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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On the role of soil organic matter for crop production in European arable farming
Hijbeek, Renske - \ 2017
University. Promotor(en): Martin van Ittersum, co-promotor(en): Hein ten Berge. - Wageningen : Wageningen University - ISBN 9789463436632 - 211
soil fertility - soil fertility management - soil management - soil conservation - organic matter - soil organic matter - nitrogen - nitrogen fertilizers - green manures - manures - straw - soil carbon sequestration - cover crops - crop yield - yields - meta-analysis - food security - europe - drivers - barriers - bodemvruchtbaarheid - bodemvruchtbaarheidsbeheer - bodembeheer - bodembescherming - organische stof - organisch bodemmateriaal - stikstof - stikstofmeststoffen - groenbemesters - mest - stro - koolstofvastlegging in de bodem - dekgewassen - gewasopbrengst - opbrengsten - meta-analyse - voedselzekerheid - europa - chauffeurs - barrières

The aim of this thesis was to improve understanding of the role of organic inputs and soil organic matter (SOM) for crop production in contemporary arable farming in Europe. For this purpose, long-term experiments were analysed on the additional yield effect of organic inputs and savings in mineral fertiliser. In addition, a farm survey was conducted to find drivers and barriers for the use of organic inputs and to assess if arable farmers in Europe perceive a deficiency of SOM.

The findings in this thesis suggest that at least on the shorter term, on average, there seems to be no immediate threat from a deficiency of SOM to crop production in arable farming in Europe. The long-term experiments showed that with sufficient use of only mineral fertilisers, on average, similar yields could be attained over multiple years as with the combined use of organic inputs and mineral fertiliser. This was reflected in the farm survey, in which a large majority of farmers indicated not to perceive a deficiency of SOM. Analysis of long-term experiments also showed that more mineral fertiliser N was saved when using farmyard manure at high N rates (with mineral fertiliser application) than at low N rates (without mineral fertiliser application), based on comparisons at equal yield.

Specific crops and environments did benefit from organic inputs and more SOM in terms of crop production. Long-term experiments showed that organic inputs give benefit to crop production in wet climates and on sandy soils. In addition, farmers perceived a higher deficiency of SOM on steep slopes, sandy soils, wet and very dry climates. The additional yield effect of organic inputs was significant for potatoes. More in general, farmers who cultivated larger shares of their land with specialized crops (including potatoes, sugar beets, onions and other vegetables) than cereals perceived a higher deficiency of SOM. It seems that while the functions of SOM can be replaced with technical means to a large extent (e.g. tillage, use of mineral fertilisers), there are limits to this technical potential when environmental conditions are more extreme and crops are more demanding.

The farm survey revealed that farmers perceive a trade-off between improved soil quality on the one hand and increased pressures from weeds, pests and diseases and financial consequences on the other hand when using organic inputs. If policies aim to stimulate the maintenance or increase of SOM, more insight is needed into the conditions that regulate the pressures of weeds, pests and diseases in response to organic inputs. Financial consequences (at least on the short term) should also be accounted for. More importantly however, benefits from SOM for crop production cannot be taken for granted. Only in specific situations such benefits will exist. If European policies on SOM aim to include benefits for crop production, focus should be on areas with more extreme environmental conditions (very dry or wet climates, steep slopes, sandy soils), or cropping systems with more specialized or horticultural crops rather than cereals.

It depends: : effects of soil organic matter in aboveground-belowground interactions in agro-ecosystems
Gils, Stijn Herman van - \ 2017
University. Promotor(en): Wim van der Putten; David Kleijn. - Wageningen : Wageningen University - ISBN 9789463436526 - 176
soil organic matter - agroecosystems - aphidoidea - fertilizers - wheat - rape - crop yield - ecosystem services - nutrient availability - pest control - organic farming - organisch bodemmateriaal - agro-ecosystemen - kunstmeststoffen - tarwe - koolzaad - gewasopbrengst - ecosysteemdiensten - voedingsstoffenbeschikbaarheid - plagenbestrijding - biologische landbouw

Over the last decades agricultural production increased drastically due to the use of external inputs. However, the use of external inputs has high environmental costs and may negatively influence ecosystem processes such as pollination and pest control that underpin agricultural production. Soil organic matter has been proposed as a potential alternative to external inputs as it relates to multiple yield promoting ecosystem processes. The aim of my thesis is to assess whether and how soil organic matter content alters the effect of some ecosystem processes and external inputs on crop yield. I examined whether soil organic matter alters biomass of wheat and oilseed rape under fertilizer supply. Other biotic and abiotic factors that operate at different spatial and temporal scales are also included in some of these experiments. I found that under controlled conditions soil organic matter may reduce the positive effect of mineral fertilizer supply on crop biomass. The reduction changed with the presence or absence of a pathogenic root fungus, but not with drought stress. Moreover, soil organic matter enhances performance of aphids under controlled greenhouse conditions, but the enhancement was less than fertilizer supply. None of these controlled experiments, however, showed that soil organic matter can be an alternative to mineral fertilizer supply. Under field conditions soil organic matter did not strongly affect plant nutrient availability or performances of aphid and its natural enemies. The relation between soil organic matter and plant biomass in a greenhouse experiment did not change with organic management or the duration of it, neither did it change with pollinator visitation rate, an ecosystem process that is managed on the landscape scale. These results suggest that soil organic matter may relate to ecosystem services that influence crop yield, whereas these relations might not be significant under field conditions. Collectively, all these results suggest that the relation between soil organic matter content and ecosystem processes that benefit crop yield is highly context dependent. I propose future research may focus on (1) the quality of soil organic matter rather than the content per se and (2) the relation between soil organic matter content and crop yield under realistic conditions in a longer term.

Research for AGRI Committee : preserving agricultural soils in the EU - Study
Berge, H.F.M. ten; Schroder, J.J. ; Olesen, Jørgen Eivind ; Giraldez Cervera, J.V. - \ 2017
Brussels : European Parliament - ISBN 9789184609550 - 135 p.
soil management - soil quality - european union - soil organic matter - biodiversity - agriculture - organic farming - bodembeheer - bodemkwaliteit - europese unie - organisch bodemmateriaal - biodiversiteit - landbouw - biologische landbouw
This study explains how threats to soils and soil services are linked to agricultural soil management, how threats can be mitigated, and which barriers complicate this. It highlights trade-offs and synergies that exist between different interests affected by soil management, such as climate change mitigation, water and air quality, biodiversity, food security and farm income. Conservation of peatland and extensive agro-forestry systems, and protecting soils against sealing, erosion and compaction are ranked as highest priorities. Potential policy elements are suggested.
Selenium speciation and bioavailability in Dutch agricultural soils: the role of soil organic matter
Supriatin, Supriatin - \ 2016
University. Promotor(en): Rob Comans, co-promotor(en): Liping Weng. - Wageningen : Wageningen University - ISBN 9789462579309 - 265
agricultural soils - selenium - bioavailability - soil organic matter - grasslands - soil chemistry - fertilizers - fertilizer application - netherlands - landbouwgronden - biologische beschikbaarheid - organisch bodemmateriaal - graslanden - bodemchemie - kunstmeststoffen - bemesting - nederland

Selenium (Se) is an essential micronutrient for animals and humans. In the food chain, the intake of Se by animals and humans depends largely on Se content in plants, whereas the major source of Se in plants lies in the soil. Therefore, understanding Se bioavailability in soils for plant uptake and its controlling factors and mechanisms is important. The objective of this thesis is to study the amount, speciation, bioavailability, plant uptake and fertilization of Se in agricultural soils in the Netherlands and underlying controlling factors and mechanisms, to provide guidance for soil testing and fertilization recommendation for efficient Se management in agriculture.

The majority of agricultural soils (grassland and arable land) in the Netherlands contains low total Se (i.e. in the range of Se deficient), which is predominantly present as organic Se. Only a small fraction of total Se is present as inorganic Se (mainly as selenite) and residual Se. In this thesis, the evidences of association between Se and soil organic matter in these low Se soils have been shown. The associations include: (1) the total Se content is positively correlated to soil organic matter content; (2) the solubility and extractability of Se in soils follow the solubility and extractability of soil organic C; (3) the majority of Se present in soils is in organic form, both in the soil solution and solid phase; (4) the distributions of Se and organic C in the different fractions of solid organic matter (i.e. humic acids, hydrophobic organic neutral, hydrophilic acids) and dissolved organic matter (i.e. hydrophilic acids and fulvic acids) are comparable; and (5) the Se richness in solid and dissolved organic matter are related to properties of soil organic matter from different land uses. The relatively high soil organic matter content in these low Se soils is likely responsible for these associations.

In general, Se content in crops (e.g. grass and wheat) grown on grassland soils and arable land soils, respectively in the Netherlands is low due to low amount of bioavailable Se in the soils. Different soil parameters determine Se plant uptake in these low Se soils with predominantly organic Se, depending on the properties of Se-containing soil organic matter. The intensity parameter of Se-rich dissolved organic matter (DOM) in soil solution (i.e. Se to DOC ratio in 0.01 M CaCl2 extraction) determines Se plant uptake in soils containing Se-rich organic matter (e.g. potato arable land soils), whereas the buffer capacity of labile organic Se to supply Se-rich DOM in soil solution limits Se plant uptake in soils containing Se-poor organic matter (e.g. grassland soils). Further research is needed to confirm the generality of the conclusion above, because the two experiments were carried out under different conditions (pot experiment and field experiment), using different plant species (wheat and grass) and covering different soil types from different land uses (potato fields and grassland). Site-specific properties in the field in addition to soil parameters included in the current study may largely (> 50%) determine Se content in grass under field conditions, which is in contrast with the results of the pot experiment in which the soil parameter explains 88% of Se content in wheat shoots. In general, the content of Se-rich DOM in soils increases with the increase of soil pH (with the decrease of soil C:N ratio), and the amount of labile organic matter in soils that can resupply Se-rich DOM is determined by the amount of clay (and Fe-(hydr)oxide). NPK fertilization, as one of the external factors, can reduce Se plant uptake, especially in organic-rich soils.

Selenium (as selenate) fertilization on grassland with N plus cattle slurry or NPK application shows a positive effect to increase Se content in grass grown on different soil types with a large range of total Se, pH, clay content and organic matter content. Selenium content in grass grown on different soil types upon Se fertilization becomes more similar than before the fertilization. The results indicate that the effectiveness of Se fertilization is only weakly modified by soil properties, probably due to the high solubility of selenate in the soils. Nevertheless, the Se fertilization tends to be slightly more effective on sandy soils than on clay and organic rich soils.

This thesis has shown that the content and quality of soil organic matter play an important role in determining the amount, speciation and bioavailability of Se in low Se soils with predominantly organic Se. The results in this thesis can be used as guidance to develop soil testing and fertilization recommendation for efficient Se management, especially in low Se soils with predominantly organic Se, such as in Dutch agricultural soils.

Soil organic matter in the Netherlands : Quantification of stocks and flows in the top soil
Conijn, J.G. ; Lesschen, J.P. - \ 2015
Wageningen : Plant Research International, Business Unit Agrosystems Research (Report / Plant Research International 619) - 50 p.
soil organic matter - carbon - nutrient balance - arable farming - arable land - netherlands - organisch bodemmateriaal - koolstof - voedingsstoffenbalans - akkerbouw - bouwland - nederland
Soil organic matter (SOM) and especially decreasing SOM are since many decades on the agenda of different stakeholders due to the importance of SOM for various issues ranging from local crop profitability to global climate change. Globally large amounts of organic carbon are stored in the soil and changes in the amount of SOM may sequester or release CO2 from/into the atmosphere. The global stock of soil organic carbon (SOC) in the upper 100 cm equals roughly two times the amount of carbon in the atmosphere and soil respiration equals circa ten times the release of carbon by burning fossil fuels. Other functions of SOM with a (more) local dimension relate to e.g. soil fertility, soil structure, soil erosion, regulation of soil water flows, plant productivity and maintenance of soil biodiversity. Declining SOM is considered as one of the most serious processes of soil degradation and has been identified as one of the main soil threats. Next to positive effects, decomposition of SOM may also have adverse effects by enhancing N2O and CH4 emissions, and releasing nutrients of which part is leached to surface and ground waters. In the Netherlands, the “Technische Commissie Bodem” (TCB) gives advice to the government on soil related issues and has recently developed an advice for the Dutch government on the effects of future trends (such as the biobased economy, climate change, safeguarding food productivity, water management) on soil functioning. As part of the information gathering underlying this advice, the TCB asked Plant Research International and Alterra to conduct a literature research of (a) SOM stocks, flows and recent trends, (b) variation and uncertainty in the data and (c) determination of areas of having/reaching low SOM levels in the Netherlands. In this study we have focussed on the top soil of 0-30 cm and mainly on soils under agricultural use. SOM in deeper soil layers may be important (e.g. globally the layer 30-100 cm contains approximately an equal amount of SOC as compared to the 0-30 cm layer), but due to lack of data this fell outside the scope of this study. The findings of this study have been presented to the working group “Koolstofstromen” of the TCB in three separate sessions in 2013-2014.
How does urbanization affect spatial variability and temporal dynamics of soil organic carbon in the Moscow region
Vasenev, V.I. - \ 2015
University. Promotor(en): Rik Leemans, co-promotor(en): Jetse Stoorvogel. - Wageningen : Wageningen University - ISBN 9789462575899 - 214
organische koolstof - organisch bodemmateriaal - urbanisatie - stadsomgeving - emissie - stedelijke ecologie - stadsgronden - rusland - organic carbon - soil organic matter - urbanization - urban environment - emission - urban ecology - urban soils - russia
Tot de bodem uitzoeken : micro-organismen beïnvloeden plantengroei
Beintema, N. ; Groenigen, J.W. van - \ 2015
WageningenWorld (2015)2. - ISSN 2210-7908 - p. 10 - 15.
bodembiologie - bodembeheer - organische stof - aardwormen - bodemkwaliteit - organisch bodemmateriaal - koolstof - micro-organismen - bodemvruchtbaarheid - gewasbescherming - plantenontwikkeling - soil biology - soil management - organic matter - earthworms - soil quality - soil organic matter - carbon - microorganisms - soil fertility - plant protection - plant development
Per vierkante meter bodem leven honderden wormen en insecten samen met kilometers aan schimmeldraden, vele miljoenen aaltjes en miljarden bacteriën. Onderzoek maakt steeds meer duidelijk van het precaire evenwicht ondergronds, en de grote invloed daarvan op het leven bovengronds. Het levert nieuwe strategieën op voor gewasbescherming.
Soil and plant responses to pyrogenic organic matter: carbon stability and symbiotic patterns
Sagrilo, E. - \ 2014
University. Promotor(en): Thomas Kuijper; Ellis Hoffland. - Wageningen : Wageningen University - ISBN 9789462571679 - 128
organisch bodemmateriaal - grondverbeteraars - koolstofvastlegging in de bodem - vesiculair-arbusculaire mycorrhizae - bodemvruchtbaarheid - glycine max - biochar - stikstoffixatie - kooldioxide - emissie - brazilië - soil organic matter - soil amendments - soil carbon sequestration - vesicular arbuscular mycorrhizas - soil fertility - nitrogen fixation - carbon dioxide - emission - brazil

Soil and plant responses to pyrogenic organic matter: carbon stability and symbiotic patterns

Edvaldo Sagrilo

Summary

Pyrogenic organic matter (PyOM), also known as biochar, is the product of biomass combustion under low oxygen concentration. There is currently a growing interest in research on the use of PyOM as a soil amendment, inspired by the existence of highly fertile, PyOM-rich anthropogenic soils in the Amazon basin. The presence of PyOM in these so-called Amazonian Dark Earths (ADE) in quantities larger than in the non-anthropogenic surrounding soils is considered one of the main reasons for their high fertility.

Soil additions of PyOM have been suggested to increase soil fertility and crop yields, simultaneously providing additional important environmental services. The offset of CO2 emissions through sequestration of a larger pool of recalcitrant soil organic carbon (SOC) is one of these services. This would at the same time sustain soil microbial activity, which is directly associated to soil quality, for instance, nutrient cycles and plant growth. This multiple win scenario suggests that the addition of PyOM to the soil would be the solution for the “carbon dilemma”. The dilemma states that the main biological benefits from soil organic matter are a consequence of its decay. Therefore, it is unlikely that increased C sequestration and the benefits from its decay can be simultaneously maximized. Rather than win-win, PyOM would then also be subjected to inevitable trade-offs.

Additions of PyOM can modify the turnover rate of native SOC by either accelerating or decelerating its decomposition through a mechanism known as priming. Although positive priming by PyOM has been reported, negative priming has also been found. The higher amount of non-pyrogenic C in ADE, compared to non-anthropogenic surrounding soils has been considered evidence that PyOM can stabilize SOC in the long-term. A complicating issue in studies is that short-term increases in CO2 emission can be due to decomposition of labile PyOM fractions, erroneously suggesting positive priming of SOC. Addition of PyOM can also lead to modifications in the microbial activity and assemblages. Changes in microbial populations can have impacts on their functionality, favouring mutualistic root symbioses such as the arbuscular mycorrhizal fungal (AMF) symbiosis and the rhizobial symbiosis with legumes that is responsible for biological nitrogen fixation (BNF). Although soil amendments with PyOM can stimulate AMF and BNF, results are contrasting and mechanisms are not clear. Most studies of PyOM effects on SOC and on mutualistic root symbioses are from short-term experiments, often conducted in greenhouse or laboratory. Although such studies provide insights in potential factors driving changes in SOC and symbiotic relationships in PyOM-amended soils, they do not assess changes under realistic conditions over periods of time longer that one or a few cropping cycles. Therefore, there is still a gap in our understanding regarding the duration and magnitude of effects over time under field conditions and possible mechanisms involved. This thesis addresses these gaps.

The aim of this research was to provide a better understanding of interactions between PyOM and SOC and the factors controlling symbiotic patterns in a tropical soil amended with PyOM. To reach this aim, I combined greenhouse and field studies. I also used meta-analytic methods in order to quantitatively synthesize data in literature.

In Chapter 2, I combined the results of 46 studies in a meta-analysis. I investigated changes in CO2 emission patterns from an array of PyOM-amended soils and identified the causes of these changes and the possible factors involved. I showed an overall increase of 29% in CO2 emission from PyOM-amended soils. Such increases were only evident in soils amended with a PyOM-C (PyC):SOC ratio >2. These data are consistent with the hypothesis that increased CO2 emission after PyOM addition is additive and mainly derived from PyOM’s labile C fractions rather than from SOC. Therefore, positive priming is not a main driver of increases in CO2 emission in PyOM-amended soils. This PyC:SOC ratio provided the best predictor of increases in CO2 production after PyOM addition to soil. This meta-analysis indicates (i) the importance of taking into account the amount of applied PyC in relation to SOC for designing future decomposition experiments and that (ii) the recalcitrance of PyOM in soil-PyOM mixtures may be less than usually assumed.

A technical problem of separating PyOM-induced priming on SOC from other non-additive interactions is the uncertainty regarding the origin of the respired CO2 (whether from SOC or PyOM). This issue can only be solved with the use of isotopes. In a field study (Chapter 3), I quantified changes in the PyOM and SOC stocks over four soybean cropping cycles (CC) in a sandy Ferralsol, previously supporting a vegetation with C4 plants, amended with different rates of PyOM (0, 5, 10, 20 and 40 Mg ha-1). The PyOM was produced from C3 woody species using traditional pyrolysis methods employed in Northeast Brazil. I used 13C isotopic analysis to discriminate the origin of the C in the soil and quantify the decomposition rates of native SOC and PyOM. I showed that decomposition of traditionally produced PyOM is faster (25-60% within first year) than normally assumed (10-20% within 5-10 years), which was higher than that of native SOC (5-14%). The data indicate preferential decomposition of PyOM compared to native SOC. The intensity of that effect depends on the rate of PyOM applied to the soil. Only on the longer term (>1 yr) addition of PyOM seems to stabilize SOC.

In Chapter 4 I explored mechanisms controlling AMF activity and crop yield in PyOM-amended soils through the use of path analysis. I tested the effects of PyOM rates and P fertilization on soybean root colonization by AMF, soil P and plant performance over four cropping cycles (CCs). Data showed a major effect of CC and P, as well an interaction effect of PyOM x CC on mycorrhizal colonization. There was a linear decrease in root colonization by AMF in CC1 with increasing PyOM rates in contrast to a consistent linear increase in CC4. Plant performance was mainly affected by CC, but a significant interactive effect of PyOM x P was also observed on grain yield. Grain yield was highest at high PyOM rates (20 and 40 Mg ha-1) in the P-fertilized treatments in CC4. Soil pH increased in CC1 with increasing PyOM rates, but no effects were observed in CC4. Path analysis indicated that PyOM effects on root colonization by AMF were not mediated by changes in soil pH or P content. My data are consistent with the hypothesis that interference of PyOM in signalling processes is an important driver of change in AMF activity and that positive effects of PyOM on AMF and crop yield develop with time.

In Chapter 5, I assessed the effects of PyOM application rates and P fertilization on BNF in soybean inoculated with Bradyrhizobium japonicum over four cropping cycles. Again I observed that CC had a significant main effect on most dependent variables, while PyOM was not a significant source of variation. There was a significant PyOM × CC interaction effect on shoot N concentration. In CC1 shoot N concentration after application of 5 Mg PyOM was significantly lower than that of plants grown on plots to which 10 or 20 Mg PyOM was applied. In CC4 shoot N concentration was not affected by PyOM. The major effect of CC was explained through changes in nutrient management, more specifically the addition of micronutrients in CC3 and CC4. Alleviation of micronutrient deficiency increased BNF and also resulted in a positive effect of P on BNF. I conclude that under conditions of adequate management, PyOM application does not improve BNF in soybean.

In Chapter 6 (General Discussion) I synthesize the findings of the previous chapters and use data from additional greenhouse and litterbag field experiments to integrate the results. Data from Chapters 2 and 3 show that if any positive priming occurs due to PyOM addition, it is a small short-term event and does not lead to significant losses of native SOC in the long-term. This was confirmed by data from a 2 yr litterbag experiment, which showed no interaction between decomposition of PyOM and fresh organic matter.

Stability of SOC has been considered an ecosystem property rather than a consequence of recalcitrance, but this definition has not yet been extended to PyOM. In this thesis I demonstrated that stability of PyOM can also be influenced by the soil environment. In order to link PyOM effects to SOC and on root symbioses, I performed path analysis integrating root colonization by AMF, SOC content and Ndfa in one model. We found no significant path coefficients linking AMF and BNF. The model indicated a significant positive path coefficient linking AMF root colonization and SOC in CC4, but not in CC1. The data suggest that PyOM may increase SOC stability through increased AMF activity. Soil aggregation and C sequestration are tightly correlated with abundance of AMF in the soil. I propose that the same mechanism through which AMF stabilizes native SOC may also positively influence PyOM stabilization in the long-term.

In conclusion, I have shown that main beneficial effects of PyOM on AMF and crop yield develop with time, but in well-managed soils increased crop yield is not a direct consequence of increased AMF due to PyOM addition. Finally, although PyOM additions represent an effective form of sequestering C, positive effects of PyOM on crop yield are likely to occur after partial decomposition of PyOM. Therefore, although some benefits of adding PyOM can be simultaneously obtained (C sequestration and increased crop yield), they cannot be simultaneously maximized. This means that the carbon dilemma can only be partially solved by adding PyOM to the soil.

EIP-AGRI Focus Group; Protein Crops: final report
Schreuder, R. ; Visser, C.L.M. de - \ 2014
EIP-AGRI - 49
organische meststoffen - organisch bodemmateriaal - middellandse-zeegebied - innovaties - duurzaamheid (sustainability) - bodemvruchtbaarheid - peulvruchten - akkerbouw - kennisoverdracht - teeltsystemen - organic fertilizers - soil organic matter - mediterranean region - innovations - sustainability - soil fertility - grain legumes - arable farming - knowledge transfer - cropping systems
This report is the result of the EIP-AGRI Focus Group (FG) on Soil organic matter (SOM) content in Mediterranean regions, which was launched under the European Innovation Partnership Agricultural Productivity and Sustainability (EIP-AGRI). The Focus Group brought together 19 experts with different backgrounds and experiences to make recommendations on transferable innovative solutions for the purpose of improving soil organic matter content in the Mediterranean region in a cost-effective way while securing soil functionality and soil fertility in the specific context of Mediterranean regions
On soil organic matter dynamics in species-diverse grasslands and intercrop systems
Cong, W. - \ 2014
University. Promotor(en): Ellis Hoffland, co-promotor(en): Wopke van der Werf; F.S. Zhang. - Wageningen : Wageningen University - ISBN 9789462570184 - 158
organisch bodemmateriaal - graslanden - broeikasgassen - teeltsystemen - bodemchemie - biomassa productie - ecosysteemdiensten - bodemkwaliteit - landgebruik - soil organic matter - grasslands - greenhouse gases - cropping systems - soil chemistry - biomass production - ecosystem services - soil quality - land use
Door menselijk handelen (verandering in van natuurlijke vegetatie naar landbouw) is de organische C voorraad in de bodem met 10-59% afgenomen, afhankelijk van de landgebruiksverandering. Dit heeft geleid tot een toename van de CO2 concentratie in de atmosfeer. Deze toename heeft bijgedragen aan opwarming van de aarde en de daaraan gerelateerde milieuproblemen. Een ander risico van de vermindering van de organische C voorraad in de bodem is vermindering van de bodemvruchtbaarheid. Mede hierdoor wordt de opgave om de voedselproductie de komende 50 jaar te verdubbelen, een grote uitdaging. Vastlegging van C in de bodem kan een goedkope en milieuvriendelijke maatregel zijn die bijdraagt aan vermindering van effecten van klimaatverandering op een termijn van 20 – 50 jaar. Deze maatregel kan bovendien bijdragen aan voedselzekerheid doordat ze de bodemkwaliteit in landbouwsystemen verhoogt.
Panarchy rules? : rethinking resilience of agroecosystems
Apeldoorn, D.F. van - \ 2014
University. Promotor(en): Ken Giller, co-promotor(en): Kasper Kok; Marthijn Sonneveld. - Wageningen : Wageningen University - ISBN 9789461739179 - 137
agro-ecosystemen - duurzaamheid (sustainability) - bedrijfssystemen - organisch bodemmateriaal - wiskundige modellen - systeemanalyse - nederland - zimbabwe - agroecosystems - sustainability - farming systems - soil organic matter - mathematical models - systems analysis - netherlands

This thesis explores the applicability of the resilience perspective on agro-ecosystems dynamics. It start out by using the five heuristics of the resilience perspective on intensive agricultural systems. Simulations with a dynamic farm model suggest that conventional farming short cuts the adaptive cycle leading to an ‘incremental adaptation’ trap. Panarchy is therefore claimed as a leading heuristic to understand long-term dynamics and current management characteristics. This interaction of long-term dynamics with current management leads to an asymmetry in the landscape. This asymmetry leads to windows of opportunities for farmers. However, disregarding the cross-scale nature of the asymmetry might also lead to a cascade of events that undermine the resilience of the landscape as whole. The cross-scale interactions of landscape dynamics and farm management suggest a co-evolution of production intensity and landscape pattern. Moreover trajectories of intensification might even be linked to certain tipping points of combinations of landscape characteristics and management. Therefore the landscape asymmetry might yield insight in agro-ecosystem functioning. The landscape asymmetry potentially provides a level of self-organisation above the farm. However, identifying the asymmetry appeared to be problematic. Next to scale issues, the current pattern does not necessary result from current management, leading to a de-coupling of pattern and process. A re-coupling of management and landscape asymmetry can exploit positive feedbacks. I suggest the use of identity to locate asymmetries and to use space-time substitutions to experiment with the typical slow variables that shape the asymmetry.

The theory developed in this thesis is grounded on empirical farm management data and dynamical model simulation of intensive dairy farming in the Netherlands and small-holder systems in Zimbabwe.

Mechanistic modelling of the vertical soil organic matter profile
Braakhekke, M.C. - \ 2014
University. Promotor(en): Pavel Kabat, co-promotor(en): C. Beer; M. Reichstein; Marcel Hoosbeek. - Wageningen : Wageningen University - ISBN 9789461738288 - 190
organisch bodemmateriaal - bodemprofielen - modelleren - modellen - bayesiaanse theorie - soil organic matter - soil profiles - modeling - models - bayesian theory

Soil organic matter (SOM) constitutes a large global pool of carbon that may play a considerable role for future climate. The vertical distribution of SOM in the profile may be important due to depth-dependence of physical, chemical, and biological conditions, and links to physical processes such as heat and moisture transport. The aim of this thesis is to develop a dynamic and mechanistic representation of the vertical SOM profile that can be applied for large scale simulations as a part of global ecosystem and earth system models.

A model structure called SOMPROF was developed that dynamically simulates the SOM profile based on above and below ground litter input, decomposition, bioturbation, and liquid phase transport. Furthermore, three organic surface horizons are explicitly represented.

Since the organic matter transport processes have been poorly quantified in the past and are difficult to observe directly, the model was calibrated with a Bayesian approach for two contrasting temperate forest sites in Europe. Different types of data were included in the parameter estimation, including: organic carbon stocks and concentrations, respiration rates, and excess lead-210 activity.

The calibrations yielded good fits to the observations, and showed that the two sites differ considerably with respect to the relevance of the different processes. These differences agree well with expectations based on local conditions. However, the results also demonstrate the difficulties arising from convolution of the processes. Several parameters are poorly constrained and for one of the sites, several distinct regions in parameter space exist that yield acceptable fit.

In a subsequent study it was found that radiocarbon observations can offer much additional constraint on several parameters, most importantly on the turnover rate of the slowest SOM fraction. Additionally, for one site, a prognostic simulation until 2100 was performed using the resulting a posterioriparameter distribution, This showed that different parts of the SOM profile can respond differently to increasing temperatures and litter input.

In conclusion, the SOMPROF model, combined with the Bayesian calibration scheme, offers valuable insights into the relevance of the different mechanisms to the SOM profile. However, equifinality remains a challenge, particularly for distinguishing different SOM transport processes. Improved representation of liquid phase transport and incorporation of additional observations may reduce these problems. In the future, SOMPROF can be incorporated into a terrestrial ecosystem model and calibration results can be used when deriving parameter sets for large scale application.

Unravelling changes in soil fertility of agricultural land in The Netherlands
Reijneveld, J.A. - \ 2013
University. Promotor(en): Oene Oenema; Aad Termorshuizen. - Wageningen : Wageningen UR - ISBN 9789461737793 - 227
bodemvruchtbaarheid - landbouwgrond - organisch bodemmateriaal - bodemonderzoek - koolstof - fosfor - nederland - soil fertility - agricultural land - soil organic matter - soil testing - carbon - phosphorus - netherlands

Keywords:

Soil fertility, soil test, phosphorus, soil organic matter, soil organic carbon, fertilization recommendation, data base, the Netherlands

On fertile soils, high-yielding crop production systems can be built which are indispensable both for profitable farming and for feeding the steadily increasing world population. With its high soil fertility, agriculture in the Netherlands is one of the most productive in the world. The high soil fertility is partly inherited from sea and rivers, partly it is men-made through manure and fertilizer applications. However, from the 1980s manure and fertilizer applications are limited through governmental regulations.

This thesis aims to increase the understanding of spatial variations and changes over time in soil fertility of farmers’ fields in the Netherlands during the last century. More specifically, it addresses the following research questions: i) which changes have taken place in soil organic matter (SOM) and soil phosphorus (P) contents in the period 1970 to 2000s, ii) will mean soil P status develop towards the optimal agricultural range, with a small standard deviation when virgin soil is cultivated with high craftsmanship?, iii) how did herbage quality respond to changes in mean soil fertility in dairy farming, iv) what are farmers’ perceptions and concerns regarding soil fertility?, and v) how to improve the usability of fertilization recommendations, using new knowledge? A large data base of a laboratory for routine soil, manure, herbage tests (BLGG) was analysed statistically, and a questionnaire was conducted.

Results show that the mean SOM content of mineral soils remained stable during the last decades, despite worldwide reports about declining SOM contents, and concerns expressed by farmers. Restrictions on the use of animal manure did not yet have an effect on dairy farms; soil P status of grassland and mineral content of herbage remained within the optimal range during the last few decades, but crude protein decreased. Soil P status on arable land increased until the 2000s, partly to above agronomical optimal ranges. Risk avoidance seems a decisive factor for pursuing these higher statuses, stressing the need for improved recommendations. Since implementing new insights proves hard, a three-step schedule for incorporating results of novel soil tests into fertilization recommendations is suggested. Farmers endorse the importance of soil fertility and SOM, and P status should be monitored, including anticipated information about soil structure and soil life.

Overleving van komkommerbontvirus (CGMMV) in verschillende milieus
Stijger, I. ; Hamelink, R. - \ 2012
Bleiswijk : Wageningen UR Glastuinbouw (Rapport / Wageningen UR Glastuinbouw ) - 21
komkommerbontvirus - plantenziekten - cucumis sativus - verspreide infecties - gewasbescherming - ontsmettingsmiddelen - bedrijfshygiëne - organisch bodemmateriaal - tests - effecten - cucumber green mottle mosaic virus - plant diseases - disseminated infections - plant protection - disinfectants - industrial hygiene - soil organic matter - effects
Komkommerbontvirus is een virus dat via mechanische overdracht en zaad kan worden verspreid. Via sap van geïnfecteerde planten kan bij alle gewashandelingen zoals indraaien, snoeien en oogsten het virus worden overgedragen op gezonde planten. Verspreiding van het virus is mogelijk via besmet materiaal zoals mesjes, scharen, kleding en fust. Het virus kan overblijven in gewasresten zoals bladeren, wortels en vruchten. Grote vraag is of er ook andere bronnen voor een nieuwe infectie met komkommerbontvirus zijn? Doel van het onderzoek is om praktische kennis voor de telers te vergaren die direct toepasbaar is en antwoord geeft op de in de praktijk levende vragen.
Soil organic carbon stocks and changes upon forest regeneration in East Kalimantan- Indonesia
Yassir, I. - \ 2012
University. Promotor(en): Pavel Kabat, co-promotor(en): Peter Buurman; Bram van Putten. - S.l. : s.n. - ISBN 9789064645761 - 175
natuurlijke verjonging - tropische bossen - imperata cylindrica - secundaire bossen - koolstofvastlegging in de bodem - organisch bodemmateriaal - bodemeigenschappen - vegetatie - plantensuccessie - kalimantan - indonesië - natural regeneration - tropical forests - secondary forests - soil carbon sequestration - soil organic matter - soil properties - vegetation - ecological succession - indonesia

Imperata grassland is a common vegetation type in Kalimantan (Indonesia), and other parts of South-East Asia. It indicates a high degree of degradation of the vegetation, and mostly occurs after slashing and burning of primary forest. Through secondary succession Imperata grassland is converted into new secondary forest and much of the original biodiversity is restored. The overall objective of the thesis was to study the regeneration of Imperata grasslands in East Kalimantan, and to measure the effects of regeneration on soil properties, with emphasis on the organic fraction. The research strategy was to compare plots of different regeneration stages, characterized by the period elapsed since the vegetation was last burned.
Results show that during regeneration of Imperata grasslands, both vegetation composition and soil properties change, including chemistry of soil organic matter. Soil carbon stocks are higher under Imperata grasslands than under primary forest, and increase further upon natural regeneration of grassland to secondary forest. Highest carbon stocks are found in the later regeneration phases. Lower carbon stocks under primary forests are due to extremely low fertility, combined with shallow soils and low root mass in the topsoil. Root density as observed in the field is much higher under the grass vegetation. Results show as well that soil organic matter decomposition is most advanced under forest, as indicated by lower amounts of plant derived compounds and higher contribution of microbial matter. The results indicate that decomposition efficiency is related to soil organic matter chemistry, but more to abundance of N-compounds than to that of potentially recalcitrant compounds.
In our case study, soil texture appears an important factor in the vegetation succession. On sandy soils, there is a strong increase with time of Pteridium aquilinum L., while the number of other species is lower. This slows down the development towards secondary forest. Canonical correspondence analysis (CCA) of environmental factors and vegetation show that pH, bulk density, sand and clay are the factors related to the distribution of species. The rapid secondary succession indicates that Imperata grasslands are not a final and stable stage of land degradation, but that frequent fires are necessary to maintain Imperata grasslands. If protected from fire and other intrusions such as shifting cultivation, Imperata grassland will readily develop into secondary forest. Imperata grasslands seem to be permanent because of human interference, especially through burning, and because so far few attempts have been made to sustainable rehabilitation.

Scientific arguments for net carbon increase in soil organic matter in Dutch forests
Mol, J.P. ; Wyngaert, I.J.J. van den; Vries, W. de - \ 2012
Wageningen : Alterra (Alterra-report 2324) - 32
organisch bodemmateriaal - bosgronden - bossen - koolstofvastlegging - nederland - soil organic matter - forest soils - forests - carbon sequestration - netherlands
If reporting of emissions associated with Forest Management becomes obligatory in the next commitment period, the Netherlands will try to apply the 'not-a-source' principle to carbon emissions from litter and soil in land under Forest Management. To give a scientific basis for the principle of carbon stock change being 'not-a-source', a review is first made of the methods and arguments of other countries and the acceptance or disapproval by UNFCCC experts. Second, we investigated whether available Dutch datasets and literature information confirm the claim that Dutch forest soils are not a carbon source. This review indeed showed convincing arguments for soil being a carbon sink in the Netherlands under forest management, based on a combination of (i) measurements in Loobos, (ii) literature on soil carbon increases based on repeated measurement in comparable areas, (iii) N retention assessments, assuming that the soil C/N ratio stays constant, (iv) European scale modelling approaches on soil carbon changes including the Netherlands and (v) argumentation from expected changes in climate and N deposition in the Netherlands, combined with the results from meta-analysis and modelling.
Risk assessment methodologies of soil threats in Europe: status and options for harmonization for risks by erosion, compaction, salinization, organic matter decline and landslides
Ano-Vidal, C. ; Ehlert, P.A.I. ; Hagyo, A. ; Heesmans, H.I.M. ; Kuikman, P.J. ; Oenema, O. ; Recatala-Boix, L. ; Simota, C. ; Tóth, G. ; Beek van, C. ; Akker van de, J. ; Zee, S.E.A.T.M. van der; Verzandvoort, S. - \ 2012
Luxembourg : Publications Office of the European Union (JCR scientific and technical reports ) - ISBN 9789279142918 - 84
risicoschatting - methodologie - bodemdegradatie - erosie - bodemverdichting - verzilting - organisch bodemmateriaal - aardverschuivingen - europa - risk assessment - methodology - soil degradation - erosion - soil compaction - salinization - soil organic matter - landslides - europe
The EU thematic strategy for soil protection recognizes that soil degradation through erosion, soil organic matter decline, compaction, salinization and landslides occurs in specific areas, and that these areas must be identified in an unequivocal way. Currently, there are various risk assessment methodologies (RAMs) and the question has risen to what extent these RAMs yield similar outcome and, if not, whether the outcome can be harmonized, i.e. whether the results of the various RAMs can be made compatible or comparable. In this study i) the current status of RAMs for erosion, soil organic matter decline, compaction, and salinization in the European Union (EU27) is reviewed, and ii) the need and the options for harmonization are assessed. The need for harmonization was defined as the likelihood of achieving different outcomes when using different RAMs, whereas the options for harmonization refer to the efforts that are required to harmonize soil RAMs. The current status of RAMSs in EU-27 was assessed on the basis of questionnaires, which were sent out to soil specialists and policy officers in all Member States. We received more than 100 (response rate >50%) completed questionnaires. It turned out that many of the so called RAMs are still incomplete; they are ‘process (or threat) quantifications’ rather than methodologies that assess the risk of a soil threat. Moreover, there were significant differences between RAMs for a soil threat in terms of (i) the notion of the threat, (ii) data collection, (iii) data processing, (iv) data interpretation, and (v) risk perception. The need for harmonization appeared highest for erosion and salinization, whereas the options for harmonization were best for SOM decline. Harmonization of soil RAMs may be very complex and for that reason not always feasible. We suggest two options that may facilitate unequivocal identification of risk (or priority) areas for soil threats, i) a two Tiered approach based on data availability and spatial scale and ii) generic harmonization, i.e. combining standardization and harmonization in a rather pragmatic way
Biologische beheersing bonenvlieg 2010 2011
Broek, R.C.F.M. van den; Gruppen, R. ; Hootegem, A. - \ 2012
Lelystad : PPO AGV (Biokennis rapport 465)
biologische bestrijding - delia platura - plagenbestrijding - bestrijdingsmethoden - biologische landbouw - insectenplagen - veldproeven - vollegrondsgroenten - organisch bodemmateriaal - biological control - pest control - control methods - organic farming - insect pests - field tests - field vegetables - soil organic matter
In Zeeland zijn in 2010 en 2011 proeven aangelegd om de bonenvlieg op biologische wijze te beheersen. Percelen die in 2009 zijn aangetast door de bonenvlieg zijn bemonsterd en de aanwezige poppen van vliegen geteld. Deze percelen of percelen in de directe nabijheid zijn gebruikt voor onderzoek. Er zijn verschillende maatregelen onderzocht zoals het effect van middelen toegediend in de zaaivoor voor zaai, het moment van mesttoediening en type mest en het inwerken van een groenbemester.
Organische stof management in de sierteelt met speciale aandacht voor (duin)zandgrond : resultaten 2007-2011
Pronk, A.A. ; Leeuwen, P.J. van; Berg, H. van den - \ 2012
Wageningen : Plant Research International (Rapport / Plant Research International 438)
sierteelt - sierplanten - organisch bodemmateriaal - organische stof - duingronden - zandgronden - voedingsstoffen - ornamental horticulture - ornamental plants - soil organic matter - organic matter - dune soils - sandy soils - nutrients
Updating soil information with digital soil mapping
Kempen, B. - \ 2011
University. Promotor(en): Tom Veldkamp, co-promotor(en): Gerard Heuvelink; Dick Brus. - [S.l.] : S.n. - ISBN 9789461730909 - 218
bodem - cartografie - kaarten - informatiesystemen - bodemkarteringen - organisch bodemmateriaal - nederland - soil - mapping - maps - information systems - soil surveys - soil organic matter - netherlands
De Bodemkaart van Nederland, schaal 1:50.000, is de belangrijkste bron van bodeminformatie in Nederland. Deze kaart raakt echter in gebieden met veengronden verouderd. Door intensief gebruik van deze gronden verdwijnt het veen. Actualisatie van de bodemkaart is daarom noodzakelijk. Bas Kempen promoveerde op zijn onderzoek hiernaar.
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