Optimal organic carbon values for soil structure quality of arable soils. Does clay content matter?

Soil organic carbon (SOC) is a key indicator of soil health, however, guideline values which indicate degradation and good status have been difficult to define. For soils in England and Wales, indicative management ranges were developed using ranges of SOC from the National Soil Inventory of England and Wales (NSI) for precipitation and clay content classes (Verheijen et al., 2005). Soils with higher clay content are often expected to have higher SOC content and this was evident in the management ranges. SOC interacts with clay particles through surface interactions and this, alongside occlusion in aggregates, is suggested to help protect SOC from decomposition and loss (Dungait et al., 2012). The management ranges, however, lacked a mechanistic perspective such that these might not be optimal ranges for soil physical properties and soil structure.We have used the NSI to investigate how thresholds of clay/SOC might be used to assess SOC status. A clay/SOC ratio of 10 was proposed as a clay-SOC association capacity derived from correlations with soil physical properties (Dexter et al., 2008) and a further two thresholds (clay/SOC = 8 and 13) were proposed to indicate very good and degraded soil structural quality alongside the original threshold (Johannes et al., 2017). Comparing the distribution of soils under different land uses with the clay/SOC threshold ranges gave an increasing quality trend of arable << ley grassland < permanent grassland &#8776; forest. The results suggested that 37% of arable soils would be considered degraded compared with 6% for grassland soils.We have used the thresholds to define an index on a scale where negative values indicate degraded soils, and positive values (up to 1) suggest increasing quality beyond which a soil is considered very good. Data from the Woburn ley-arable rotation experiment (Johnston et al., 2017) have also been evaluated with this index to see how the index value might change with time under different managements. As a quantitative metric for SOC, this could form a monitoring framework and feed into other soil health schemes to assess a soil with respect to a clay-interaction capacity and expected soil quality.&#160;ReferencesDexter et al. (2008). Complexed organic matter controls soil physical properties. Geoderma, 144(3&#8211;4), 620&#8211;627.Dungait et al. (2012). Soil organic matter turnover is governed by accessibility not recalcitrance. Global Change Biology, 18, 1781&#8211;1796.Johannes et al. (2017). Optimal organic carbon values for soil structure quality of arable soils. Does clay content matter? Geoderma, 302, 111.Johnston et al. (2017). Changes in soil organic matter over 70 years in continuous arable and ley-arable rotations on a sandy loam soil in England. European Journal of Soil Science, 68, 305-316.Verheijen et el. (2005). Organic carbon ranges in arable soils of England and Wales. Soil Use and Management, 21, 2&#8211;9.

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Soil structure dynamics in seedbeds: Effects of soil texture and organic carbon content

10.5194/egusphere-egu2020-21373 ◽

2020 ◽

Author(s):

Mats Larsbo ◽

Nargish Parvin ◽

Maria Sandin

Keyword(s):

Organic Carbon ◽

Soil Texture ◽

Soil Structure ◽

Clay Content ◽

Transport Processes ◽

Image Resolution ◽

Strong Positive Correlation ◽

Pressure Potential ◽

Final State ◽

Pore Size Distributions

The soil structure near the surface of agricultural soils changes with seasons mainly by land management together with climatic and biological factors. Quantitative analysis of post-tillage changes in soil structure and related hydraulic properties are necessary for evaluating and improving models of soil hydrological and transport processes. The objectives of this study were to quantify changes in soil seedbed structure induced by rainfall and drainage and to estimate the e&#64256;ects of soil texture and SOC on these changes. We collected samples from the harrowed layer of twenty-six &#64257;ne to coarse textured Swedish mineral soils. Air-dried soil was placed in cylinders (5 cm high, diameter 5 cm) and exposed to simulated rainfall (5 mm h&#8722;1 for 4 h) and drainage (-50 cm pressure potential) cycles in the laboratory. We used X-ray tomography to quantify changes in pore networks in a thin surface layer and in the whole cylinder. Infiltration rates at -5 cm pressure potential were measured using a mini disc tension infiltrometer on replicate air-dried samples and on the samples included in the consolidation experiments at the final state. Total imaged specific pore volumes generally decreased from initial to final state and pore size distributions were shifted towards larger proportions of below image resolution pores (< 80 &#956;m). There was a strong positive correlation between clay content and changes in the specific volume of pores<80 &#956;m. Soils with high clay content and soil organic carbon (SOC) content often have strong aggregates that resist change. Nevertheless, both clay and SOC contents were negatively correlated with the changes in specific imaged pore volume. These results highlight the importance of swelling, which is largely controlled by clay content, for seedbed consolidation. In line with previous studies, when excluding coarse textured soil, the changes in surface porosity were negatively correlated with silt content. Changes in infiltration capacity were not significantly correlated to any basic soil properties. Our results suggest that shrinking-swelling should be a central part in any model for seedbed consolidation.

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SOIL DENSITY AND OPTIMUM MOISTURE FOR SOIL COMPACTION IN FIVE SOIL CLASSES IN WESTERN BAHIA STATE

Revista Engenharia na Agricultura - REVENG ◽

10.13083/reveng.v28i.8005 ◽

2020 ◽

Vol 28 ◽

pp. 211-222

Author(s):

Gustavo Tenório Araújo ◽

Joaquim Pedro Soares Neto ◽

Heliab Bomfim Nunes

Keyword(s):

Regression Analysis ◽

Organic Carbon ◽

Principal Components ◽

Soil Compaction ◽

Soil Structure ◽

Clay Content ◽

Native Forest ◽

Sand Content ◽

Soil Density ◽

Natural Ecosystems

The transformation of natural ecosystems into agricultural environments modifies the soil structure and it may result in its compaction. Therefore, the objective of this work was to determine the optimum moisture for soil compaction (wot) and maximum soil compaction density (Dsmax) in different soil classes in western Bahia State. The samples were collected in five sites covering different soil classes: Orthic Quartzarenic Neosol (RQ), Orthic Ebanic Vertisol (VEo), Haplic Cambisol (CX) and two Red-Yellow Latosol, one already cropped (LVA) and another with native forest (LVA1). Wot and Dsmax were determined according to ABNT NBR 7182 (1986) standards. Data were submitted to a regression analysis and also to the analysis of the principal components (PCA). Wot presented a decreasing order: VEo> LVA> LVA1> CX> RQo, ranging between 8.20 and 15.00% and Dsmax showed the following order RQo> LVA> LVA1> CX> VE, ranging between 1.34 and 1,92 Mg.m-3. The wot was directly proportional to the clay content and the organic carbon and inversely proportional to the soil sand content. For Dsmax, the influence of the clay was inversely proportional whereas in wot, this variable promoted the growth.

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Kualitas Struktur Tanah di Setiap Bentuklahan di DAS Kaliwungu

Majalah Geografi Indonesia ◽

10.22146/mgi.32730 ◽

2020 ◽

Vol 33 (2) ◽

Author(s):

Adhera Sukmawijaya ◽

Junun Sartohadi

Keyword(s):

Unmanned Aerial Vehicle ◽

Soil Profile ◽

Soil Structure ◽

Soil Layer ◽

Soil Management ◽

Visual Evaluation ◽

Structure Quality ◽

Sustainable Soil Management ◽

Aerial Vehicle

Pengelolaan tanah untuk pertanian yang berkelanjutan perlu untuk memeperhatikan 2 hal, yaitu bentuklahan dan tanah. Faktor tanah yang perlu diperhatikan adalah struktur tanah. Penelitian yang fokus pada bentuklahan, struktur tanah, dan implikasinya pada pengelolan belum pernah dilakukan di DAS Kaliwungu. Penelitian bertujuan untuk menganalisis struktur tanah pada setiap bentuklahan sebagai dasar untuk pengelolaan tanah yang berkelanjutan. Kualitas struktur tanah ditentukan dari observasi profil tanah pada setiap bentuklahan. Identifikasi bentuklahan dilakukan berdasarkan pengumpulan data dari Kendaraan Nirawak. Viusal Evaluation of Subsoil Strucutre (SubVESS) digunakan untuk menentukan kualitas struktur tanah berdasarkan karakteristik struktur tanah. Hasil menunjukkan bahwa area penelitian memiliki kualitas struktur tanah yang baik dengan mayoritas nilai kualitas strutktur tanah yang berkisan antara Ssq 1-3. Tidak diperlukan adanya perubahan dalam pengelolaan tanah pada area kajian.Soil management for sustainable agriculture needs to focus on 2 things, which are landform and soil. Soil factor that needs to be focused on is soil structure. The study that focused on landform, soil structure and its implication on soil management has never been done in Kaliwungu Watershed. This research aims to analyze soil structure on every landform as the basis to determine sustainable soil management. Soil structure quality was determine by soil profile observation on every landform. Unmanned Aerial Vehicle (UAV) photographic data was used to identify each landform. Visual Evaluation of Subsoil Structure (SubVESS) was used to identify the quality of soil structure based on its characteristic. The result shows that study area has a good soil structure quality with the majority of soil layer has a good soil structure quality (Ssq 1-3). There is no need to change in soil management is needed.

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Friability and its relationship with clay and organic carbon in soils cultivated with sugar cane

Agronomía Colombiana ◽

10.15446/agron.colomb.v33n3.54068 ◽

2015 ◽

Vol 33 (3) ◽

pp. 365-372

Author(s):

Edgar Alvaro Avila P. ◽

Fabio Rodrigo Leiva ◽

Raúl Madriñán M.

Keyword(s):

Organic Carbon ◽

Sugar Cane ◽

Soil Aggregates ◽

Fine Fraction ◽

Clay Content ◽

Structural Condition ◽

Physical Quality ◽

Moderate Energy ◽

Southwest Region

Friability is a property related to the brittle fracture of soil aggregates and, therefore, is considered a key to the physical quality of soils and the consumption of energy during farming. This paper contains the preliminary results of research that aimed to quantitatively determine the friability index (FI) and its relationship with other soil properties; in particular, this research focused on the relationship between the FI and the clay content and organic carbon percentage (OC) of soils with a different dominance in the fine fraction (1:1 and 2:1 clay) that were cultivated with sugar cane in the southwest region of Colombia. The FI was determined by the compressive strength method using aggregates with diameters between 9.5 and 19.0 mm taken from the surface horizon, which were air air-dried and then dried at a low-temperature in an oven. The clay type content and OC content were determined in these samples. A 98.6% of the studied samples had FI values between 0.24 and 0.80, thus, classifying them as friable (especially those having a 1:1 type clay dominance) and very friable (especially those having a 2:1 type clay dominance), suggesting a structural condition of low to moderate energy requirements for farming, low greenhouse gas emissions (GHG) and a reduced risk of damage on the physical quality if a suitable soil moisture content exists during the tilling. This study found correlations between the texture, OC, and FI of the soils, indicating that the two first properties affected the friability. However, this effect depended on the clay dominance type.

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Exports and inputs of organic carbon on agricultural soils in Germany

Nutrient Cycling in Agroecosystems ◽

10.1007/s10705-020-10087-5 ◽

2020 ◽

Vol 118 (3) ◽

pp. 249-271 ◽

Cited By ~ 1

Author(s):

Anna Jacobs ◽

Christopher Poeplau ◽

Christian Weiser ◽

Andrea Fahrion-Nitschke ◽

Axel Don

Keyword(s):

Organic Carbon ◽

Cover Crops ◽

Agricultural Soils ◽

Net Primary Production ◽

Climate Mitigation ◽

Arable Soils ◽

Grassland Soils ◽

Soil C ◽

Annual Total

AbstractThe quantity and quality of organic carbon (Corg) input drive soil Corg stocks and thus fertility and climate mitigation potential of soils. To estimate fluxes of Corg as net primary production (NPP), exports, and inputs on German arable and grassland soils, we used field management data surveyed within the Agricultural Soil Inventory (n = 27.404 cases of sites multiplied by years). Further, we refined the concept of yield-based Corg allocation coefficients and delivered a new regionalized method applicable for agricultural soils in Central Europe. Mean total NPP calculated for arable and grassland soils was 6.9 ± 2.3 and 5.9 ± 2.9 Mg Corg ha−1 yr−1, respectively, of which approximately half was exported. On average, total Corg input calculated did not differ between arable (3.7 ± 1.8 Mg ha−1 yr−1) and grassland soils (3.7 ± 1.3 Mg ha−1 yr−1) but Corg sources were different: Grasslands received 1.4 times more Corg from root material than arable soils and we suggest that this difference in quality rather than quantity drives differences in soil Corg stocks between land use systems. On arable soils, side products were exported in 43% of the site * years. Cover crops were cultivated in 11% of site * years and contributed on average 3% of the mean annual total NPP. Across arable crops, total NPP drove Corg input (R2 = 0.47) stronger than organic fertilization (R2 = 0.11). Thus, maximizing plant growth enhances Corg input to soil. Our results are reliable estimates of management related Corg fluxes on agricultural soils in Germany.

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Organic carbon sequestration potential, rate and associated practices, as observed in Swiss arable land

10.5194/egusphere-egu2020-19490 ◽

2020 ◽

Author(s):

Pascal Boivin ◽

Xavier Dupla ◽

Ophélie Sauzet ◽

Karine Gondret

Keyword(s):

Organic Carbon ◽

Cover Crops ◽

Soil Structure ◽

Cropping Systems ◽

Arable Land ◽

Conservation Agriculture ◽

Arable Soils ◽

Change Rate ◽

The Past ◽

Sequestration Potential

Since 1993, analysing the soil of any cropped field at least every ten years is required to receive subsides associated with ecological services in Switzerland. After data quality control, we used 3&#8217;000 repeated analyses available from the cantons of Vaud and Geneva to quantify the deficit in Soil Organic Carbon (SOC), the SOC content change rate per year and its time evolution along the past 25 years. We then interviewed 120 farmers on a sample representative of the overall range of SOC change rates to analyse the relationships between their practices in the past ten years and the resulting rate.The SOC deficit was quantified based on the soil vulnerability index, namely SOC to clay ratio (Fell et al., 2018; Johannes et al., 2017), with the 10% SOC:clay ratio as minimum desired SOC level. This yielded different deficits ranging from 20% to 70 % of the average SOC content in the Swiss cantons depending on the cropping systems and the soil types.&#160;Though the SOC deficit was different between the cantons, the distribution of SOC change rates was very similar, ranging from -50&#8240; to +50&#8240; with a median value close to 0. The average change rate, however, was significantly and linearly changing with time, from -4&#8240; in the 1995-2000 period to 9&#8240; in the present. This pattern was identical on both cantons and can be related to the introduction of different mandatory measures in 1993-1998 such as cover crops in fall, and a minimum of 4 crops in the rotation, and the development of conservation agriculture practices.The detailed analysis of cropping practices and related SOC change rates allowed revealing the major options allowing for rapid sequestration and conversely. Moreover, exceptions to the general trends, allowing either to compensate SOC losses practices or jeopardizing sequestration efforts, were also highlighted. Two performing cropping systems were emerging: polyculture with breeding and conservation agriculture. Farmers&#8217; income per ha of these systems were equal to or larger than the conventional models. Interestingly, the first factor for high sequestration performance was diversified rotation and intensive cover crops, regardless of the manuring level. These results were used to define the agricultural sections of the climate plan of the cantons.&#160;Fell, V., Matter, A., Keller, T., Boivin, P., 2018. Patterns and Factors of Soil Structure Recovery as Revealed From a Tillage and Cover-Crop Experiment in a Compacted Orchard. Front. Environ. Sci. 6. https://doi.org/10.3389/fenvs.2018.00134Johannes, A., Matter, A., Schulin, R., Weisskopf, P., Baveye, P.C., Boivin, P., 2017. Optimal organic carbon values for soil structure quality of arable soils. Does clay content matter? Geoderma 302, 14&#8211;21. https://doi.org/10.1016/j.geoderma.2017.04.021

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Hydro-geochemical properties with respect to landuse in the southernmost river of Kerala

Journal of Traditional and Folk Practices ◽

10.25173/jtfp.2018.6.1.94 ◽

2018 ◽

Vol 6 (1) ◽

Author(s):

Badusha M. ◽

Santhosh S

Keyword(s):

Organic Carbon ◽

Drainage Basin ◽

Anthropogenic Activities ◽

Oxygen Demand ◽

Ion Concentration ◽

Total Hardness ◽

Hydrogen Ion Concentration ◽

Geochemical Properties ◽

Quality Of Water

The hydro geochemical features of Neyyar River for a period of one year from May 2015 to April 2016 were analyzed. Six sampling sites were fixed considering physiography and present landuse pattern of the river basin. The residents in the drainage basin are primarily responsible for framing a better landuse and thereby maintain a good water and sediment regime. Geospatial pattern of the present landuse of the study area indicated that the sustainability of this river ecosystem is in danger due to unscientific landuse practices, which is reflected in the river quality as well. The parameters such as hydrogen ion concentration, electrical conductivity, chloride, Biological Oxygen Demand, total hardness and sulphate of river water and Organic Carbon of river bed sediments were analyzed in this study. The overall analysis shows that the highland areas are characterized by better quality of water together with low organic carbon, which is mainly due to better landuse and minimal reclamation. The midland and lowland areas are characterized by poor quality of water with high organic carbon, which is due to high anthropogenic activities and maximum pollutants associated with the region together with the alteration in landuse from a traditional eco-friendly pattern to a severely polluted current pattern.

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Effect of Long-Term Soil Management Practices on Tree Growth, Yield and Soil Biodiversity in a High-Density Olive Agro-Ecosystem

Agronomy ◽

10.3390/agronomy11061036 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1036

Author(s):

Sauro Simoni ◽

Giovanni Caruso ◽

Nadia Vignozzi ◽

Riccardo Gucci ◽

Giuseppe Valboa ◽

...

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Soil Structure ◽

Soil Management ◽

Carbon Pools ◽

Grass Cover ◽

Soil Biodiversity ◽

Canopy Effect ◽

Soil Organic Carbon Pools

Edaphic arthropod communities provide valuable information about the prevailing status of soil quality to improve the functionality and long-term sustainability of soil management. The study aimed at evaluating the effect of plant and grass cover on the functional biodiversity and soil characteristics in a mature olive orchard (Olea europaea L.) managed for ten years by two conservation soil managements: natural grass cover (NC) and conservation tillage (CT). The trees under CT grew and yielded more than those under NC during the period of increasing yields (years 4–7) but not when they reached full production. Soil management did not affect the tree root density. Collecting samples underneath the canopy (UC) and in the inter-row space (IR), the edaphic environment was characterized by soil structure, hydrological properties, the concentration and storage of soil organic carbon pools and the distribution of microarthropod communities. The soil organic carbon pools (total and humified) were negatively affected by minimum tillage in IR, but not UC, without a loss in fruit and oil yield. The assemblages of microarthropods benefited, firstly, from the grass cover, secondly, from the canopy effect, and thirdly, from a soil structure ensuring a high air capacity and water storage. Feeding functional groups—hemiedaphic macrosaprophages, polyphages and predators—resulted in selecting the ecotonal microenvironment between the surface and edaphic habitat.

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