Impact of soil organic matter on soil properties—a review with emphasis on Australian soils

Soil Research ◽  
2015 ◽  
Vol 53 (6) ◽  
pp. 605 ◽  
Author(s):  
B. W. Murphy
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Nutrient Cycling ◽  
Soil Properties ◽  
Aggregate Stability ◽  
Relevant Information ◽  
Soil Productivity ◽  
Soil Biology ◽  
Productive Capacity ◽  
Plant Materials

A review has been undertaken into how soil organic matter (SOM) affects a range of soil properties that are important for the productive capacity of soils. The potential effect of varying the amount of SOM in soil on a range of individual soil properties was investigated using a literature search of published information largely from Australia, but also including relevant information from overseas. The soil properties considered included aggregate stability, bulk density, water-holding capacity, soil erodibility, soil colour, soil strength, compaction characteristics, friability, nutrient cycling, cation exchange capacity, soil acidity and buffering capacity, capacity to form ligands and complexes, salinity, and the interaction of SOM with soil biology. Increases in SOM have the capacity to have strong influence only the physical properties of the surface soils, perhaps only the top 10 cm, or the top 20 cm at most. This limits the capacity of SOM to influence soil productivity. Even so, the top 20 cm is a critical zone for the soil. It is where seeds are sown, germinate and emerge. It is where a large proportion of plant materials are added to the soil for decomposition and recycling of nutrients and where rainfall either enters the soil or runs off. Therefore, the potential to improve soil condition in the top 0–20 cm is still critical for plant productivity. The SOM through nutrient cycling such as mineralisation of organic nitrogen to nitrate can have an influence on the soil profile.

scholarly journals Obtaining more benefits from crop residues as soil amendments by application as chemically heterogeneous mixtures

2020 ◽  
Author(s):  
Marijke Struijk ◽  
Andrew P. Whitmore ◽  
Simon R. Mortimer ◽  
Tom Sizmur
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Properties ◽  
Nutrient Availability ◽  
Soil Structure ◽  
Crop Residues ◽  
Soil Amendments ◽  
Aggregate Stability ◽  
Available N ◽  
Nitrogen Levels

Abstract. Crop residues are valuable soil amendments in terms of the carbon and other nutrients they contain, but incorporation of residues does not always translate into increases in nutrient availability, soil organic matter (SOM), soil structure, and overall soil fertility. Studies have demonstrated accelerated decomposition rates of chemically heterogeneous litter mixtures, compared to the decomposition of individual litters, in forest and grassland systems. Mixing high C : N ratio with low C : N ratio amendments may result in greater carbon use efficiency and non-additive benefits in soil properties (i.e. mixture ≠ sum of the parts). We hypothesised that non-additive benefits would accrue from mixtures of low-quality (straw or woodchips) and high-quality (vegetable-waste compost) residues applied before lettuce planting in a full-factorial field experiment. Properties indicative of soil structure and nutrient cycling were used to assess benefits from residue mixtures, including soil respiration, aggregate stability, bulk density, SOM, available and potentially mineralisable N, available P, K and Mg, and crop yield. Soil organic matter and mineral nitrogen levels were significantly and non-additively greater in the straw-compost mixture compared to individual residues, which mitigated the N immobilisation occurring with straw-only applications. Addition of compost significantly increased soil available N, K and Mg levels. Together, these observations suggest that greater nutrient availability improved the ability of decomposer organisms to degrade straw in the straw-compost mixture. We demonstrate that mixtures of crop residues can influence soil properties non-additively. Thus, greater benefits may be achieved by removing, mixing, and re-applying crop residues, than by simply returning them to the soils in situ.

scholarly journals The Soil Organic Matter in Connection with Soil Properties and Soil Inputs

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 779
Author(s):  
Václav Voltr ◽  
Ladislav Menšík ◽  
Lukáš Hlisnikovský ◽  
Martin Hruška ◽  
Eduard Pokorný ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Texture ◽  
Management Practices ◽  
Soil Depth ◽  
Operating Conditions ◽  
Hot Water ◽  
Natural Soil ◽  
Soil Productivity ◽  
Linear Regression Models

The content of organic matter in the soil, its labile (hot water extractable carbon–HWEC) and stable (soil organic carbon–SOC) form is a fundamental factor affecting soil productivity and health. The current research in soil organic matter (SOM) is focused on individual fragmented approaches and comprehensive evaluation of HWEC and SOC changes. The present state of the soil together with soil’s management practices are usually monitoring today but there has not been any common model for both that has been published. Our approach should help to assess the changes in HWEC and SOC content depending on the physico-chemical properties and soil´s management practices (e.g., digestate application, livestock and mineral fertilisers, post-harvest residues, etc.). The one- and multidimensional linear regressions were used. Data were obtained from the various soil´s climatic conditions (68 localities) of the Czech Republic. The Czech farms in operating conditions were observed during the period 2008–2018. The obtained results of ll monitored experimental sites showed increasing in the SOC content, while the HWEC content has decreased. Furthermore, a decline in pH and soil´s saturation was documented by regression modelling. Mainly digestate application was responsible for this negative consequence across all soils in studied climatic regions. The multivariate linear regression models (MLR) also showed that HWEC content is significantly affected by natural soil fertility (soil type), phosphorus content (−30%), digestate application (+29%), saturation of the soil sorption complex (SEBCT, 21%) and the dose of total nitrogen (N) applied into the soil (−20%). Here we report that the labile forms (HWEC) are affected by the application of digestate (15%), the soil saturation (37%), the application of mineral potassium (−7%), soil pH (−14%) and the overall condition of the soil (−27%). The stable components (SOM) are affected by the content of HWEC (17%), soil texture 0.01–0.001mm (10%), and input of organic matter and nutrients from animal production (10%). Results also showed that the mineral fertilization has a negative effect (−14%), together with the soil depth (−11%), and the soil texture 0.25–2 mm (−21%) on SOM. Using modern statistical procedures (MRLs) it was confirmed that SOM plays an important role in maintaining resp. improving soil physical, biochemical and biological properties, which is particularly important to ensure the productivity of agroecosystems (soil quality and health) and to future food security.

Sorption of hydrophobic pesticides to aliphatic components of soil organic matter

2003 ◽  
Author(s):  
Benny Chefetz ◽  
Baoshan Xing
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Pollutants ◽  
Agricultural Soils ◽  
Hydrophobic Interactions ◽  
Spectroscopic Techniques ◽  
Plant Materials ◽  
Hydrophobic Compounds ◽  
High Sorption ◽  
Sorption Mechanisms

Sorption of hydrophobic compounds to aliphatic components of soil organic matter (SOM) is poorly understood even though these aliphatic carbons are a major fraction of SOM. The main source of aliphatic compounds in SOM is above- and below-ground plant cuticular materials (cutin, cutan and suberin). As decomposition proceeds, these aliphatic moieties tend to accumulate in soils. Therefore, if we consider that cuticular material contributes significantly to SOM, we can hypothesize that the cuticular materials play an important role in the sorption processes of hydrophobic compounds (including pesticides) in soils, which has not yet been studied. The overall goal of this research was to illustrate the mechanism and significance of the refractory aliphatic structures of SOM in sorbing hydrophobic compounds (nonionic and weakly polar pesticides). The importance of this study is related to our ability to demonstrate the sorption relationship between key pesticides and an important fraction of SOM. The specific objectives of the project were: (1) To isolate and characterize cuticular fractions from selected plants; (2) To investigate the sorption mechanism of key hydrophobic pesticides and model compounds to cuticular plant materials; (3) To examine the sorption mechanisms at the molecular level using spectroscopic techniques; (4) To investigate the sorption of key hydrophobic pesticides to synthetic polymers; (5) To evaluate the content of cuticular materials in agricultural soils; and (6) To study the effect of incubation of plant cuticular materials in soils on their sorptive capabilities. This project demonstrates the markedly high sorption capacity of various plant cuticular fractions for hydrophobic organic compounds (HOCs) and polar organic pollutants. Both cutin (the main polymer of the cuticle) and cutan biopolymers exhibit high sorption capability even though both sorbents are highly aliphatic in nature. Sorption by plant cuticular matter occurs via hydrophobic interactions and H-bonding interactions with polar sorbates. The cutin biopolymer seems to facilitate reversible and noncompetitive sorption, probably due to its rubbery nature. On the other hand, the epicuticular waxes facilitate enhance desorption in a bi-solute system. These processes are possibly related to phase transition (melting) of the waxes that occur in the presence of high solute loading. Moreover, our data highlight the significance of polarity and accessibility of organic matter in the uptake of nonpolar and polar organic pollutants by regulating the compatibility of sorbate to sorbent. In summary, our data collected in the BARD project suggest that both cutin and cutan play important roles in the sorption of HOCs in soils; however, with decomposition the more condensed structure of the cutin and mainly the cutan biopolymer dominated sorption to the cuticle residues. Since cutin and cutan have been identified as part of SOM and humic substances, it is suggested that retention of HOCs in soils is also controlled by these aliphatic domains and not only by the aromaticrich fractions of SOM.

Soil Organic Matter (SOM) and Nutrient Cycling

2021 ◽  
pp. 383-411
Author(s):  
P. K. Ramachandran Nair ◽  
B. Mohan Kumar ◽  
Vimala D. Nair
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Nutrient Cycling

scholarly journals Relationship of soil properties to fractionation, bioavailability and mobility of lead and zinc in soil

2008 ◽  
Vol 53 (No. 5) ◽  
pp. 225-238 ◽  
Author(s):  
N. Finžgar ◽  
P. Tlustoš ◽  
D. Leštan
Keyword(s):  
Organic Matter ◽  
Regression Analysis ◽  
Soil Organic Matter ◽  
Soil Properties ◽  
Multiple Regression ◽  
Contaminated Soils ◽  
Organic Matter Content ◽  
Clay Content ◽  
Exchange Capacity ◽  
Matter Content

Sequential extractions, metal uptake by <i>Taraxacum officinale</i>, Ruby&rsquo;s physiologically based extraction test (PBET) and toxicity characteristic leaching procedure (TCLP), were used to assess the risk of Pb and Zn in contaminated soils, and to determine relationships among soil characteristics, heavy metals soil fractionation, bioavailability and leachability. Regression analysis using linear and 2nd order polynomial models indicated relationships between Pb and Zn contamination and soil properties, although of small significance (<i>P</i> < 0.05). Statistically highly significant correlations (<i>P</i> < 0.001) were obtained using multiple regression analysis. A correlation between soil cation exchange capacity (CEC) and soil organic matter and clay content was expected. The proportion of Pb in the PBET intestinal phase correlated with total soil Pb and Pb bound to soil oxides and the organic matter fraction. The leachable Pb, extracted with TCLP, correlated with the Pb bound to carbonates and soil organic matter content (<i>R</i><sup>2</sup> = 69%). No highly significant correlations (<i>P</i> < 0.001) for Zn with soil properties or Zn fractionation were obtained using multiple regression.

Soil organic matter in rainfed cropping systems of the Australian cereal belt

Soil Research ◽  
2001 ◽  
Vol 39 (3) ◽  
pp. 435 ◽  
Author(s):  
R. C. Dalal ◽  
K. Y. Chan
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Management Practices ◽  
Performance Indicator ◽  
Annual Rainfall ◽  
Soil Productivity ◽  
Organic C ◽  
Soil C ◽  
Eastern Australia

The Australian cereal belt stretches as an arc from north-eastern Australia to south-western Australia (24˚S–40˚S and 125˚E–147˚E), with mean annual temperatures from 14˚C (temperate) to 26˚C (subtropical), and with annual rainfall ranging from 250 mm to 1500 mm. The predominant soil types of the cereal belt include Chromosols, Kandosols, Sodosols, and Vertosols, with significant areas of Ferrosols, Kurosols, Podosols, and Dermosols, covering approximately 20 Mha of arable cropping and 21 Mha of ley pastures. Cultivation and cropping has led to a substantial loss of soil organic matter (SOM) from the Australian cereal belt; the long-term SOM loss often exceeds 60% from the top 0–0.1 m depth after 50 years of cereal cropping. Loss of labile components of SOM such as sand-size or particulate SOM, microbial biomass, and mineralisable nitrogen has been even higher, thus resulting in greater loss in soil productivity than that assessed from the loss of total SOM alone. Since SOM is heterogeneous in nature, the significance and functions of its various components are ambiguous. It is essential that the relationship between levels of total SOM or its identif iable components and the most affected soil properties be established and then quantif ied before the concentrations or amounts of SOM and/or its components can be used as a performance indicator. There is also a need for experimentally verifiable soil organic C pools in modelling the dynamics and management of SOM. Furthermore, the interaction of environmental pollutants added to soil, soil microbial biodiversity, and SOM is poorly understood and therefore requires further study. Biophysically appropriate and cost-effective management practices for cereal cropping lands are required for restoring and maintaining organic matter for sustainable agriculture and restoration of degraded lands. The additional benefit of SOM restoration will be an increase in the long-term greenhouse C sink, which has the potentialto reduce greenhouse emissions by about 50 Mt CO2 equivalents/year over a 20-year period, although current improved agricultural practices can only sequester an estimated 23% of the potential soil C sink.

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