Soil carbon sequestration and density distribution in a Vertosol under different farming practices

Soil Research ◽  
2004 ◽  
Vol 42 (8) ◽  
pp. 875 ◽  
Author(s):  
W. J. Wang ◽  
R. C. Dalal ◽  
P. W. Moody
Keyword(s):  
Seasonal Variations ◽  
Agricultural Soils ◽  
Cropping System ◽  
Subtropical Climate ◽  
Soil Organic C ◽  
Farming Practices ◽  
Winter Cereal ◽  
Organic C ◽  
Fallow Period

Abstract Agricultural soils play an important role in the global carbon (C) cycling and can act as a significant C sink if managed properly. The long-term (33 years) effects of no till (NT) v. conventional till (CT), stubble retention (SR) v. stubble burning (SB), and N fertiliser application (NF) v. nil N fertilisation (N0) on soil organic C sequestration, and their seasonal variations during the fallow period, were studied in a winter cereal–summer fallow cropping system under semi-arid subtropical climate in Queensland, Australia. The function of different density fractions of soil organic C in determining total organic C (TOC) dynamics and sequestration was investigated. Significant effect of NT, SR, or NF on soil organic C level was observed only in the top 10 cm soil and when they were practiced together, with the TOC contents being 1.1 to 3.4 t/ha higher under NT + NF + SR than under other treatments. There were significant seasonal fluctuations in TOC contents at different stages of the fallow period, and the lowest levels of TOC and treatment effects were observed in the late fallow period. Density fractionation of soil organic C showed that light fraction C (<1.6 g/cm3) declined rapidly during the fallow period and did not accumulate substantially in soil. TOC dynamics, either as a consequence of seasonal variations or as a long-term response to different farming practices, were predominantly controlled by the changes in the heavy fraction C (>1.6 g/cm3).

Comparison of structural stability, carbon fractions and chemistry of krasnozem soils from adjacent forest and pasture areas in south-western Victoria

Soil Research ◽  
2002 ◽  
Vol 40 (2) ◽  
pp. 283 ◽  
Author(s):  
M. R. Carter ◽  
J. O. Skjemstad ◽  
R. J. MacEwan
Keyword(s):  
Nmr Spectroscopy ◽  
Structural Stability ◽  
Forest Soils ◽  
Agricultural Soils ◽  
13C Nmr Spectroscopy ◽  
Soil Organic C ◽  
Organic C ◽  
Photo Oxidation ◽  
Western Victoria

Basalt-derived krasnozems are generally well-structured soils; however, there is a concern that intensive agricultural practices may result in an adverse decline in soil organic carbon, organic matter chemistry, and structural quality over time. A study was conducted on loam to silty clay loam krasnozems (Ferrosols) near Ballarat in south-western Victoria to assess changes in soil C, soil structural stability, and C chemistry, at the 0–10 cm soil depth, under 3 paired sites consisting of adjacent long-term forest (Monterey pine or eucalyptus) v. 30 year cropping &lsqb;3 year pasture–2 year crops (potato and a root crop or grain)&rsqb;. Soil structural stability was also characterised in the A and B horizons under long-term eucalyptus and several cropped sites. Organic C levels in the A horizons for all the soils were relatively high, ranging from 46 to 89 g&sol;kg. A lower organic C (30&percnt;), associated mainly with loss of the sand-sized (&gt;53 m) macro-C fraction, and a decrease in exchangeable Ca and Mg was found in the agricultural soils, compared with forest soils. Physically protected C in the &lt;53 m fraction, as indicated by UV photo-oxidation, was similar among soils. Wet sieving indicated a decline of both C and N concentration in water-stable aggregates and the degree of macro-aggregation under agricultural soils, compared with the forest soils. However, soil structural changes under cropping were mainly related to a decline in the &gt;5 mm sized aggregates, with no deleterious increase in the proportion of 0.10 mm aggregates. Solid state 13C NMR spectroscopy indicated a decrease in O-alkyl and alkyl C under pasture and cropping compared with forest soils, which was in agreement with the decline in the macro-C fraction. Characterisation of C chemistry following UV photo-oxidation showed that charcoal C (dominant presence of aryl C) accounted for 30&percnt; of the total soil organic C, while other functional groups (polysaccharides and alkyl C) were probably protected within micro-aggregates. Based on soil organic C and aggregate stability determinations alone, the implications for soil physical quality, soil loss, and diffuse pollution appear minimal. macroorganic carbon, soil aggregation, charcoal, photo-oxidation, potato rotation, CP&sol;MAS 13C NMR spectroscopy.

scholarly journals Effects of long-term tillage, terminating no-till and cropping system on organic C and N, and available nutrients in a Gleysolic soil in Québec, Canada

2018 ◽  
Vol 156 (4) ◽  
pp. 472-480 ◽  
Author(s):  
S. S. Malhi ◽  
A. Légère ◽  
A. Vanasse ◽  
G. Parent
Keyword(s):  
Cropping System ◽  
Light Fraction ◽  
Soil Tillage ◽  
Soil Organic C ◽  
Organic C ◽  
Available Nutrients ◽  
Nitrate N ◽  
No Till ◽  
C And N

AbstractSome biological and chemical properties of a Gleysol were examined after 24 years of soil tillage (chisel plough – CP, mouldboard plough – MP, no-till – NT) and that of ploughing the 24-yr NT (P-NT) once, in two cropping systems (conventional – CONV, organic – ORG) applied over 4 years (2007–2010) of a long-term experiment (autumn 1987–autumn 2011) at La Pocatière, Québec, Canada. The 0–10, 10–20 and 20–30 cm soil depths were sampled in autumn 2011 after a maize trial. Tillage affected light fraction organic carbon (LFOC), light fraction organic nitrogen (LFON) and mineralizable N (Nmin) in soil, with the lowest LFOC, LFON and Nminvalues in the MP treatment. No-till had lower soil pH than the other tillage systems in the 10–20 and 20–30 cm soil depths. Tillage affected the amounts of nitrate-N in 0–10 and 10–20 cm soil depths, with the lowest amounts for MP (4.3 kg nitrate-N/ha) compared with NT (7.2 or 8.5 kg nitrate-N/ha) or CP (7.7 kg nitrate-N/ha). The P-NT had no negative impact on organic C and N, or available nutrients in soil. Cropping system had no effect on soil organic C and N, available nutrients or pH. Findings suggest that long-term NT or CP may result in greater storage of organic C and N in soil and improve available nutrients compared with MP. Ploughing 25-year-old NT plots redistributed available nutrients in the profile but had no negative effect on soil organic C or N.

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

Yield trends, and changes in soil organic-C and available NPK in a long-term rice–wheat system under integrated use of manures and fertilisers

2000 ◽  
Vol 68 (3) ◽  
pp. 219-246 ◽  
Author(s):  
R.L Yadav ◽  
B.S Dwivedi ◽  
Kamta Prasad ◽  
O.K Tomar ◽  
N.J Shurpali ◽  
...  
Keyword(s):  
Soil Organic C ◽  
Organic C ◽  
Yield Trends

Soil resistance under grazed intermediate wheatgrass

2008 ◽  
Vol 88 (5) ◽  
pp. 833-836 ◽  
Author(s):  
M A Liebig ◽  
J R Hendrickson ◽  
J D Berdahl ◽  
J F Karn
Keyword(s):  
Great Plains ◽  
Cropping System ◽  
Soil Bulk Density ◽  
Northern Great Plains ◽  
System Management ◽  
Thinopyrum Intermedium ◽  
Soil Organic C ◽  
Soil Functions ◽  
Organic C ◽  
Intermediate Wheatgrass

Intermediate wheatgrass [Thinopyrum intermedium (Host) Barkw. & D.R. Dewey subsp. intermedium] is a productive, high-quality perennial forage that lacks persistence under grazing. A study was conducted to evaluate the effects of three grazing times on soil bulk density, soil pH, and soil organic C under intermediate wheatgrass. Treatment effects on the three soil attributes were negligible, implying grazing time did not negatively impact intermediate wheatgrass beyond a threshold whereby critical soil functions were impaired. Findings from this study are important in the context of sustainable forage and cropping system management, where maintaining or improving critical soil functions are essential for enhancing agroecosystem sustainability. Key words: Seeded perennial forages, Northern Great Plains, soil organic C

Management of sugarcane harvest residues: consequences for soil carbon and nitrogen

Soil Research ◽  
2007 ◽  
Vol 45 (1) ◽  
pp. 13 ◽  
Author(s):  
Fiona A. Robertson ◽  
Peter J. Thorburn
Keyword(s):  
Microbial Biomass ◽  
Soil Fertility ◽  
Microbial Activity ◽  
Soil N ◽  
Soil Organic C ◽  
Total N ◽  
Organic C ◽  
Soil Microbial ◽  
C And N

The Australian sugar industry is moving away from the practice of burning the crop before harvest to a system of green cane trash blanketing (GCTB). Since the residues that would have been lost in the fire are returned to the soil, nutrients and organic matter may be accumulating under trash blanketing. There is a need to know if this is the case, to better manage fertiliser inputs and maintain soil fertility. The objective of this work was to determine whether conversion from a burning to a GCTB trash management system is likely to affect soil fertility in terms of C and N. Indicators of short- and long-term soil C and N cycling were measured in 5 field experiments in contrasting climatic conditions. The effects of GCTB varied among experiments. Experiments that had been running for 1–2 years (Harwood) showed no significant trash management effects. In experiments that had been running for 3–6 years (Mackay and Tully), soil organic C and total N were up to 21% greater under trash blanketing than under burning, to 0.10 or 0.25 m depth (most of this effect being in the top 50 mm). Soil microbial activity (CO2 production) and soil microbial biomass also increased under GCTB, presumably as a consequence of the improved C availability. Most of the trash C was respired by the microbial biomass and lost from the system as CO2. The stimulation of microbial activity in these relatively short-term GCTB systems was not accompanied by increased net mineralisation of soil N, probably because of the greatly increased net immobilisation of N. It was calculated that, with standard fertiliser applications, the entire trash blanket could be decomposed without compromising the supply of N to the crop. Calculations of possible long-term effects of converting from a burnt to a GCTB production system suggested that, at the sites studied, soil organic C could increase by 8–15%, total soil N could increase by 9–24%, and inorganic soil N could increase by 37 kg/ha.year, and that it would take 20–30 years for the soils to approach this new equilibrium. The results suggest that fertiliser N application should not be reduced in the first 6 years after adoption of GCTB, but small reductions may be possible in the longer term (>15 years).

scholarly journals Soil management effects on organic carbon in isolated fractions of a Gray Luvisol

2006 ◽  
Vol 86 (1) ◽  
pp. 141-151 ◽  
Author(s):  
A. F. Plante ◽  
C. E. Stewart ◽  
R. T. Conant ◽  
K. Paustian ◽  
J. Six
Keyword(s):  
Organic Matter ◽  
Crop Production ◽  
N Fertilization ◽  
Residue Management ◽  
Soil Organic C ◽  
Organic C ◽  
Straw Management ◽  
Soil C ◽  
C Pools

Agricultural management affects soil organic matter, which is important for sustainable crop production and as a greenhouse gas sink. Our objective was to determine how tillage, residue management and N fertilization affect organic C in unprotected, and physically, chemically and biochemically protected soil C pools. Samples from Breton, Alberta were fractionated and analysed for organic C content. As in previous reports, N fertilization had a positive effect, tillage had a minimal effect, and straw management had no effect on whole-soil organic C. Tillage and straw management did not alter organic C concentrations in the isolated C pools, while N fertilization increased C concentrations in all pools. Compared with a woodlot soil, the cultivated plots had lower total organic C, and the C was redistributed among isolated pools. The free light fraction and coarse particulate organic matter responded positively to C inputs, suggesting that much of the accumulated organic C occurred in an unprotected pool. The easily dispersed silt-sized fraction was the mineral-associated pool most responsive to changes in C inputs, whereas the microaggregate-derived silt-sized fraction best preserved C upon cultivation. These findings suggest that the silt-sized fraction is important for the long-term stabilization of organic matter through both physical occlusion in microaggregates and chemical protection by mineral association. Key words: Soil organic C, tillage, residue management, N fertilization, silt, clay

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