The contribution of biogenic organic matter to aggregation in soil - a review

2021 ◽  
Author(s):  
Tom Guhra ◽  
Katharina Stolze ◽  
Kai Uwe Totsche
Keyword(s):  
Organic Matter ◽  
Extracellular Polymeric Substances ◽  
Soil Aggregates ◽  
Aggregate Stability ◽  
Close Approach ◽  
Small Scale ◽  
Soil Organisms ◽  
Field Scale ◽  
Formation Pathway

<p>Soil organisms (plants, invertebrates, and microorganisms) are involved in soil structuring and are key factors of aggregation through bioturbation, organic matter (OM) decomposition, and secretion of biogenic OM (e.g., root exudates, mucus and extracellular polymeric substances). At the field scale, soil quality, functions, as well as nutrient cycling usually benefit from the activity of soil organisms that frequently cause substantial changes to soil properties by the formation of aggregates. The biogenic formation pathway of soil aggregates reflects a cascade of small-scale sub-processes (e.g., OM supply, OM adsorption, organo-mineral association formation, their transport, immobilization, and involvement into aggregate structure) that are often portrayed solitarily in literature and demand for a comprehensive framework that consistently describes their synergies and dependencies. Particularly, the role of complexly composed biogenic OM as <strong>bridging/aggregation agent</strong> is controversially discussed in literature, as they may promote as well as inhibit aggregation at the same time. This non-uniform behavior is controlled by the complex interplay of milieu parameters (e.g., ionic strength, temperature, pH and redox-potential) and the physicochemical properties of biogenic OM (e.g., protein-to-polysaccharide-ratio, molecular weight of biopolymers, functional groups, and biopolymer structure). Hence, we discuss biogenic OM with respect to the three different roles in aggregation which can be identified from literature: (I) as <strong>bridging agent</strong> which permits the aggregation due to attraction and surface modifications, (II) as <strong>separation agent</strong> which favors the formation, mobility and transport of organo-mineral associations and inhibits their further involvement into aggregates, and (III) as <strong>gluing agent</strong> which mediates aggregate stability, after an external force provokes a close approach of soil particles. In natural systems, OM may take these roles simultaneously and with varying degree across spatiotemporal scales. Considering this for the discussion of the role of biogenic OM in soil aggregate formation, we will achieve a more detailed and interdisciplinary understanding of its pathways into soil aggregates, which can help to draw comprehensive conclusions from lab and field-scale studies, prospectively.</p>

scholarly journals Enzymatic biofilm detachment causes a loss of aggregate stability in a sandy soil

2016 ◽  
Author(s):  
F. Büks ◽  
M. Kaupenjohann
Keyword(s):  
Organic Matter ◽  
Soil Quality ◽  
Extracellular Polymeric Substances ◽  
Soil Aggregates ◽  
Aggregate Stability ◽  
Agricultural Practices ◽  
Enzyme Treatment ◽  
Rooting Depth ◽  
Experimental Proof ◽  
Biofilm Detachment

Abstract. The stability of soil aggregates against shear and compressive forces as well as water caused dispersion is an integral marker of soil quality. High stability results in less soil compactibility and erodibility, enhanced water retention, a dynamic water transport and aeration regime, increased rooting depth and protection of soil organic matter (SOM) against microbial degradation. For decades the importance of biofilm extracellular polymeric substances (EPS) regarding aggregate stability has been canonical because of its distribution, geometric structure and ability to link primary particles. However, experimental proof is still missing. This lack is mainly due to methodological reasons. Thus, the objective of this work is to develop a method of enzymatic biofilm detachment for studying the effects of EPS on soil aggregate stability. The method combines an enzymatic pre-treatment with different activities of α-glucosidase, β-galactosidase, DNAse and lipase, which preserves aggregate structure, with a subsequent sequential ultrasonic treatment for disaggregation and density-fractioning. Soil organic carbon (SOC) releases of treated samples were compared to an enzyme-free control. To test the effectivity of biofilm detachment the ratio of bacterial DNA from sessile and suspended cells after enzymatic treatment was measured by quantitative real-time PCR. Although the enzyme treatment was not sufficient for total biofilm removal, our results confirm, that EPS stabilizes soil aggregates predominantly by a strong intra-aggregate fixation, and enzymatic biofilm digestion caused a shift of occluded particulate organic matter (POM) to more fragile binding patterns. This suggests that an effect of agricultural practices on soil microbial populations could influence aggregate stability and thereby soil quality.

scholarly journals Enzymatic biofilm digestion in soil aggregates facilitates the release of particulate organic matter by sonication

SOIL ◽  
2016 ◽  
Vol 2 (4) ◽  
pp. 499-509 ◽  
Author(s):  
Frederick Büks ◽  
Martin Kaupenjohann
Keyword(s):  
Organic Matter ◽  
Soil Quality ◽  
Particulate Organic Matter ◽  
Extracellular Polymeric Substances ◽  
Soil Aggregates ◽  
Aggregate Stability ◽  
Enzyme Treatment ◽  
Rooting Depth ◽  
Experimental Proof ◽  
Biofilm Detachment

Abstract. The stability of soil aggregates against shearing and compressive forces as well as water-caused dispersion is an integral marker of soil quality. High stability results in less compaction and erosion and has been linked to enhanced water retention, dynamic water transport and aeration regimes, increased rooting depth, and protection of soil organic matter (SOM) against microbial degradation. In turn, particulate organic matter is supposed to support soil aggregate stabilization. For decades the importance of biofilm extracellular polymeric substances (EPSs) regarding particulate organic matter (POM) occlusion and aggregate stability has been canonical because of its distribution, geometric structure and ability to link primary particles. However, experimental proof is still missing. This lack is mainly due to methodological reasons. Thus, the objective of this work is to develop a method of enzymatic biofilm detachment for studying the effects of EPSs on POM occlusion. The method combines an enzymatic pre-treatment with different activities of α-glucosidase, β-galactosidase, DNAse and lipase with a subsequent sequential ultrasonic treatment for disaggregation and density fractionation of soils. POM releases of treated samples were compared to an enzyme-free control. To test the efficacy of biofilm detachment the ratio of bacterial DNA from suspended cells and the remaining biofilm after enzymatic treatment were measured by quantitative real-time PCR. Although the enzyme treatment was not sufficient for total biofilm removal, our results indicate that EPSs may attach POM within soil aggregates. The tendency to additional POM release with increased application of enzymes was attributed to a slight loss in aggregate stability. This suggests that an effect of agricultural practices on soil microbial populations could influence POM occlusion/aggregate stability and thereby carbon cycle/soil quality.

Comparison of aggregate stability within six soil profiles under conventional tillage using various laboratory tests

Biologia ◽  
2009 ◽  
Vol 64 (3) ◽  
Author(s):  
Radka Kodešová ◽  
Marcela Rohošková ◽  
Anna Žigová
Keyword(s):  
Organic Matter ◽  
Soil Aggregates ◽  
Organic Matter Content ◽  
Aggregate Stability ◽  
Clay Content ◽  
Soil Aggregate ◽  
Matter Content ◽  
The Other ◽  
Structure Stability ◽  
Soil Aggregate Stability

AbstractSoil structure stability was studied in every diagnostic horizons of six soil types (Haplic Chernozem, Greyic Phaeozem, two Haplic Luvisols, Haplic Cambisol, Dystric Cambisol) using different techniques investigating various destruction mechanisms of soil aggregates. Soil aggregate stability, assessed by the index of water stable aggregates (WSA), varied depending on the organic matter content, clay content and pHKCl. The presence of clay and organic matter coatings and fillings, and presence of iron oxides in some soils increased stability of soil aggregates. On the other hand periodical tillage apparently decreased aggregate stability in the Ap horizons. Coefficients of aggregate vulnerability resulting from fast wetting (KV 1) and slow wetting (KV 2) tests showed similar trends of the soil aggregate stability as the WSA index, when studied for soils developed on the similar parent material. There was found close correlation between the WSA index and the KV 1 value, which depended also on the organic matter content, clay content and pHKCl. Less significant correlation was obtained between the WSA index and the KV 2 value, which depended on the organic matter content and clay content. Coefficients of vulnerability resulting from the shaking after pre-wetting test (KV 3) showed considerably different trends in comparison to the other tests due to the different factors affecting aggregate stability against the mechanical destruction. The KV 3 value depended mostly on cation exchange capacity, pHKCl and organic matter content.

The rôle of organic matter in soil fertility

1977 ◽  
Vol 281 (980) ◽  
pp. 209-219 ◽  
Keyword(s):  
Organic Matter ◽  
Plant Material ◽  
Farmyard Manure ◽  
Nutrient Status ◽  
Clay Soils ◽  
Organic Carbon Content ◽  
Heterogeneous Mixture ◽  
Soil Organisms ◽  
Grass Ley

Soil organic matter is a very heterogeneous mixture of substances, ranging from plant and root fragments, through the living bodies of the soil organisms, to brown amorphous humic substances produced by their activity. These materials have very different rates of decomposition in the soil and very different effects on the soil tilth and nutrient status. The method of soil cultivation used affects the stabilizing power of a limited addition of plant material. The soil organic carbon content under a well fertilized arable rotation stabilizes at about 1 % on many loam and clay soils. Incorporating a 1 year ley in the rotation or ploughing in all the straw produced may increase this by just under 0.1 %, and using normal farm dressings of farmyard manure by just over 0.1 %. These increases may be additive, but the increases are considerably smaller than this on some soils. Incorporating a 3 year grass ley in a 5 or 6 course rotation increases the carbon by between 0.15 and 0.3%, and there is some evidence that farmyard manure has a greater effect if used in a ley-arable than an all-arable rotation. A 3 year lucerne ley behaves more like a 1 year grass-clover ley except just after it has been ploughed out, though it increases the nitrifiable nitrogen in the soil for several years.

scholarly journals A Mathematical Approach to Evaluating the Influence of Various Factors on the Stability of Aggregates in Vertisols

1969 ◽  
Vol 53 (1) ◽  
pp. 57-60
Author(s):  
M. A. Lugo López ◽  
Raúl Pérez Escolar
Keyword(s):  
Organic Matter ◽  
Soil Aggregates ◽  
Aggregate Stability ◽  
Correlation Coefficients ◽  
Clay Content ◽  
Mathematical Approach ◽  
Single Factor ◽  
Additional Increase ◽  
Independent Variable ◽  
The Stability

A mathematical approach is presented in this paper to evaluate the influence of such factors as clay content, silt content, organic matter, Ca + Mg, and soluble sodium upon the stability of soil aggregates in a group of Vertisols from the Lajas Valley, P.R. The relationships between aggregate stability and silt and clay were not significant. When the percentage of organic matter was considered as the independent variable, a highly significant correlation coefficient of 0.66 was obtained. Therefore, almost 43 percent of the variability in aggregate stability could be explained on the basis of this single factor. Attempts to increase the percentage of the variability which could be explained in terms of the content of Ca + Mg, and also of soluble sodium, yielded correlation coefficients of 0.70 and 0.74, respectively. Thus, only a slight, but significant, additional increase could be explained when these variables were included.

Perbaikan Stabilitas Agregat Tanah Pasir Berlempung Menggunakan Bakteri Pemantap Agregat dan Bahan Organik

2020 ◽  
Vol 42 (2) ◽  
pp. 161
Author(s):  
Diana Utama ◽  
Nuni Gofar ◽  
Adipati Napoleon
Keyword(s):  
Organic Matter ◽  
Incubation Period ◽  
Soil Aggregates ◽  
Aggregate Stability ◽  
Soil Aggregation ◽  
Cattle Manure ◽  
Loamy Sand ◽  
Sand Soil ◽  
Loamy Sand Soil ◽  
Observation Period

<p class="teksabst"><strong>Abstrak.</strong><em> </em>Penelitian ini bertujuan untuk menganalisis stabilitas agregat tanah dengan perlakuan berbagai isolat bakteri pemantap agregat (BPA) dan bahan organik berupa kompos yang terbuat dari campuran 90% rumput <em>Cyperus pilosus</em> Vahl dan 10% kotoran sapi, dengan masa inkubasi yang berbeda. Taraf perlakuan terdiri dari kontrol, kombinasi isolat I, II, dan III masing – masing dikombinasikan dengan komposisi bahan organik 0%, 0.5%, dan 1%. Hasil penelitian ini menunjukkan aplikasi isolat BPA pada tanah pasir berlempung disertai pemberian bahan organik menyebabkan populasi yang lebih tinggi dibandingkan tanpa aplikasi keduanya. <em>Klebsiella </em>sp. LW-13 yang dikombinasi dengan 1% bahan organik dan <em>Bukholderia anthina </em>MYSP113 yang dikombinasi dengan berbagai taraf bahan organik (0 hingga 1%) menyebabkan agregat menjadi sangat mantap sekali pada pengamatan 60 hari setelah aplikasi. Eksopolisakarida yang dihasilkan bakteri akan mengikat partikel tanah dan membentuk agregasi. Penggunaan bakteri <em>Bukholderia anthina </em>MYSP113 dinilai lebih efisien dalam pemanfaatannya untuk memantapkan agregat tanah karena memiliki kemampuan terbaik untuk memantapkan agregat tanah hingga sangat mantap sekali dengan atau tanpa penambahan bahan organik pada periode 60 hari pengamatan.</p><p><em><strong>Abstract</strong></em>. This study aimed to analyze the aggregate stability of soil with sdifferent treatments of aggregate-stabilizing bacteria and organic matter (compost made of mixture of 90% Cyperus pilosus Vahl grass biomass and 10% cattle manure) at different incubation period. Treatments consisted of control, combination of three different isolate with three different composition of organic matter (0%, 0.5%, and 1%). The results showed that the application of aggregate-stabilyzing bacteria to loamy sand soil and organic matter causes a higher bacteria population than without both applications. Klebsiella sp. LW-13 combined with 1% organic matter and Bukholderia anthina MYSP113 which was combined with various levels of organic matter (0 to 1%) showed high aggregation at observation of 60 days after application. The exopolysaccharide produced by bacteria binds soil particles and forms soil aggregation. The use of Bukholderia anthina MYSP113 bacteria is considered to be efficient in its utilization to stabilize soil aggregates because it has the best ability to stabilize soil aggregates to be highly stable with or without the addition of organic matter in the 60-day observation period.</p><p> </p>

The role of extracellular polymeric substances on the sorption of natural organic matter

2012 ◽  
Vol 46 (4) ◽  
pp. 1052-1060 ◽  
Author(s):  
Zhikang Wang ◽  
Christopher M. Hessler ◽  
Zheng Xue ◽  
Youngwoo Seo
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Extracellular Polymeric Substances

scholarly journals Evaluation of the Effects of Organic Matter and Other Soil Characteristics Upon the Aggregate Stability of Some Tropical Soils

1969 ◽  
Vol 43 (4) ◽  
pp. 268-272 ◽  
Author(s):  
M. A. Lugo-López ◽  
J. Juárez, Jr.
Keyword(s):  
Organic Matter ◽  
Soil Aggregates ◽  
Organic Matter Content ◽  
Aggregate Stability ◽  
Tropical Soils ◽  
Development Project ◽  
Matter Content ◽  
Degree Of Stability ◽  
Statistical Studies ◽  
Level Of Significance

This paper reports on statistical studies conducted to evaluate the degree of stability of soil aggregates in terms of the respective organic-matter, clay, and silt contents of selected soils from the Lajas Valley irrigation development project. Simple regression analyses revealed that there was no correlation between aggregate stability and clay or silt content. However, a highly significant correlation was obtained when organic-matter content was considered as the independent variable. In spite of the level of significance only 16 percent of the variability in aggregate stability can be explained on a basis of the soil organic-matter content, thus limiting the possible usefulness of estimates made by using the equation developed.

scholarly journals PENGARUH MEDIA TANAM DAN FREKUENSI PEMBERIAN AIR TERHADAP SIFAT FISIK, KIMIA DAN BIOLOGI TANAH SERTA PERTUMBUHAN JARAK PAGAR

2020 ◽  
Vol 16 (2) ◽  
pp. 64
Author(s):  
DJAJADI DJAJADI ◽  
BAMBANG HELIYANTO ◽  
NURUL HIDAYAH
Keyword(s):  
Organic Matter ◽  
Soil Fertility ◽  
Soil Nutrients ◽  
Sandy Soil ◽  
Jatropha Curcas ◽  
Aggregate Stability ◽  
Growth Media ◽  
Sand Soil ◽  
Water Holding

<p>ABSTRAK</p><p>Lahan pertanian yang didominasi oleh partikel pasir di daerah lahankering iklim kering mempunyai kapasitas yang rendah dalam menyimpanair dan unsur hara, serta rentan terhadap erosi. Penambahan tanah liat,zeolit, dan bahan organik diharapkan dapat meningkatkan kadar unsur haratanah, kadar air tanah, dan pertumbuhan tanaman. Penelitian yangdilakukan dari bulan Mei sampai Desember 2008 ini bertujuan untukmengetahui pengaruh penambahan tanah liat, zeolit dan interaksinyadengan bahan organik terhadap stabilitas makroagregat, kadar unsur haraC, N, P, dan K, daya pegang air tanah berpasir, populasi mikroorganismetanah serta pertumbuhan jarak pagar. Media tanam yang diuji sebanyak 5jenis, yaitu (1) 100% tanah pasir, (2) 95% tanah pasir + 5% tanah liat, (3)95% tanah pasir + 5% zeolit, (4) 94,2% tanah pasir + 5% tanah liat + 0,8%bahan organik, dan (5) 94,2% tanah pasir + 5% zeolit + 0,8% bahanorganik. Untuk mengetahui kemampuan daya pegang air tanah, makaperlakuan jenis media tersebut dikombinasikan dengan perlakuanfrekuensi pemberian air, yaitu dengan interval 7 dan 21 hari sekali.Perlakuan disusun dalam rancangan acak kelompok faktorial denganempat kali ulangan. Hasil penelitian menunjukkan bahwa penambahan 5%tanah liat + 0,8% bahan organik pada tanah berpasir dapat meningkatkanproporsi makroagregat, kadar unsur hara C, N, P, dan K, serta kapasitasdaya pegang air tanah. Penambahan sebanyak 5% zeolit pada tanah pasirmeningkatkan populasi bakteri. Peningkatan populasi jamur lebih dipacudengan frekuensi pemberian air 7 hari sekali. Pertumbuhan tinggi tanamanjarak pagar juga lebih dipercepat oleh pemberian air dengan frekuensi 7hari sekali.</p><p>Kata kunci: Jatropha curcas, pasir, liat, zeolit, bahan organik, kesuburantanah, pengairan</p><p>ABSTRACT</p><p>The role of clay, zeolit, and organic matter in increasingsoil fertility of sandy soil as growth media for Jatrophacurcas</p><p>Agricultural sandy soils have low capability to retain water andnutrients. Addition of clay, zeolit and organic matter to these soils wasexpected to increase macro-aggregate stability, soil nutrients and waterholding capacity. The research had been conducted from May up toDecember 2008 to find out the effect of addition of clay, zeolit, and theirinteractions with organic matter in increasing sandy soil fertility as growthmedia for Jatropha curcas. The study had an objective to quantify theeffect of plant media and frequency of watering on soil macro-aggregatestability, soil nutrients, water holding capacity, soil microorganismspopulation, and growth of J. curcas. Plant growth media tested in thisstudy consisted of 5 types, i.e. (1) 100% sand soil, (2) 95% sand soil + 5%clay soil, (3) 95% sand soil + 5% zeolit, (4) 94.2% sand soil + 5% clay +0.8% organic matter, and (5) 94.2% sand soil + 5% zeolit + 0.8% organicmatter. Watering of plant was divided into two time intervals, i.e. each of 7days and each of 21 days. Results showed that plant media which was amixture of 94.2% sand soil + 5% clay + 0.8% organic matter increasedproportion of maco-aggregate, plant nutrients (C, N, P, K) and soil waterholding capacity. Plant media consisted of mixture of 95% sand soil + 5%zeolit was suitable for development of bacteria population. Acceleratingof growth of J curcas was induced by watering with interval of 7 days.</p><p>Key words: Jatropha curcas, sand, clay, zeolit, organic matter, watering,soil fertility</p>

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