scholarly journals Land use impact on carbon mineralization is mainly caused by variation of particulate organic matter content rather than of soil structure

2021 ◽  
Author(s):  
Steffen Schlüter ◽  
Tim Roussety ◽  
Lena Rohe ◽  
Vusal Guliyev ◽  
Evgenia Blagodatskaya ◽  
...  
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Particulate Organic Matter ◽  
Soil Structure ◽  
Predictive Power ◽  
Carbon Mineralization ◽  
Basal Respiration ◽  
Microstructural Properties ◽  
Soil Functions ◽  
Microbial Hotspots

Abstract. Land use is known to exert a dominant impact on a range of essential soil functions like water retention, carbon sequestration, matter cycling and plant growth. At the same time, land use management is known to have a strong influence on soil structure, e.g. through bioturbation, tillage and compaction. However, it is often unclear whether differences in soil structure are the actual cause for differences in soil functions or just co-occurring. This impact of land use (conventional and organic farming, intensive and extensive meadow, extensive pasture) on the relationship between soil structure and short-term carbon mineralization was investigated at the Global Change Exploratory Facility, in Bad Lauchstädt, Germany. Intact topsoil cores (n = 75) were sampled from each land use type at the early growing season. Soil structure and microbial activity were measured using X-ray computed tomography and respirometry, respectively. Grasslands had a greater microbial activity than croplands, both in terms of basal respiration and rate of carbon mineralization during growth. This was caused by a larger amount of particulate organic matter (POM) in the topsoil of grasslands. The frequently postulated dependency of basal respiration on soil moisture was absent even though some cores were apparently water limited. This finding was related to microenvironments shaping microbial hotspots where the decomposition of plant residues was obviously decoupled from water limitation in bulk soil. Differences in microstructural properties between land uses were surprisingly small, mainly due huge variability induced by patterns of compacted clods and loose areas caused by tillage in cropland soils. The most striking difference was larger macropore diameters in grasslands soil due to the presence of large biopores that are periodically destroyed in croplands. Variability of basal respiration among all soil cores amounted to more than one order of magnitude (0.08–1.42 µg CO2-C h−1 g−1 soil) and was best described by POM mass (R2 = 0.53, p < 0.001). Predictive power was hardly improved by considering all bulk, microstructure and microbial properties jointly. The predictive power of image-derived microstructural properties was low, because aeration was not limiting carbon mineralization and was sustained by pores smaller than the image resolution limit (< 30 µm). The rate of glucose mineralization during growth was explained well by substrate-induced respiration (R2 = 0.84) prior to growth, which was in turn correlated with total microbial biomass, basal respiration and POM mass and again not affected by pore metrics. These findings stress that soil structure had little relevance in predicting carbon mineralization in well-aerated soil, as this predominantly took place in microbial hotspots around degrading POM that was detached from the pore structure and moisture of the bulk soil. Land use therefore affects carbon mineralization in well-aerated soil mainly by the amount and quality of labile carbon.

Impact of land-use on soil structure and soil ecological properties in a long-term field experiment

2021 ◽  
Author(s):  
Steffen Schlüter ◽  
Tim Roussety ◽  
Lena Rohe ◽  
Vusal Guliyev ◽  
Evgenia Blagodatskaya ◽  
...  
Keyword(s):  
Land Use ◽  
Field Experiment ◽  
Soil Properties ◽  
Microbial Activity ◽  
Structural Properties ◽  
Soil Structure ◽  
Basal Respiration ◽  
Soil Functions ◽  
Substrate Induced Respiration ◽  
The Impact

&lt;p&gt;Land use is known to exert a dominant impact on a range of essential soil functions like water retention, carbon sequestration, matter cycling and plant growth. In addition, land use management is known to have a strong influence on soil structure, e.g. through tillage and compaction. While the difference in topsoil structure between grassland and agricultural soil is huge, differences among different farming or grassland management practices can be more subtle. At the same time, soil structure is known to be a suitable indicator for many soil functions. That is, differences in carbon content or plant-available field capacity between different land uses can often be explained by different structural properties.&lt;/p&gt;&lt;p&gt;This impact of land use on the relationship between soil structure and biological indicators for soil processes was explored in the Global Change Exploratory Facility, a well-established (&gt;5 years) field experiment in Bad Lauchst&amp;#228;dt, Germany, comprising five land use types (conventional farming, organic farming, intensive meadow, extensive meadow, extensive pasture). 15 intact topsoil cores were sampled from each land use type in spring 2020 and soil structure and microbial activity were measured using X-ray CT and respirometry, respectively. Microbial activity was estimated by basal respiration at field moisture and by substrate-induced respiration with glucose solution under wet conditions. The aims of this study were to (1) quantify the impact of land use on these structural and biological soil properties and (2) to assess in how far microbial activity can be predicted by the structural properties.&lt;/p&gt;&lt;p&gt;Surprisingly, image-derived macroporosity did not differ between farming and grassland plots mainly due to the huge variability among compacted and non-compacted samples in the farming plots. Other pore metrics like pore distance and pore connectivity followed the same trend, whereas mean pore size was larger in the grassland plots due to more large biopores. Basal respiration increased in the order farming &lt; meadow &lt; pasture, whereas the order was reversed for substrate-induced respiration. The predictability of basal respiration (R&lt;sup&gt;2&lt;/sup&gt;=0.29) and substrate-induced respiration (R&lt;sup&gt;2&lt;/sup&gt;=0.5) with explanatory variables based on pore metrics and bulk soil properties was rather low, with root mass and bulk density being the best predictors.&lt;/p&gt;

Non-living soil organic matter: what do we know about it?

1998 ◽  
Vol 38 (7) ◽  
pp. 667 ◽  
Author(s):  
J. O. Skjemstad ◽  
L. J. Janik ◽  
J. A. Taylor
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Structure ◽  
Chemical Structure ◽  
Review Paper ◽  
Critical Component ◽  
Biological Functions ◽  
Soil Functions ◽  
Mineral Associations ◽  
Considerable Work

Summary. Non-living soil organic matter is a small but critical component of soils contributing to soil structure, fertility and a range of other chemical, physical and biological functions. Although considerable work has contributed to our knowledge of its distribution, chemical structure, mineral associations and turnover, there is still little information on which fractions or pools of non-living soil organic matter are implicated in various soil functions and to what extent. This review paper summarises some of what is known about the distribution, chemistry, mineral associations and soil structure, turnover and the measurement of non-living soil organic matter, with particular emphasis on Australia. It also discusses some of the difficulties in using current methods for describing the function of this material in soil.

Particle-size and organic matter effects on structure and water retention of soils

Biologia ◽  
2015 ◽  
Vol 70 (11) ◽  
Author(s):  
Kálmán Rajkai ◽  
Brigitta Tóth ◽  
Gyöngyi Barna ◽  
Hilda Hernádi ◽  
Mihály Kocsis ◽  
...  
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Soil Structure ◽  
Water Retention ◽  
Sandy Soils ◽  
Soil Profiles ◽  
Matter Effects

AbstractWater storage and flow in soils are highly dependent on soil structure, which strongly determines soil porosity. However pore size distribution can be derived from soil water retention curve (SWRC). Structural characteristics of cultivated arable fields (693 soil profiles, 1773 samples) and soils covered by treated forest stands (137 soil profiles, 405 samples) were selected from the MARTHA Hungarian soil physical database, and evaluated for expressing organic matter effects on soil structure and water retention. For this purpose the normalized pore size distribution curves were determined for the selected soils, plus the modal suction (MS) corresponding to the most frequent pore size class of the soil. Skewness of soils’ pore size distribution curves are found different. The quasi-normal distribution of sandy soils are transformed into distorted in clayey soils. A general growing trend of MS with the ever finer soil texture was shown. Sandy soils have the lowest average MS values, i.e. the highest most frequent equivalent pore diameter. Silty clay and clay soil textures are characterized by the highest MS values. A slight effect of land use and organic matter content is also observable in different MS values of soils under forest vegetation (’forest’) and cultivated arable land (‘plough fields’). MS values of the two land uses were compared statistically. The results of the analyses show that certain soil group’s MS are significantly different under forest vegetation and cultivation. However this difference can be explained only partly and indirectly by the organic matter of different plant coverage in the land use types.

scholarly journals Labile and stable fractions of soil organic matter under management systems and native cerrado

2010 ◽  
Vol 34 (3) ◽  
pp. 907-916 ◽  
Author(s):  
Cícero Célio de Figueiredo ◽  
Dimas Vital Siqueira Resck ◽  
Marco Aurélio Carbone Carneiro
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Particulate Organic Matter ◽  
Block Design ◽  
Management Systems ◽  
Total N ◽  
Organic C ◽  
Randomized Block Design ◽  
Stable Organic Matter

Soil organic matter can be analyzed on the basis of the different fractions. Changes in the levels of organic matter, caused by land use, can be better understood by alterations in the different compartments. The aim of this study was to evaluate the effect of different management systems on the labile and stable organic matter of a dystrophic Red Latosol (Oxisol). The following properties were determined: total organic C and total N (TOC and TN), particulate organic C and particulate N (POC and PN), organic C and N mineral-associated (MOC and NM) and particulate organic C associated with aggregate classes (POCA). Eight treatments were used: seven with soil management systems and one with native Cerrado as a reference. The experiment was designed to study the dynamics of systems of tillage and crop rotation, alternating in time and space. The experimental design was a randomized block design with three replications. The soil samples were collected from five depths: 0-5, 5-10, 10-20, 20-30 and 30-40 cm. Changes in organic C by land use occurred mainly in the fraction of particulate organic matter (> 53 mm). Proper management of grazing promoted increased levels of particulate organic matter by association with larger aggregates (2-8 mm), demonstrating the importance of the formation of this aggregate class for C protection in pasture.

Assessing carbon lability of particulate organic matter from δ13C changes following land-use change from C3 native vegetation to C4 pasture

Soil Research ◽  
2011 ◽  
Vol 49 (1) ◽  
pp. 98 ◽  
Author(s):  
R. C. Dalal ◽  
B. A. Cowie ◽  
D. E. Allen ◽  
S. A. Yo
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Land Use Change ◽  
Particulate Organic Matter ◽  
Soil Types ◽  
Native Vegetation ◽  
Organic C ◽  
Δ13c Values ◽  
Soc Fractions ◽  
Total Organic C

Land-use change from C3 vegetation (δ13C values, –30‰ to –24‰) to C4 vegetation (δ13C values, –14‰ to –11‰) provides a useful quantitative technique for estimating organic C turnover in soil, even when total organic C changes are negligible. We utilised this technique to estimate C turnover in physically fractionated soil organic matter, particulate organic matter C (POM C >250 μm fraction and POM C 250–53 μm fraction), and the <53 μm fraction. There were small changes in total soil organic C (SOC) after 23 years of land-use change from native vegetation (mixed vegetation of Acacia harpophylla and Casuarina cristata) to buffel grass (Cenchrus ciliaris L. cv. Biloela) pasture grown on Vertosol–Dermosol–Sodosol soil types. The SOC values (t/ha) under native vegetation were: 31 ± 3 for the 0–0.1 m depth, 21 ± 1 for the 0.1–0.2 m depth, 15 ± 3 for the 0.2–0.3 m depth, and 16 ± 2 for the 0.3–0.4 m depth; the corresponding SOC values under pasture were 25 ± 2, 19 ± 2, 14 ± 2, and 13 ± 1 t/ha. The respective δ13C values in 0–0.1 m depths of the whole SOC and POM C >250 μm fraction changed from –25.5 ± 0.1‰ and –25.5 ± 0.3‰ under native vegetation to –20.1 ± 0.5‰ and –19.4 ± 0.2‰ under pasture. Similar, although smaller, differences were observed for other depths and SOC fractions. The SOC turnover periods (years) were 31 ± 6 for the 0–0.1 m depth, 60 ± 5 for the 0.1–0.2 m depth, 55 ± 15 for the 0.2–0.3 m depth, and 63 ± 20 for the 0.3–0.4 m depth; the corresponding turnover periods for the POM C >250 μm fraction were 13 ± 2, 19 ± 5, 14 ± 4, and 12 ± 5 years. The turnover periods of SOC in the POM C 250–53 μm and <53 μm fractions were similar to, or longer than, for the whole SOC at all depths studied. Thus, the lability of the SOC and SOC pools was in the order: POM C >250 μm fraction > POM C 53–250 μm fraction = POM C <53 μm fraction = whole SOC.

scholarly journals Using the Methodological Procedures for Water Erosion Risk Areas Identification for Sustainable Land Use

2020 ◽  
Vol 39 (2) ◽  
pp. 145-158
Author(s):  
Viera Petlušová ◽  
Peter Petluš ◽  
Erika Tobiašová ◽  
Juraj Hreško
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Soil Structure ◽  
Water Erosion ◽  
Sustainable Land Use ◽  
Soil Protection ◽  
The European Union ◽  
Erosion Risk ◽  
Risk Areas ◽  
Methodological Procedures

AbstractThe countries of the European Union have joined, inter alia, soil protection in the Common Agricultural Policy (hereinafter referred to as CAP). Accelerated soil erosion is a problem resulting from inappropriate land management, which affects both the presence of organic matter and the soil structure. The tool for elimination of negative impacts on soil can be its sustainable use. This requires the use of an accurate system to improve its condition. The first step should be problem identification and localisation. The research is aimed at the identification of water erosion risk areas by using selected methodological procedures. The research area was located at the intensively used hilly land of the Southwestern Slovakia. The digitisation of the manual interpretation of erosion risk areas with the use of aerial photos, erosion modelling, chemical analysis of soil organic matter (SOM) and analysis of soil structure were used. Verification was implemented via the field research with the use of the soil probes. Methods affirmed significant presence of the water erosion in the area. Efficient identification of erosional processes is possible via combination of presented methods by taking into consideration geological, geomorphological, pedological and geographical conditions and the use of the area over a longer period of time. The results of using methods that ensure accurate and effective localisation of erosion surfaces can be used for sustainable land use and its conservation.

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