Effects of land use on soil microbial biomass, activity and community structure at different soil depths in the Danube floodplain
Leeuwen, J.P. van; Djukic, I. ; Bloem, J. ; Lehtinen, T. ; Hemerik, L. ; Ruiter, P.C. de; Lair, G.J. - \ 2017
European Journal of Soil Biology 79 (2017). - ISSN 1164-5563 - p. 14 - 20.
Land use - Microbial activity - PLFA - Soil depth - Soil ecosystem functioning - Soil microbial biomass
Human activities such as land use and -management may strongly affect the soil's ability to provide ecosystem services, in which microbes are playing a key role. Because sampling is usually restricted to the topsoil, little is known about effects of land use on ecosystem functioning down the soil profile. The present study assessed the effects of different land use types (arable, forest, grassland) on soil microbial biomass, activity and community structure at different soil depths (A, AC, C horizons), under the same climatic and pedological conditions, in the Danube Floodplain in Austria. Microbial biomass was 4–5 times lower in the arable field than in forest and grassland in the upper horizons. Additionally, both microbial biomass and activity decreased 3–4 fold with soil depth in forest and grassland. However, up to 30% of total microbial biomass was found in the C horizon in the arable field. We found a differentiation of microbial community structure between land use types and with soil depth: i.e. strong differences in the topsoil between land uses, whereas community structure in the C horizon was similar. This study confirms that land use exerts strong effects on soil microbes in the topsoil and that microbial biomass and activity decrease with soil depth. However, considerable microbial biomass and activity are found below 30 cm depth which is usually not included in samplings. In the deeper soil horizon effects of land use disappear, with microbial community structure and functioning becoming similar in similar pedological conditions.
The elusive role of soil quality in nutrient cycling: a review
Schroder, Jaap ; Schulte, R.P.O. ; Creamer, R.E. ; Delgado, A. ; Leeuwen, J. Van; Lehtinen, T. ; Rutgers, M. ; Spiegel, H. ; Staes, J. ; Tóth, G. ; Wall, D.P. - \ 2016
Soil Use and Management 32 (2016)4. - ISSN 0266-0032 - p. 476 - 486.
Cycling of nutrients, including nitrogen and phosphorus, is one of the ecosystem services we expect agricultural soils to deliver. Nutrient cycling incorporates the reuse of agricultural, industrial and municipal organic residues that, misleadingly, are often referred to as ‘wastes’. The present review disentangles the processes underlying the cycling of nutrients to better understand which soil properties determine the performance of that function. Four processes are identified (i) the capacity to receive nutrients, (ii) the capacity to make and keep nutrients available to crops, (iii) the capacity to support the uptake of nutrients by crops and (iv) the capacity to support their successful removal in harvested crop. Soil properties matter but it is imperative that, as constituents of ‘soil quality’, they should be evaluated in the context of management options and climate and not as ends in their own right. The effect of a soil property may vary depending on the prevailing climatic and hydrologic conditions and on other soil properties. We recognize that individual soil properties may be enhancing one of the processes underlying the cycling of nutrients but simultaneously weakening others. Competing demands on soil properties are even more obvious when considering other soil functions such as primary production, purification and flow regulation of water, climate modification and habitat provision, as shown by examples. Consequently, evaluations of soil properties and management actions need to be site-specific, taking account of local aspects of their suitability and potential challenges
Aggregation and organic matter in subarctic Andosols under different grassland management
Lehtinen, T. ; Gisladottir, G. ; Lair, G.J. ; Leeuwen, J.P. van; Blum, W.E.H. ; Bloem, J. ; Steffens, M. ; Ragnarsdottir, K.V. - \ 2015
Acta Agriculturae Scandinavica Section B-Soil and Plant Science 65 (2015)3. - ISSN 0906-4710 - p. 246 - 263.
c-13 nmr-spectroscopy - soil microbial biomass - mediterranean conditions - structural stability - cultivated soils - farming systems - volcanic soils - carbon stocks - land-use - tillage
Quantity and quality of soil organic matter (SOM) affect physical, chemical, and biological soil properties, and are pivotal to productive and healthy grasslands. Thus, we analyzed the distribution of soil aggregates and assessed quality, quantity, and distribution of SOM in two unimproved and improved (two organic and two conventional) grasslands in subarctic Iceland, in Haplic and Histic Andosols. We also evaluated principal physicochemical and biological soil properties, which influence soil aggregation and SOM dynamics. Macroaggregates (>250 µm) in topsoils were most prominent in unimproved (62–77%) and organically (58–69%) managed sites, whereas 20–250 µm aggregates were the most prominent in conventionally managed sites (51–53%). Macroaggregate stability in topsoils, measured as mean weight diameter, was approximately twice as high in organically managed (12–20 mm) compared with the conventionally managed (5–8 mm) sites, possibly due to higher organic inputs (e.g., manure, compost, and cattle urine). In unimproved grasslands and one organic site, macroaggregates contributed between 40% and 70% of soil organic carbon (SOC) and nitrogen to bulk soil, whereas in high SOM concentration sites free particulate organic matter contributed up to 70% of the SOC and nitrogen to bulk soil. Aggregate hierarchy in Haplic Andosols was confirmed by different stabilizing mechanisms of micro- and macroaggregates, however, somewhat diminished by oxides (pyrophosphate-, oxalate-, and dithionite-extractable Fe, Al, and Mn) acting as binding agents for macroaggregates. In Histic Andosols, no aggregate hierarchy was observed. The higher macroaggregate stability in organic farming practice compared with conventional farming is of interest due to the importance of macroaggregates in protecting SOM and soils from erosion, which is a prerequisite for soil functions in grasslands that are envisaged for food production in the future.
An ecosystem approach to assess soil quality in organically and conventionally managed farms in Iceland and Austria
Leeuwen, J.P. van; Lehtinen, T. ; Lair, G.J. ; Bloem, J. ; Hemerik, L. ; Ragnarsdóttir, K.V. ; Gísladóttir, G. ; Newton, J.S. ; Ruiter, P.C. de - \ 2015
SOIL 1 (2015). - ISSN 2199-3971 - p. 83 - 101.
Intensive agricultural production can be an important driver for the loss of long-term soil quality. For this reason, the European Critical Zone Observatory (CZO) network adopted four pairs of agricultural CZO sites that differ in their management: conventional or organic. The CZO sites include two pairs of grassland farms in Iceland and two pairs of arable farms in Austria. Conventional fields differed from the organic fields in the use of artificial fertilisers and pesticides. Soils of these eight farms were analysed in terms of their physical, chemical, and biological properties, including soil aggregate size distribution, soil organic matter contents, abundance of soil microbes and soil fauna, and taxonomic diversity of soil microarthropods. In Icelandic grasslands, organically farmed soils had larger mean weight diameters of soil aggregates than the conventional farms, while there were no differences on the Austrian farms. Organic farming did not systematically influence organic matter contents or composition, nor soil carbon and nitrogen contents. Also, soil food web structures, in terms of presence of trophic groups of soil organisms, were highly similar among all farms, indicating a low sensitivity of trophic structure to land use or climate. However, soil organism biomass, especially of bacteria and nematodes, was consistently higher on organic farms than on conventional farms. Within the microarthropods, taxonomic diversity was systematically higher in the organic farms compared to the conventional farms. This difference was found across countries and farm, crop, and soil types. The results do not show systematic differences in physical and chemical properties between organic and conventional farms, but confirm that organic farming can enhance soil biomass and that microarthropod diversity is a sensitive and consistent indicator for land management.
|soil food web structure and faunal diversity in organic farming versus conventional farming
Bloem, J. ; Leeuwen, J.P. van; Lehtinen, T. ; Lair, G.J. ; Hemerik, L. - \ 2014
|soil ecosystem development in a glacial chronosequence in iceland
Bloem, J. ; Leeuwen, J.P. van; Lehtinen, T. ; Gisladottir, G. ; Ragnarsdottir, K.V. - \ 2014
Do aggregate stability and soil organic matter content increase following organic inputs?
Bloem, J. ; Lehtinen, T. ; Gisladottir, G. ; Leeuwen, J.P. van; Steffens, M. - \ 2014
Agriculture is facing several challenges such as loss of soil organic matter (SOM); thus, sustainable farming management practices are needed. Organic farming is growing as an alternative to conventional farming; in Iceland approximately 1% and in Austria 16% of utilized agricultural area is under organic farming practice. We analyzed the effect of different farming practices (organic, and conventional) on soil physicochemical and microbiological properties in grassland soils in Iceland and cropland soils in Austria. Organic farms differed from conventional farms by absence of chemical fertilizers and pesticide use. At these farms, we investigated soil physicochemical (e.g. soil texture, pH, CAL-extractable P and K) and microbiological properties (fungal and bacterial biomass and activity). The effects of farming practices on soil macroaggregate stability and SOM quantity, quality and distribution between different fractions were studied following a density fractionation. In Iceland, we sampled six grassland sites on Brown (BA) and Histic (HA) Andosols; two sites on extensively managed grasslands, two sites under organic and two sites under conventional farming practice. In Austria, we sampled four cropland sites on Haplic Chernozems; two sites under organic and two sites under conventional farming practice. We found significantly higher macroaggregate stability in the organic compared to the conventional grasslands in Iceland. In contrast, slightly higher macroaggregation in conventional compared to the organic farming practice was found in croplands in Austria, although the difference was not significant. Macroaggregates were positively correlated with fungal biomass in Iceland, and with Feo and fungal activity in Austria. In Austria, SOM content and nutrient status (except for lower CAL-extractable P at one site) were similar between organic and conventional farms. Our results show that the organic inputs may have enhanced macroaggregation in organic farming practice compared to conventional in the permanent grassland soils in Iceland but were only enough to maintain the SOM content and macroaggregation in the cropland soils in Austria.
|Farming effects on soil organic matter and aggregate stability of Icelandic Brown and Histic Andosols
Lehtinen, T. ; Gisladottir, G. ; Lair, G.J. ; Leeuwen, J. van; Blum, W.E.H. ; Bloem, J. ; Ragnarsdottir, K.V. - \ 2013
In: Proceedings of the Soil Carbon Sequestration for climate, food security and ecosystem services, May 26-29, 2013, Reykjavik, Iceland. - Reykjavik : Soil Conservation Service of Iceland & Agricultural University of Iceland - p. 32 - 32.
Results of an Interdisciplinary Research Project on Soil Aggregate Formation in CZO's
Regelink, I.C. ; Lair, G.J. ; Lehtinen, T. ; Leeuwen, J. van; Zaan, B.M. van der; Schiefer, J. ; Rousseva, S. ; Blaud, A. ; Mennon, M. ; Banwart, S. - \ 2013
In: Proceedings of Goldschmidt 2013, August 25-30, 2013, Florence Italy. - Geochemical Society/GeoScienceWorld - p. 2038 - 2038.
Soil physical properties such as aggregate stability and porosity are crucial for the soil’s agricultural productivy, carbon sequestration capacity and water holding capacity. The formation of soil aggregates is the result of complex interactions between biological, chemical and physical soil processes. Therefore, multi-disciplinary research on Critical Zone Observatories (CZO’s) is needed to unravel the keyfactors controlling aggregate formation . We will discuss the role of soil chemical and biological processes in the formation of soil aggregates. These data are the result of the joined efforts from soil chemists and biologist collaborating within the SoilTrEC project . We show that organic-mineral interactions and solution chemistry are important for formation of primary soil aggregates. Especially Fe-(hydr)oxides play a crucial role because of their strong interactions with organic substances in the soil . Macroaggregates are formed when both organic matter, clay minerals and Fe-(hydr)oxides are present in sufficient amounts. These soil macro-aggregates act as habitats for micro-organisms which may in turn alter the organic substances within the soil aggregates. The microbial communitities within the macro-aggregates are affected by the land use. Furthermore, land use shows pronounced effects on the structure of the pores within the soil macro-aggregates. Overall, we want to highlight the importance of multidisciplinary research in understanding the complex interactions between chemical and biological processes within the critical zone.
Response of soil properties to different farming practices - case studies in Iceland and Austria
Lehtinen, T. ; Lair, G.J. ; Gisladottir, G. ; Bloem, J. ; Leeuwen, J. van; Ragnarsdottir, K.V. ; Blum, W. - \ 2012
In: Proceedings of the 4th International Congress EUROSOIL, July 2-6, 2012, Bari, Italy. - European Confederation of Soil Science Societies - p. 2661 - 2661.
Arable land covers approximately one fourth of the global land area, but only half of it can be used efficiently for cultivation to feed the growing population. Modern agriculture has developed highly productive food and biomass-producing systems based on industrial principles, which has lead to a considerable environmental burden. Organic agriculture has expanded as a movement towards more sustainable food production, which aims to maintain the key functions and ecosystems services of soils. At present, approximately 0.7% of global and 4% of European agricultural lands are managed organically (Willer and Youssefi, 2007). Soil organic matter (SOM) and its turnover play a pivotal role in the biogeochemical cycling of nutrients and in the response of terrestrial carbon to future climate scenarios. Its fate and dynamics are mainly governed and understood by its properties and physiology of the soil organisms (von Lützow and Kögel-Knabler, 2009). A key to understand and define a sustainable agricultural soil system is to quantify the impact of different land use on soil structure and biogeochemistry, with emphasis on nutrient turnover. The goal of our future research is to evaluate SOM pools in different soil aggregate sizes under different farming systems (organic vs. conventional) and link them to soil biodiversity. Soils were selected along cultivation age gradients under subarctic (Iceland, Andosols) and continental climate (Austria, Chernozems). The further outcome of this research is to identify quantifiable natural indicators for farm sustainability assessments. Gained data will also be linked to energy balance and food productivity in order to get more insights in benefits of different farming practices.
|Impact of time and land use on carbon accumulation and structure formation in soils
Lair, G.J. ; Lehtinen, T. ; Djukic, I. ; Schiefer, J. ; Bloem, J. ; Blum, W. - \ 2012
In: Proceedings of the 4th International Congress EUROSOIL, July 2-16, 2012, Bari, Italy. - European Confederation of Soil Science Societies - p. 778 - 778.