOx en NHy) hebben geen significant effect op de vegetatie. Van de nutriënten in de bodem heeft fosfaat een groter effect dan stikstof, hetgeen wijst op stikstofverzadiging. Voorts werden aanwijzingen gevonden voor een toxisch effect van aluminium.
    Release rates of Al from inorganic and organic compounds in a sandy podzol, during laboratory experiments
    Salm, C. van der; Westerveld, J.W. ; Verstraten, J.M. - \ 2000
    Geoderma 96 (2000)3. - ISSN 0016-7061 - p. 173 - 198.
    bodemoplossing - bodem - aluminium - zure gronden - adsorptie - soil solution - soil - aluminium - acid soils - adsorption
    Research with respect to release rates of Al and Al concentrations in the soil solution has led to two contrasting hypotheses, stressing either the importance of kinetically constrained dissolution reactions or the role of complexation of Al to soil organic matter. The existence of two contrasting hypotheses is partly due to the fact that the interpretation of existing results is hampered by the lack of specificity of the extractants used to quantify the organic and inorganic pools of Al and by the fact that simultaneous measurements on the release of Al and the change in Al pools are missing. This study was conducted to obtain more information on the release rates of Al from various amorphous pools and to evaluate the validity of the above hypotheses. To overcome the above-mentioned shortcomings both release rates of Al and changes in the various,Al pools were measured during the experiment. Experiments were conducted for Ap, Bs and C horizons from a sandy podzol. Results indicated that Al was released from both the inorganic Al pool (oxalate minus pyrophosphate extractable Al) and the strongly bound organic Al pool (pyrophosphate minus CuCl2 extractable Al) according to a first-order reaction. The decline in the weakly bound organic Al pool (CuCl2 extractable minus adsorbed Al) could be described by a rapid dissolution of part of the pool, combined with an equilibrium reaction describing the complexation of Al to organic sites. Rate constants were highest for the non-complexed part of the weakly bound organic Al pool, intermediate for the inorganic Al pool and lowest for the strongly bound organic Al pool. Large differences exist in rate constants of the organic pools between the three horizons. Differences between the rate constants of the inorganic Al pool for the three horizons were not significant.
    Verkenning van de effecten van pH en organische zuren op de beschikbaarheid van aluminium rond wortels. I. Gedrag van enkele substraten zonder planten
    Visser, A.J.C. de - \ 1998
    Wageningen : AB-DLO
    plantenvoeding - aluminium - ph - rizosfeer - plant nutrition - aluminium - ph - rhizosphere
    Contamination of surface water as affected by land use in acid sulfate soils in the Mekong River Delta, Vietnam.
    Minh, L.Q. ; Tuong, T.P. ; Mensvoort, M.E.F. van; Bouma, J. - \ 1997
    Agriculture, Ecosystems and Environment 61 (1997). - ISSN 0167-8809 - p. 19 - 27.
    zure gronden - kattekleigronden - bodem - uitspoelen - aluminium - rivieren - waterlopen - kanalen - water - oppervlaktewater - waterverontreiniging - waterkwaliteit - Vietnam - acid soils - acid sulfate soils - soil - leaching - aluminium - rivers - streams - canals - water - surface water - water pollution - water quality - Vietnam
    Integrated soil and water management in acid sulphate soils : balancing agricultural production and environmental requirements in the Mekong Delta, Viet Nam
    Le, Q.M. - \ 1996
    Agricultural University. Promotor(en): J. Bouma, co-promotor(en): T.P. Tuong. - S.l. : Le Quang Minh - ISBN 9789054855569 - 134
    zure gronden - kattekleigronden - grondwaterspiegel - bodem - uitspoelen - aluminium - acid soils - acid sulfate soils - water table - soil - leaching - aluminium

    The objectives of this study in the Mekong delta, Vietnam, were: (1) to obtain a better understanding of the effects of soil physical properties and flow types on solute transport in ASS emphasing aluminum; (2) to quantify environmental hazards resulting from amelioration activities in acid sulphate soils (ASS); and (3) to identify measures which can increase agricultural production and reduce negative environmental side effects.

    This study was conducted on ASS in the Mekong delta, Vietnam and consisted of 5 experiments starting in the dry season and ending at the end of the flood season. All experiments were carried out under field conditions. Transport of soluble aluminum was investigated for different types of water flow, which are typical for each season such as capillary rise, bypass flow and runoff.

    During the dry season, soluble aluminum was accumulated in topsoil layers by capillary rise. Effects of land management methods on accumulation of aluminum was the main focus in this period: Plowing (P1) and mulching (Ml), compared with non-plowing (P0) and non-mulching (M0). Experiments were conducted in lysimeters, and under field conditions. In both experiments, topsoils were treated with P1M1, P1M0, P0M1, and P0M0. Three levels of ground water (GWL: 30, 60, and 90 cm below the ground surface) were maintained in the undisturbed soil columns in the lysimeters. Aluminum accumulation increased with increased evaporation. Under field conditions, where ground water levels were monitored but not controlled, mulching treatments gave a significantly lower aluminum accumulation as compared with the non-mulching treatments, whereas plowing did not result in a significant decrease of this accumulation. Rainfall during the first 3 weeks of the rainy season caused the ground water to rise rapidly while its aluminum concentration increased. This increased the soluble aluminum concentrations in the topsoils and eliminated the leaching effects of earlier land management practices.

    During the rainy season, the study was focused on aluminum transport with bypass flow and runoff in and on raised beds, which are constructed by soil materials excavated from adjacent lateral ditches with the objective to avoid flooding and to enhance leaching of soil. This is a very common technique to grow upland crops in ASS. Therefore, a better understanding of leaching processes in raised beds is needed to properly assess management options for ASS. Three types of raised beds, which are commonly constructed in the Mekong delta, were studied. In the low raised beds only topsoil material was used to construct the bed. In the high type both top soil and the jarosite layer were used. In the "traditional" raised beds, pyritic material was also found on top of the beds. The amount of runoff increased with cumulative rainfall due to a decrease of infiltration rates and saturated hydraulic conductivities. Due to surface crusting, traditional beds gave the highest runoff amounts among the three types. Concentrations of aluminum in bypass flow were consistently higher than in runoff In low and high beds, amounts of aluminum in bypass flow were also higher than in runoff, whereas in traditional bed-types it was slightly lower. However, the negative impacts on the surrounding surface water was not significantly different for the three types of beds. Therefore, the low bed type is the most desirable from an agricultural production point of view, because less effort is needed in construction.

    Pore system distribution can play a very important role in determining water flows in and on the raised beds and as a consequence, on the effectiveness of leaching toxic substances. Thus, field and laboratory studies were carried out to quantify the effects of soil physical properties and bypass flow on leaching processes of new, 1-year old and 2-year old raised beds for yam and pineapple cultivation. Water-conducting pores were characterized using Methylene Blue. Number, area, and perimeter of water- conducting pores at 10-cm depth intervals of six 1 x 1m subplots were investigated. Undisturbed 20 cm x 25 cm soil cores were subjected to three 30 mm h -1rains in 30 minutes. Volume, aluminum and sulphate concentration of outflows were monitored. Due to consolidation, the area and perimeter of water-conducting pores in 2-year old pineapple beds had decreased to about one third, and bypass flow rates to about 80% of those in newly constructed beds. Consolidation, however, did not affect macropore network geometry in yam beds because they were subjected to annual tillage and yam tubers were uprooted regularly. Al and SO42-concentrations in the outflows of newly constructed and 1-year old raised beds were higher in pineapple, while those in 2-year raised beds were higher in yam.

    A side effect of leaching of ASS may be the pollution of surrounding waters. In order to obtain a proper assessment of this problem, the concentration and the amount of aluminum in water leaching from ASS during cultivation of rice, pineapple and yam were investigated. The fields have been reclaimed for 2 months, 1 and 2 years, respectively. Pineapple and yam were cultivated on raised beds. Values of pH in drainage water ranged from 2.9 to 3.9 and aluminum concentration from 3 to 13 mmol(+) l -1. Mean monthly aluminum concentrations in the water discharged from pineapple and yam raised beds was about 3 times higher than from rice fields. Monthly total amount of aluminum released by the raised beds could be as high as 16,690 mol ha -1, and was 3 to 5 times higher than that from rice fields. Consolidation and crust formation in pineapple beds reduced the concentration and amount of aluminum released as the beds grew older. In June, leaching from ASS was most hazardous to the environment due to a combination of highest total aluminum released to the canal network and a relatively low river discharge.

    At the flood recession period, the effectiveness of flood water (in combination with harrowing) in flushing out toxic substances from the top soil of ASS was investigated. Three experimental sites with slight, moderate and strong acidity were selected. Treatments were the number of harrowings (one: H1 and three times: H3) and the number of flushings (one: F1 and three times: F3).Three times harrowing in combination with three times flushing was the most effective in leaching acid in the most acid soils. When flushing once, the number of harrowings had no effect. The quantity of aluminum adsorbed on the soil exchange complex was not affected by different harrowing and flushing treatments. F3H3 also gave a significantly higher rice yield as compared with other treatments. The flood recession period is the most appropriate moment for flushing topsoils for rice cultivation, which has a high water requirement.

    Impacts of acid deposition on concentrations and fluxes of solutes in acid sandy forest soils in the Netherlands.
    Vries, W. de; Grinsven, J.J.M. van; Breemen, N. van; Leeters, E.E.J.M. ; Jansen, P.C. - \ 1995
    Geoderma 67 (1995)1. - ISSN 0016-7061 - p. 17 - 43.
    neerslag - chemische eigenschappen - zuurgraad - zure regen - bodem - stikstof - zwavel - aluminium - bodem pH - bodemaciditeit - Nederland - precipitation - chemical properties - acidity - acid rain - soil - nitrogen - sulfur - aluminium - soil pH - soil acidity - Netherlands
    This article summarizes the most important impacts of acid atmospheric deposition on the soil solution chemistry of acid sandy forest soils in the Netherlands, by comparing and interpreting data from soil solution monitoring studies (18 stands) and a national soil solution survey (150 stands). Important conclusions are: forest soils are invariably saturated with sulphate (leaching equals deposition); there is generally a relatively large retention of nitrogen, although there are indications that forest soils become nitrogen-saturated at total inputs above 4.0 kmolc per ha per year aluminium mobilization is the major buffer mechanism neutralizing the acidity input.
    The solubility of aluminum in acidic forest soils: long-term changes due to acid deposition.
    Mulder, J. ; Stein, A. - \ 1994
    Geochimica et Cosmochimica Acta 58 (1994). - ISSN 0016-7037 - p. 85 - 94.
    bodem - aluminium - bruine bosgronden - neerslag - chemische eigenschappen - zuurgraad - zure regen - uitspoelen - soil - aluminium - brown forest soils - precipitation - chemical properties - acidity - acid rain - leaching
    Analysis of aluminium sensitivity in sorghum (Sorghum bicolor (L.) Moench) genotypes
    Tan, K. - \ 1993
    Agricultural University. Promotor(en): G.R. Findenegg; W.G. Keltjens. - S.l. : Tan - ISBN 9789054850946 - 155
    oogstschade - bodemverontreiniging - bodemgiftigheid - bodemzoutgehalte - Sorghum bicolor - toxische stoffen - chemie - indicatorplanten - toxinen - planten - bodem - aluminium - oogsttoename - oogstverliezen - opbrengsten - zure gronden - kattekleigronden - chemische factoren - crop damage - soil pollution - soil toxicity - soil salinity - Sorghum bicolor - toxic substances - chemistry - indicator plants - toxins - plants - soil - aluminium - yield increases - yield losses - yields - acid soils - acid sulfate soils - chemical factors

    Twelve genotypes of sorghum ( Sorghum bicolor (L.) Moench) differing in Al sensitivity were grown in an acid soil (with additions of lime or MgSO 4 ) and in nutrient solutions (with or without Al at constant pH) for periods between 14 and 35 days. The objective was the identification of the factors controlling dry matter yield of sorghum under different growth conditions. In both media Al was the major constraint, restricting growth in two independent ways: (1) by inducing Mg deficiency and (2) via damaging the roots ( i.e. by giving them a stubby and discolorated appearance and by reducing their specific root length, m g -1dry root). The sensitivities of the genotypes against Al-induced Mg deficiency and Al-induced root damage were not correlated. At moderate acidity (pH around 4.8), Mg deficiency dominantly limited growth whilst at a higher acidity (pH ~4.2) root damage overruled Mg deficiency in its negative effect on growth. At pH 4.8, addition of Mg improved growth by reducing the degree of Mg deficiency. At pH 4.2, Mg improved growth mainly by preventing the roots from Al- induced damage.

    Several external factors modified the AI sensitivity of the genotypes by strengthening or weakening the negative effects of Al on Mg nutrition and root development. At pH 4.2, Ca and NH 4 both counteracted AI-induced root damage but aggravated Al-induced Mg deficiency. The contrary was true for NO 3 . When the concentration of soluble Al was kept approximately constant at 15 μM, both Al-induced root damage and Mg deficiency were aggravated by acidity in the range pH 3.9-4.8. Aluminium toxicity in sorghum grown in nutrient solution was independent of P deficiency, although an increased P supply partly eliminated Al phytotoxicity.

    The results stress the importance of both Al and Mg ions and their interactions in determining growth response of sorghum and other cereals to acid soils.

    Aluminium avoidance by Mucuna pruriens
    Hairiah, K. ; Noordwijk, M. van; Stulen, I. ; Kuiper, P.J.C. - \ 1992
    Physiologia Plantarum 86 (1992). - ISSN 0031-9317 - p. 17 - 24.
    aluminium - oogstschade - Mucuna - plantenontwikkeling - plantenfysiologie - wortels - bodem - bodemverontreiniging - bodemzoutgehalte - bodemgiftigheid - aluminium - crop damage - Mucuna - plant development - plant physiology - roots - soil - soil pollution - soil salinity - soil toxicity
    The hypothesis was tested that the avoidance of acid subsoil by the velvet bean Mucuna pruriens is based on a mechanism acting on the whole root system rather than on individual roots. In a split-root experiment with circulating nutrient solution the growth of plants with Al-containing (+/+) or Al-free (0/0) solution on both sides of the root system was compared with that of plants which had a choice (0/+). Two levels of Al (110 and 185 μM) were tested at two levels of Ca (50 and 1250 μM). In the 185 μM Al treatment the concentration of monomeric Al varied between 53 μM, directly after refreshing the solution, and 5 μM at harvest time. An external Al concentration of 110 μM had no effect on shoot and root dry weight, while 185 μM Al applied to both sides of the root system (+/+) increased root dry weight and reduced shoot dry weight and shoot/root ratio, compared with the 0/0 control. Application of 185 μM Al to half of the roots, ied to a significant shift in root growth in favour of the control side; this response is described here as Al avoidance. On the basis of total root length, root dry weight and root surface area, the ratio of 0/+ roots was 3.1, 2.8 and 2.4, respectively. Al avoidance at 185 μM Al was confirmed in another experiment, in which root response was measured to a local P source, supplied in a third compartment containing only KH2PO4. A significant increase in root length and dry weight in this compartment was observed, when other roots of the same plant were growing in the presence of Al. This result indicates that Al avoidance by Mucuna roots is related to P preference.
    Verslag van de bijeenkomst van de Sektion Waldernaehrung im Deutschen Verband Forstlicher Forschungsanstalten te Freiburg i. Br. (Baden - Wuerttemberg) 2 t/m 4 oktober 1990 : "Salzduengung oder Kalkung in geschaedigten Waldoekosystemen?"
    Burg, J. van den - \ 1990
    Wageningen : De Dorschkamp (Rapport / De Dorschkamp Instituut voor Bosbouw en Groenbeheer nr. 628) - 70
    bosbouw - bomen - bosschade - bodemeigenschappen - achteruitgang, bossen - levensvatbaarheid - aluminium - atmosfeer - luchtverontreiniging - chemicaliën - calcium - Duitsland - Picea abies - bosopstanden - bemesting - forestry - trees - forest damage - soil properties - forest decline - viability - aluminium - atmosphere - air pollution - chemicals - calcium - Germany - Picea abies - forest stands - fertilizer application
    De betekenis van de aluminiumconcentratie in het wortelmilieu voor de groei en de minerale voeding van enkele boomsoorten : een literatuurstudie
    Burg, J. van den - \ 1990
    Wageningen : "De Dorschkamp" Instituut voor Bosbouw en Groenbeheer (Rapport / "De Dorschkamp" Instituut voor Bosbouw en Groenbeheer nr. 580) - 468
    bosbouw - bodemchemie - bodemaciditeit - verzuring - beluchting - voedingsstoffenopname (planten) - bodem pH - bodem - metaalelementen - mineralen - as - planten - mineraalgehalte - aluminium - overzichten - forestry - soil chemistry - soil acidity - acidification - aeration - nutrient uptake - soil pH - soil - metallic elements - minerals - ash - plants - mineral content - aluminium - reviews
    Lange-termijn effecten van verschillende depositiescenario's op representatieve bosbodems in Nederland
    Vries, W. de; Kros, J. - \ 1989
    Wageningen : Staring Centrum (Rapport / Staring Centrum 30) - 89
    bosbouw - verzuring - bodem pH - bodemaciditeit - bodem - metaalelementen - zure gronden - kattekleigronden - neerslag - zure regen - zure depositie - aluminium - modellen - onderzoek - chemische eigenschappen - zuurgraad - Nederland - computersimulatie - simulatie - simulatiemodellen - forestry - acidification - soil pH - soil acidity - soil - metallic elements - acid soils - acid sulfate soils - precipitation - acid rain - acid deposition - aluminium - models - research - chemical properties - acidity - Netherlands - computer simulation - simulation - simulation models
    Om inzicht te krijgen in het lange-termijn effect van verschillende depositiescenario's op bosbodems zijn simulaties uitgevoerd gedurende een periode van 100 jaar met het regionale bodemverzuringsmodel RESAM, dat in het kader van het Nationaal Programma Zure Regen is ontwikkeld
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