Changes in soil organic matter chemical properties after organic amendments

Redox-driven changes in Fe crystallinity and speciation may affect soil organic matter (SOM) stabilization and carbon (C) turnover, with consequent influence on global terrestrial soil organic carbon (SOC) cycling.&#160;Under reducing conditions, increasing concentrations of Fe(II) released in solution from the reductive dissolution of Fe (hydr)oxides may accelerate ferrihydrite transformation, although our understanding of the influence of SOM on these transformations is still lacking.&#160;Here, we evaluated abiotic Fe(II)-catalyzed mineralogical changes in Fe (hydr)oxides in bulk soils and size-fractionated SOM pools (for comparison, fine silt plus clay, FSi+Cl, and fine sand, FSa) of an agricultural soil, unamended or amended with biochar, municipal solid waste compost, and a combination of both.&#160;FSa fractions showed the most significant Fe(II)-catalyzed ferrihydrite transformations with the consequent production of well-ordered Fe oxides irrespective of soil amendment, with the only exception being the compost-amended soils. In contrast, poorly crystalline ferrihydrite still constituted ca. 45% of the FSi+Cl fractions of amended soils, confirming the that the higher SOM content in this fraction inhibits atom exchange between aqueous Fe(II) and the solid phase. Building on our knowledge of Fe(II)-catalyzed mineralogical changes in simple systems, our results evidenced that the mechanisms of abiotic Fe mineral transformations in bulk soils depend on Fe mineralogy, organic C content and quality, and organo-mineral associations that exist across particle-size SOM pools. Our results underline that in the fine fractions the increase in SOM due to organic amendments can contribute to limiting abiotic Fe(II)-catalyzed ferrihydrite transformation, while coarser particle-size fractions represent an understudied pool of SOM subjected to Fe mineral transformations.&#160;

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Soil fertility, organic carbon and fractions of the organic matter at different distances from eucalyptus stumps

Revista Brasileira de Ciência do Solo ◽

10.1590/s0100-06832009000300010 ◽

2009 ◽

Vol 33 (3) ◽

pp. 571-579 ◽

Cited By ~ 4

Author(s):

Geraldo Erli Faria ◽

Nairam Félix de Barros ◽

Roberto Ferreira Novais ◽

Ivo Ribeiro Silva

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Organic Carbon ◽

Soil Layer ◽

Chemical Properties ◽

Soil Surface ◽

Light Fraction ◽

Forest Residues ◽

Chemical Attributes ◽

Topsoil Layer

Knowledge on variations in vertical, horizontal and temporal characteristics of the soil chemical properties under eucalyptus stumps left in the soil is of fundamental importance for the management of subsequent crops. The objective of this work was to evaluate the effect of eucalyptus stumps (ES) left after cutting on the spatial variability of chemical characteristics in a dystrophic Yellow Argisol in the eastern coastal plain region of Brazil. For this purpose, ES left for 31 and 54 months were selected in two experimental areas with similar characteristics, to assess the decomposition effects of the stumps on soil chemical attributes. Soil samples were collected directly around these ES, and at distances of 30, 60, 90, 120 and 150 cm away from them, in the layers 0-10, 10-20 and 20-40 cm along the row of ES, which is in-between the rows of eucalyptus trees of a new plantation, grown at a spacing of 3 x 3 m. The soil was sampled in five replications in plots of 900 m² each and the samples analyzed for pH, available P and K (Mehlich-1), exchangeable Al, Ca and Mg, total organic carbon (TOC) and C content in humic substances (HS) and in the free light fraction. The pH values and P, K, Ca2+, Mg2+ and Al3+ contents varied between the soil layers with increasing distance from the 31 and 54-monthold stumps. The highest pH, P, K, Ca2+ and Mg2+ values and the lowest Al3+ content were found in the surface soil layer. The TOC of the various fractions of soil organic matter decreased with increasing distance from the 31 and 54-month-old ES in the 0-10 and 10-20 cm layers, indicating that the root (and stump) cycling and rhizodeposition contribute to maintain soil organic matter. The C contents of the free light fraction, of the HS and TOC fractions were higher in the topsoil layer under the ES left for 31 months due to the higher clay levels of this layer, than in those found under the 54-month-old stumps. However, highest C levels of the different fractions of soil organic matter in the topsoil layer reflect the deposition and maintenance of forest residues on the soil surface, mainly after forest harvest.

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Mechanisms of improving coastal saline-alkali soil by periphyton

10.22541/au.161115527.78762010/v1 ◽

2021 ◽

Author(s):

Ye Zhu ◽

Tianyun Shao ◽

Yujie Zhou ◽

Xiumei Gao ◽

Xiaohua Long ◽

...

Keyword(s):

Organic Matter ◽

Enzyme Activity ◽

Soil Organic Matter ◽

Relative Abundance ◽

Ph Value ◽

Chemical Properties ◽

Functional Genes ◽

Control Soil ◽

Alkali Soil ◽

Unplanted Soil

Periphyton plays an indispensable role in coastal saline-alkali land, but its function is poorly understood. Soil physical and chemical properties (pH value, salinity, soil organic matter), enzyme activity and microbial diversity (based on 16s rDNA, ITS and functional genes) were measured in periphyton formed on rice-growing coastal saline-alkali soil modified by a new type of soil conditioner. The results showed that the content of organic matter and catalase activity in periphyton were significantly higher than in the unplanted control soil. Soil pH and salinity were decreased in periphyton compared to the unplanted control soil. Based on the relative abundance, bacterial genera Desulfomicrobium, Rhodobacter, cyanobacterium_scsio_T−2, Gemmatimonas, and Salinarimonas as well as fungal genus Fusarium were more abundant in periphyton than the unplanted control soil. In terms of functional genes, the cbbM and cbbL sequencing showed higher abundance of Hydrogenophaga, Rhodovulum, Magnetospira, Leptothrix, and Thiohalorhabdus, whereas the nifH sequencing indicated higher abundance of Cyanobacteria in the periphyton compared to the unplanted soil. The relative abundance and community structure of soil microorganisms were improved by periphyton, thus reducing soil salinity and pH, increasing soil organic matter and enzyme activity. This indicated that the periphyton can improve the conditions and offer a suitable environment for plant growth in coastal saline-alkali soil.

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Effect of Tillage and Cover Crop on Fluometuron Adsorption and Degradation under Controlled Conditions

Weed Science ◽

10.1017/s0043174500077067 ◽

1994 ◽

Vol 42 (4) ◽

pp. 629-634 ◽

Cited By ~ 18

Author(s):

Blake A. Brown ◽

Robert M. Hayes ◽

Donald D. Tyler ◽

Thomas C. Mueller

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Soil Ph ◽

Cover Crop ◽

Soil Depth ◽

Organic Matter Content ◽

Chemical Properties ◽

Exchange Capacity ◽

Matter Content ◽

No Till

Fluometuron adsorption and degradation were determined in soil collected at three depths from no-till + no cover, conventional-till + no cover, no-till + vetch cover, and conventional-till + vetch cover in continuous cotton. These combinations of tillage + cover crop + soil depth imparted a range of organic matter and pH to the soil. Soil organic matter and pH ranged from 0.9 to 2.5% and from 4.7 to 6.5, respectively. Fluometuron adsorption was affected by soil depth, tillage, and cover crop. In surface soils (0 to 4 cm), fluometuron adsorption was greater in no-till + vetch plots than in conventional-tilled + no cover plots. Soil adsorption of fluometuron was positively correlated with organic matter content and cation exchange capacity. Fluometuron degradation was not affected by adsorption, and degradation empirically fit a first-order model. Soil organic matter content had no apparent effect on fluometuron degradation rate. Fluometuron degradation was more rapid at soil pH > 6 than at pH ≤ 5, indicating a potential shift in microbial activity or population due to lower soil pH. Fluometuron half-life ranged from 49 to 90 d. These data indicate that tillage and cover crop may affect soil dissipation of fluometuron by altering soil physical and chemical properties that affect fluometuron degrading microorganisms or bioavailability.

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Soil Organic Matter Quality From Soils Cropped by Traditional Peasants

Sustainable Agriculture Research ◽

10.5539/sar.v3n4p63 ◽

2014 ◽

Vol 3 (4) ◽

pp. 63

Author(s):

Luciano Pasqualoto Canellas ◽

Riccardo Spaccini ◽

Natalia De Oliveira Aguiar ◽

Fabio Lopes Olivares

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Root Growth ◽

High Performance ◽

Chemical Properties ◽

Size Exclusion ◽

Native Forest ◽

Organic Matter Quality ◽

African Descendants ◽

Exclusion Chromatography

In this work we have analyzed soil samples from Oxisols collected from two traditional communities, one formed by Guarany Indians at South of Brazil and other by African descendants on North of Rio de Janeiro State, Brazil. The content and fractional composition of humus was investigated and the isolated humic acids (HAs) were characterized by elemental composition, 13C solid-state nuclear magnetic resonance, and high-performance size exclusion chromatography. The bioactivity of HAs was evaluated considering the effects on root growth of maize seedlings. Chemical properties from adjacent soils under native forest were used as control samples. The local field sites matching the traditional cropping requirements, were characterized by higher soil chemical fertility and soil organic matter hydrophobicity, as compared to the land plots considered as inadequate by rural peasants. The HAs from cropped soils revealed significant differences in respect to content, hydrophobicity, biostimulation and molecular dimension. Although all humic extracts promoted, both, root growth and the stimulation of lateral root emergence over control, the HAs from preferential local sites, revealed a larger bioactivity response on root stimulation even at lower concentration. The assessment of soil quality issued by local farmers, showed a valuable fitting with bio-chemical fertility indicators and SOM hydrophobicity.

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THE EFFECT OF VARIOUS ORGANIC AMENDMENTS ON CERTAIN CHEMICAL PROPERTIES OF SOIL, ON PLANT NUTRIENT LEVELS IN STRAWBERRY FOLIAGE AND ON FRUIT YIELDS

Canadian Journal of Plant Science ◽

10.4141/cjps62-071 ◽

1962 ◽

Vol 42 (3) ◽

pp. 437-444

Author(s):

W. B. Collins ◽

R. F. Bishop

Keyword(s):

Organic Matter ◽

Total Nitrogen ◽

Soil Acidity ◽

Organic Amendments ◽

Chemical Properties ◽

Peat Moss ◽

Plant Nutrient ◽

Phosphorus Level ◽

Phosphorus Status ◽

Properties Of Soil

In a field experiment applications of manure decreased soil acidity but increased total nitrogen, organic matter and adsorbed plus easily acid–soluble phosphorus. Where either peat moss or sawdust was applied there was an increase in soil acidity, total nitrogen and organic matter. The effects of other treatments, e.g., hay and hay compost, were less marked.The phosphorus level in strawberry leaf samples from manured plots reflected the improved phosphorus status of the soil but none of the treatments resulted in significant differences in levels of nitrogen, potassium or calcium in the leaves.All treatments gave highly significant increases in yield. However, the yield with either hay compost or hay was significantly higher than with manure.

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