Long term trends in fertility of soils under continuous cultivation and cereal cropping in southern Queensland. IV. Loss of organic carbon from different density functions

Soil Research ◽  
1986 ◽  
Vol 24 (2) ◽  
pp. 301 ◽  
Author(s):  
RC Dalal ◽  
RJ Mayer
Keyword(s):  
Clay Content ◽  
Continuous Cultivation ◽  
Heavy Fraction ◽  
Light Fraction ◽  
Organic C ◽  
Ethanol Mixture ◽  
Total Soil ◽  
Long Term Trends ◽  
The Difference

Six southern Queensland soils used for cereal cropping for cultivation periods ranging from 20 to 70 years were subjected to density fractionation. The soils were separated into fractions with densities of <2, 2.0-2.2, 2.2-2.4 and >2.4 Mg m-3 using bromoform-ethanol mixture. The < 2 Mg m-3 fraction (light fraction) contained only 1.8-3.2% of the total soil weight, but accounted for 15-32% of total soil organic C. In five clay soils the rate of loss of organic C from the light fraction was 2-11 times greater than that from the heavy fraction (>2 Mg m-3). The higher the clay content the larger was the difference between these two fractions in rate of loss of organic C. It is inferred that the heavy fraction was closely associated with clay in these soils. In a sandy soil, rate of loss of organic C from the heavy fraction was similar to that from the whole soil.

scholarly journals Long term trends in fertility of soils under continuous cultivation and cereal cropping in southern Queensland. II. Total organic carbon and its rate of loss from the soil profile

Soil Research ◽  
1986 ◽  
Vol 24 (2) ◽  
pp. 281 ◽  
Author(s):  
RC Dalal ◽  
RJ Mayer
Keyword(s):  
Activity Ratio ◽  
Clay Content ◽  
Continuous Cultivation ◽  
Stepwise Multiple Regression ◽  
Annual Rainfall ◽  
Aggregation Index ◽  
Organic C ◽  
Long Term Trends ◽  
Kinetics Of

The kinetics of organic C loss were studied in six southern Queensland soils subjected to different periods (0-70 years) of cultivation and cereal cropping. The equation: Ct = Ce + (C0 - Ce)exp(- kt), where C0, Ce and C, are organic C contents initially, at equilibrium and at time k respectively, and k is the rate of loss of organic C from soil, was employed in the study. The parameter k was calculated both for %C (kc) and for weight of organic C/volume of soil (k,), determined by correcting for differences in sampling depth due to changes in bulk density upon cultivation. Mean annual rainfall largely determined both C, and Ce, presumably by influencing the amount of dry matter produced. Values of kc and kw varied greatly among the soils studied. For the 0-0.1 m depth, kw was 0.065, 0.080, 0.180, 0.259, 0.069 and 1.224 year-1 respectively for Waco (black earth - initially grassland), Langland-Logie (grey brown and red clays - brigalow), Cecilvale (grey, brown and red clays - poplar box), Billa Billa (grey, brown and red clays - belah), Thallon (grey, brown and red clays - coolibah) and Riverview (red earths - silver-leaved ironbark). The k values were significantly correlated with organic Chrease activity ratio (r = 0.99***) and reciprocal of clay content (r = 0.97**) of the virgin soils. In stepwise multiple regression analysis, aggregation index (for kc values) or exchangeable sodium percentage (for kw) and organic C/urease activity ratio of soils were significantly associated with the overall rate of loss of organic C. It was inferred, therefore, that the relative inaccessibility and protection of organic matter against microbial and enzymic attack resulted in reduced organic C loss. Losses of organic C from the deeper layers (0-0.2 m, 0-0.3 m) were observed in Waco, Langlands-Logie, Cecilvale and Riverview soils, although generally rate of loss decreased with depth.

Impact of long-term cultivation on the status of organic matter and cadmium in soil

2001 ◽  
Vol 81 (3) ◽  
pp. 349-355 ◽  
Author(s):  
D. F. E. McArthur ◽  
P M Huang ◽  
L M Kozak
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Significant Positive Correlation ◽  
Soil Organic C ◽  
Organic C ◽  
Total Soil ◽  
Total Organic C ◽  
Soil Cd ◽  
Cultivated Soils

Research has suggested a link between the bioavailability of soil Cd and total soil organic matter. However, some research suggested a negative relationship between total soil organic matter and bioavailable soil Cd while other research suggested a positive relationship. This study investigated the relationship between soil Cd and both the quantity and quality of soil organic matter as influenced by long-term cultivation. Two Orthic Chernozemic surface soil samples, one from a virgin prairie and the other from an adjacent cultivated prairie, were collected from each of 12 different sites throughout southern Saskatchewan, Canada. The samples were analyzed for total organic C, total Cd, Cd availability index (CAI), and pH. The nature of the soil organic matter was investigated with 13C Cross Polarization Magic Angle Spinning Nuclear Magnetic Resonance spectroscopy (13C CPMAS NMR). The total soil Cd, CAI, and total soil organic C of the cultivated soils were significantly lower than those of the virgin soils whereas the opposite trend was observed for the soil pH and the aromaticity of the organic C. The reduced CAI in the cultivated soils was related to the increase in both the soil pH and the aromaticity of the organic C. No relationship was found between the CAI and the soil organic C content, but a significant positive correlation was found between total organic C and total Cd in both the virgin and the cultivated soils. As well, a significant positive correlation was found between the fraction of total Cd removed from the soil after long-term cultivation and the corresponding fraction of organic C removed. Key words: Long-term cultivation, soil organic matter, 13C CPMAS NMR, cadmium

Comparison of three carbon determination methods on naturally occurring substrates and the implication for the quantification of 'soil carbon'

Soil Research ◽  
2011 ◽  
Vol 49 (1) ◽  
pp. 27 ◽  
Author(s):  
M. K. Conyers ◽  
G. J. Poile ◽  
A. A. Oates ◽  
D. Waters ◽  
K. Y. Chan
Keyword(s):  
Soil Carbon ◽  
Annual Variation ◽  
Organic Substrates ◽  
Test Procedures ◽  
Organic C ◽  
Soil C ◽  
Long Term Trends ◽  
Carbon Determination ◽  
Almost All

Accounting for carbon (C) in soil will require a degree of precision sufficient to permit an assessment of any trend through time. Soil can contain many chemically and physically diverse forms of organic and inorganic carbon, some of which might not meet certain definitions of ‘soil carbon’. In an attempt to assess how measurements of these diverse forms of C might vary with analytical method, we measured the C concentration of 26 substrates by three methods commonly used for soil C (Walkley–Black, Heanes, and Leco). The Heanes and Leco methods were essentially equivalent in their capture of organic C, but the Leco method captured almost all of the inorganic C (carbonates, graphite). The Heanes and Walkley–Black methods did not measure carbonates but did measure 92% and 9%, respectively, of the C in graphite. All three of the common soil test procedures measured some proportion of the charcoal and of the other burnt materials. The proportion of common organic substrates (not the carbonates, graphite, or soil) that was C by weight ranged from ~10% to 90% based on the Heanes and Leco data. The proportion of the organic fraction of those same substrates, as measured by loss-on-ignition, that was C by weight ranged from 42% to 100%. The relationship between Walkley–Black C and total C (by Heanes and Leco) showed that Walkley–Black C was a variable proportion of total C for the 26 substrates. Finally, the well-known, apparent artefact in the Cr-acid methods was investigated: dichromate digestion should contain at least 7–10 mg C in the sample or over-recovery of C might be reported. Our observation that common soil C procedures readily measure C in plant roots and shoots, and in burnt stubble, means that there will likely be intra-annual variation in soil C, because avoidance of these fresh residues is difficult. Such apparent intra-annual variation in soil C will make the detection of long-term trends problematic.

Long-Term Trends in Prehistoric Fishing and Hunting on Tobago, West Indies

2006 ◽  
Vol 17 (3) ◽  
pp. 316-334 ◽  
Author(s):  
David W. Steadman ◽  
Sharyn Jones
Keyword(s):  
Species Richness ◽  
Relative Abundance ◽  
West Indies ◽  
Sea Turtles ◽  
Food Preferences ◽  
Reef Fishes ◽  
Archaeological Sites ◽  
Long Term Trends ◽  
The Difference

AbstractWe compare the bone assemblages of Milford 1 (TOB-3) and Golden Grove (TOB-13) in Tobago, West Indies. Milford 1 is a small preceramic occupation (ca. 3000-2800 cal B.P.), whereas Golden Grove is a large ceramic-period village (ca. 1700-900 cal B.P.). Species richness at TOB-13 is greater than at TOB-3, both in marine (67 vs. 39 fishes) and terrestrial (32 vs. 9) taxa. Major shifts in marine exploitation from the preceramic to ceramic periods can be seen in relative abundance of tuna, toadfishes, and in fishes inhabiting mangrove and brackish water environments, and decreases in relative abundance of parrotfish, carnivorous reef fishes, and sea turtles. The abundance of tuna bones at TOB-13 is uniquely high among West Indian archaeological sites. For terrestrial taxa, the difference in species richness exceeds the expected, including decreased specialization on big game (peccaries) at TOB-13, with a greater tendency to hunt reptiles, birds, and mammals of all sizes at TOB-3. Factors underlying the shifts in fishing and hunting may include different collection methods and food preferences of non-Arawakan (preceramic) vs. Arawakan (ceramic) peoples, as well as human-induced declines in populations of peccaries, sea turtles, and selected fish species. Another possible factor is site setting, with the inhabitants of TOB-13 having enhanced access to mangrove habitats.

scholarly journals Fixation of ammonium in Finnish soils

1962 ◽  
Vol 34 (1) ◽  
pp. 107-114
Author(s):  
Armi Kaila
Keyword(s):  
Linear Correlation ◽  
Correlation Coefficients ◽  
Clay Content ◽  
Ammonium Nitrogen ◽  
Nitrogen Fertilizers ◽  
Surface Soils ◽  
Organic C ◽  
Mean Values ◽  
The Difference ◽  
Exchangeable Form

The ammonium fixing capacity of Finnish soils was studied by analysing a material of 139 samples from surface soils and 127 samples of deeper layers collected mainly from cultivated soils from various parts of the country. The pH-values of these samples measured in 0.02 N CaCl2-suspension ranged from 3.3 to 7.5, the content of organic C from 0 to 10.1 per cent, and the content of clay (< 2 μ) from 0 to 96 per cent. The ammonium fixing capacity was determined under moist conditions by treating the samples for 24 hours with N NH4CI solution corresponding to 1000 m.e. of NH4-N per 100 g of soil, and removing the easily exchangeable ions by washing with CaCl2 -solutions. The difference in the nitrogen content of treated and untreated samples determined by digesting in concentrated sulfuric acid, was taken to indicate the amount fixed under these conditions. The results varied from 0 to 4.0 m.e./100 g of soil in the surface samples, and from 0 to 15.9 m.e./100 g of the soils from the deeper layers. The corresponding mean values were 1.0 and 3.8 m.e. per 100 g of soil, respectively. The association of the ammonium fixing capacity (1) with the clay content (2), pH (3), and the content of organic C (4) of the samples could be characterized by the following partial linear correlation coefficients; r12;34 = 0.472*** r13;24 = 0.177 r14;23 = –0.313** The total linear correlation coefficient between the ammonium fixing capacity and the fixation of potassium under moist conditions (2.5 m.e. of K added to 100 g of soil) was r = 0.829***. No correlation existed between the ammonium fixing capacity and the content of exchangeable potassium in these samples. Some of the results point to the possibility that in certain soils the coarser fractions, from 2 to 6 μ, or even from 6 to 20 μ, may play an important role in the fixing of ammonium in difficultly exchangeable form. In spite of the fact that under laboratory conditions the ammonium fixing capacity of Finnish soils may be fairly high, even in the surface soils, the conclusion was drawn that usually under the field conditions, the fixation of ammonium ions in difficultly exchangeable form might not reduce the effect of ammonium nitrogen fertilizers to any marked degree.

scholarly journals Variation of soil organic matter depends on light-fraction organic matter under long-term monocropping of different crops  

2021 ◽  
Author(s):  
Futao Zhang ◽  
Yunfa Qiao ◽  
Xiaozeng Han ◽  
Bin Zhang
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Principal Component ◽  
Light Fraction ◽  
Bulk Soil ◽  
Density Fractions ◽  
Chemical Structures ◽  
Light Fraction Organic Matter ◽  
The Difference

Cultivating crops influences soil organic matter (SOM), but the effect of different crops remains unclear, particularly under long-term monocropping. The objective of this study was to identify how different crops influence the content and chemical structures of SOM under long-term monocropping. Here, soils were sampled (0–20 cm) under 27-year soybean and maize monocropping and separated into different physical fractions. The content and chemical structures of SOM in all fractions were determined. SOM contents were higher under soybean than maize in bulk soil and macroaggregates and their light-fractions instead of microaggregates and silt and clay. The difference in SOM chemical structure was observed in aggregates and density fractions rather than bulk soils and supported by the result of principal component analysis. The proportion of O-alkyl C in macro- and microaggregates and all free light fractions and that of aromatic C in mineral-associated fractions were higher, while that of carbonyl C was lower under maize than soybean. These results demonstrated that different crops monocropping influences the content and chemical structures of SOM, and the variations were mainly in the light-fraction SOM and highlight a higher sensitivity of physical fractions than bulk soil to different crops.  

scholarly journals Stability of Woodchips Biochar and Impact on Soil Carbon Stocks: Results from a Two-Year Field Experiment

Forests ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1350
Author(s):  
Irene Criscuoli ◽  
Maurizio Ventura ◽  
Katja Wiedner ◽  
Bruno Glaser ◽  
Pietro Panzacchi ◽  
...  
Keyword(s):  
Climate Change ◽  
Field Experiment ◽  
Priming Effect ◽  
Soil Organic C ◽  
Organic C ◽  
Soil C ◽  
Total Soil ◽  
C Stock ◽  
The Stability

Biochar has been shown to improve soil quality and crop yields. Furthermore, thanks to its high carbon content (C) and stable chemical structure, biochar can sequester C in the soil for a long time, mitigating climate change. However, the variability in published biochar stability in the soil makes verifying this trait under different environmental and agricultural conditions necessary. Moreover, most of the published literature refers to short-term incubation experiments, which are considered to not adequately represent long-term dynamics under field conditions. This article reports the results of a field experiment carried out in a vineyard near Merano, northern Italy, where the stability of woodchips biochar in soil, its impact on the total soil C stocks as well as on the original soil organic C (priming effect) were studied over two years. Vineyard soil (Dystric Eutrochrept) was amended with biochar (25 and 50 t ha−1) alone or together with compost (45 t ha−1) and compared with unamended control soil. Two methods assessed the stability of biochar in soil: the isotopic mass balance approach and the quantification of Benzene PolyCarboxylic Acids (BPCAs), molecular markers of biochar. The amount of C in the soil organic matter (SOM-C) was determined in the amended plots by subtracting the amount of biochar-C from the total soil organic C stock, and the occurrence of priming effect was verified by comparing SOM-C values at the beginning and at the end of the experiment. Results did not show any significant biochar degradation for both application rates, but results were characterized by a high variation. The application of 50 t ha−1 of biochar significantly increased soil C stock while no effect of biochar on the degradation of SOM-C was observed. Results were confirmed in the case of biochar application together with compost. It can be concluded that the use of woodchips biochar as a soil amendment can increase soil C content in the medium term. However, further analyses are recommended to evaluate the impact of biochar on climate change mitigation in the long term.

scholarly journals Comparing temperature of subauroral mesopause over Yakutia with SABER radiometer data for 2002–2014

2017 ◽  
Vol 3 (2) ◽  
pp. 58-63
Author(s):  
Анастасия Аммосова ◽  
Anastasiya Ammosova ◽  
Галина Гаврильева ◽  
Galina Gavrilyeva ◽  
Петр Аммосов ◽  
...  
Keyword(s):  
Spectral Measurements ◽  
Satellite Measurements ◽  
Mesopause Region ◽  
Temperature Variations ◽  
Broadband Emission ◽  
Long Term Trends ◽  
The Difference ◽  
Temperature Time ◽  
Good Agreement

We present the temperature database for the mesopause region, which was collected from spectral measurements of bands O2(0-1) and OH(6-2) with the infrared spectrograph SP-50 at the Maimaga station (63° N; 129.5° E) in 2002–2014. The temperature time series covers 11-year solar cycle. It is compared with the temperature obtained with the Sounding of the At-mosphere using Broadband Emission Radiometry in-strument (SABER, v.1.07 and v.2.0), installed onboard the TIMED satellite. We compare temperatures meas-ured during satellite passes at distances under 500 km from the intersection of the spectrograph sighting line with the hydroxyl emitting layer (~87 km) and oxygen emitting layer (~95 km). The time criterion is 30 min. We observe that there is a seasonal dependence of the difference between the ground-based and satellite measurements. The data obtained using SABER v2.0 show good agreement with the temperatures measured with the infrared digital spectrograph. The analysis we carried out allows us to conclude that a series of rotational temperatures obtained at the Maimaga station can be used to study temperature variations on different time scales including long-term trends at the mesopause height

scholarly journals Source and Accumulation of Soil Carbon along Catena Toposequences over 12,000 Years in Three Semi-Natural Miscanthus sinensis Grasslands in Japan

Agriculture ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 88
Author(s):  
David S. Howlett ◽  
J. Ryan Stewart ◽  
Jun Inoue ◽  
Masanori Saito ◽  
DoKyoung Lee ◽  
...  
Keyword(s):  
Soil Carbon ◽  
Accumulation Rate ◽  
Miscanthus Sinensis ◽  
C4 Plant ◽  
Soil C ◽  
Radiocarbon Age ◽  
Total Soil ◽  
Natural Grasslands ◽  
The Difference

Miscanthus-dominated semi-natural grasslands in Japan appear to store considerable amounts of soil C. To estimate the long-term effect of Miscanthus vegetation on the accumulation of soil carbon by soil biota degradation in its native range, we measured total soil C from the surface to a 1.2 m depth along a catena toposequence in three annually burned grasslands in Japan: Kawatabi, Soni, and Aso. Soil C stock was estimated using a radiocarbon age and depth model, resulting in a net soil C accumulation rate in the soil. C4-plant contribution to soil C accumulation was further estimated by δ13C of soil C. The range of total soil C varied among the sites (i.e., Kawatabi: 379–638 Mg, Soni: 249–484, and Aso: 372–408 Mg C ha−1). Catena position was a significant factor at Kawatabi and Soni, where the toe slope soil C accumulation exceeded that of the summit. The soil C accumulation rate of the whole horizon in the grasslands, derived C mainly from C4 plant species, was 0.05 ± 0.02 (Average ± SE), 0.04 ± 0.00, and 0.24 ± 0.04 Mg C ha−1 yr−1 in Kawatabi, Soni, and Aso, respectively. Potential exists for long-term sequestration of C under M. sinensis, but the difference in the C accumulation rate can be influenced by the catena position and the amount of vegetation.

LONG-TERM TRENDS IN TOTAL SOIL N AS INFLUENCED BY CERTAIN MANAGEMENT PRACTICES

Soil Science ◽  
1977 ◽  
Vol 124 (2) ◽  
pp. 110-116 ◽  
Author(s):  
V. W. MEINTS ◽  
L. T. KURTZ ◽  
S. W. MELSTED ◽  
T. R. PECK
Keyword(s):  
Management Practices ◽  
Soil N ◽  
Total Soil ◽  
Long Term Trends ◽  
Total Soil N
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