Water-stable aggregation and organic matter in four soils under conventional and zero tillage

1996 ◽  
Vol 76 (3) ◽  
pp. 387-393 ◽  
Author(s):  
A. J. Franzluebbers ◽  
M. A. Arshad
Keyword(s):  
Organic Matter ◽  
Clay Soil ◽  
Clay Content ◽  
Zero Tillage ◽  
Clay Loam ◽  
Soil Organic C ◽  
Organic C ◽  
Peace River ◽  
River Region ◽  
Soil Exposure

Zero tillage management reduces soil exposure and disturbance and, therefore, may improve soil aggregation and organic matter sequestration under some environments. We determined the distribution and soil organic C (SOC) content of five water-stable aggregate (WSA) classes at depths of 0–50, 50–125 and 125–200 mm in a loam, a slit loam, a clay loam, and a clay soil managed for 4–16 yr under conventional shallow tillage (CT) and zero tillage (ZT) in the Peace River region of northern Alberta and British Columbia. Macroaggregation (> 0.25 mm and mean weight diameter (MWD) were greater under ZT than under CT in coarse-textured soils at a depth of 0–125 mm. Under CT, macroaggregation and MWD increased with increasing clay content, thereby reducing the potential of ZT to improve these properties in soils with high clay content. Concentration of SOC tended to be greatest in macroaggregates and lowest in microaggregates of coarse-textured soils, but was not different among WSA classes of fine-textured soils. Soil organic C content of macroaggregates under ZT was 0.34, 0.40, 0.62, and 0.16 kg m−2 greater than under CT at a depth of 0–200 mm in the loam, silt loam, clay loam and clay soil, respectively. Our results suggest that implementation of ZT in this cold semiarid climate can quickly improve WSA of coarse-textured soils and potentially increase SOC sequestration, albeit more slowly than in warmer more humid climates, when macroaggregation is improved. Key words: Aggregation, soil organic matter, soil texture, tillage

Long-term effects of tillage and crop rotations on soil organic C and total N in a clay soil in southwestern Saskatchewan

1996 ◽  
Vol 76 (3) ◽  
pp. 395-401 ◽  
Author(s):  
C. A. Campbell ◽  
B. G. McConkey ◽  
R. P. Zentner ◽  
F. Selles ◽  
D. Curtin
Keyword(s):  
Organic Matter ◽  
Clay Soil ◽  
Clay Content ◽  
Well Being ◽  
Soil Organic C ◽  
N Content ◽  
Total N ◽  
Organic C ◽  
Cropping Frequency ◽  
C And N

Soil organic matter contributes to the productivity and physical well-being of soils. An 11-yr study was conducted on a clay soil in the Brown soil zone in southwestern Saskatchewan to determine the influence of tillage and cropping frequency on soil organic C and total N content. Carbon and N behaved in a similar manner. Cropping frequency did not affect soil organic C or total N content, but soil C and N were greater under no-tillage (NT) than under mechanically tilled continuous wheat (Triticum aestivum L.) (Cont W) and fallow-wheat (F-W) rotations. Effects were apparent in the 0– to 7.5– and 7.5– to 15-cm depths. Over the 11-yr period, F-W (minimum tillage) gained no additional C; Cont W (conventional tillage) gained 2 t C ha−1, and both Cont W (NT) and F-W (NT) gained 5 t C ha−1. Changes in organic C and N were greatest in the final 4 yr of the experiment when crop residue production was greatest. Using data from two similar experiments conducted during the same period on soils differing in texture, we demonstrated that C gains were directly related to clay content of the soils. Thus, when attempting to estimate C storage in soils, we must consider both residue input and soil clay content. Key words: Organic C, total N, organic matter, soil texture, bulk density

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

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

Simulation of soil carbon dynamics in Australia with {\sc Roth C}

2021 ◽  
Author(s):  
Raphael Viscarra Rossel ◽  
Juhwan Lee ◽  
Mingxi Zhang ◽  
Zhongkui Luo ◽  
YingPing Wang
Keyword(s):  
C:N Ratio ◽  
Clay Content ◽  
Natural Environments ◽  
Soil Organic C ◽  
Total N ◽  
Organic C ◽  
Continental Scale ◽  
C Stocks ◽  
C Decomposition ◽  
Soil Measurements

<p>We simulated soil organic carbon (C) dynamics across Australia with the Rothamsted carbon model ({\sc Roth C}) by connecting new spatially-explicit soil measurements and data with the model. This helped us to bridge the disconnection that exists between datasets used to inform the model and the processes that it depicts. We compiled publicly available continental-scale datasets and pre-processed, standardised and configured them to the required spatial and temporal resolutions. We then calibrated {\sc Roth C} and run simulations to estimate the baseline soil organic C stocks and composition in the 0--0.3~m layer at 4,043 sites in cropping, modified grazing, native grazing, and natural environments across Australia. We used data on the C fractions, the particulate, mineral associated, and resistant organic C (POC, MAOC and ROC, respectively) to represent the three main C pools in the {\sc Roth C} model's structure.<span class="Apple-converted-space">  </span>The model explained 97--98\% of the variation in measured total organic C in soils under cropping and grazing, and 65\% in soils under natural environments. We optimised the model at each site and experimented with different amounts of C inputs to simulate the potential for C accumulation under constant and chainging climate in a 100-year simulation. Soils under native grazing were the most potentially vulnerable to C decomposition and loss, while soils under natural environments were the least vulnerable. An empirical assessment of the controls on the C change showed that climate, pH, total N, the C:N ratio, and cropping were the most important controls on POC change. Clay content and climate were dominant controls on MAOC change. Consistent and explicit soil organic C simulations improve confidence in the model's estimations, contributing to the development of sustainable soil management under global change.<span class="Apple-converted-space"> </span></p>

Simulation of soil organic carbon and nitrogen changes in cereal and pasture systems of southern Australia

Soil Research ◽  
1993 ◽  
Vol 31 (4) ◽  
pp. 481 ◽  
Author(s):  
MR Carter ◽  
WJ Parton ◽  
IC Rowland ◽  
JE Schultz ◽  
GR Steed
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Plant Biomass ◽  
Subterranean Clover ◽  
Farming Systems ◽  
Triticum Aestivum L ◽  
Soil Organic C ◽  
Total N ◽  
Organic C

Maintenance and improvement of soil organic matter levels is an important concern in dryland farming systems of temperate regions. The Century soil organic matter model was used to simulate changes in soil organic C and total N under long-term wheat (Triticum aestivum L.) and pasture rotations at five sites in southern Australia. Average declines in soil organic C and total N of 14 and 10%, respectively, in continuous and wheat-fallow systems over a 10 to 20 year period were closely simulated by the model at each site. Additions of N fertilizer (80 kg N ha-1), which prevented soil organic matter decline in continuous wheat systems, was also well represented by the model. Trends in soil organic matter under long-term legume pasture were not adequately simulated by the model, probably due to the 'annual' nature of subterranean clover (Trifolium subterranean L.) in dry seasons and subsequent changes in the ratio of live to dead plant biomass and shoot to root ratios. Overall, the study emphasizes the importance of adequate total plant C production to prevent a decline in soil organic C.

TRACE ELEMENTS IN AGRICULTURAL SOILS OF NORTHWESTERN ALBERTA

1990 ◽  
Vol 70 (3) ◽  
pp. 277-288 ◽  
Author(s):  
Y. K. SOON ◽  
S. ABBOUD
Keyword(s):  
Agricultural Soils ◽  
Clay Content ◽  
Ammonium Bicarbonate ◽  
Surface Soils ◽  
Peace River ◽  
River Region ◽  
Trace Element Contents ◽  
Lead Zinc ◽  
Extractable Metals ◽  
Nickel Lead

Fifty-two surface soils and 11 subsoils collected from agricultural soils of the Peace River region of northwestern Alberta were analyzed for total and extractable contents of Cd, Cr, Cu, Mn, Ni, Pb and Zn. The purpose of this survey was to build up a data base on trace element contents of agricultural and environmental concerns for soils of this region. Extractable amounts were determined by DTPA-ammonium bicarbonate, 0.05 M EDTA, 0.1 M HCl and saturation extractions. Total Cd, Cr, Cu, Mn and Pb concentrations were similar to average values for "world" soils; Ni was less than and Zn greater than "world" average. Total Cr was higher and total Pb lower than average values reported for Canadian soils. Total Cd, Cu, Ni, Pb and Zn were similar in surface and subsurface soils. Extractable Cd, Mn, Ni and Zn tended to be greater in surface soils compared to subsoils; Cu and Pb were higher in the clay-enriched subsoils. Among the surface soils, soils with higher amounts of organic matter contained greater amounts of total and extractable metals with few exceptions. Clay content was also closely correlated with the distribution and content of Cu, Pb and Cr. Few, if any, of the soils would be expected to be deficient in Cu, Mn or Zn for the production of crops. Key words: Cadmium, copper, chromium, manganese, nickel, lead, zinc

scholarly journals Simulation of soil carbon dynamics in Australia under a framework that better connects spatially explicit data with Rᴏᴛʜ C

2020 ◽  
Author(s):  
Juhwan Lee ◽  
Raphael A. Viscarra Rossel ◽  
Zhongkui Luo ◽  
Ying Ping Wang
Keyword(s):  
C:N Ratio ◽  
Clay Content ◽  
Spatially Explicit ◽  
Natural Environments ◽  
Soil Organic C ◽  
Total N ◽  
Organic C ◽  
Soil C ◽  
Continental Scale ◽  
C Stocks

Abstract. We simulated soil organic carbon (C) dynamics across Australia with the Rothamsted carbon model (Rᴏᴛʜ C) under a framework that connects new spatially-explicit soil measurements and data with the model. Doing so helped to bridge the disconnection that exists between datasets used to inform the model and the processes that it depicts. Under this framework, we compiled continental-scale datasets and pre-processed, standardised and configured them to the required spatial and temporal resolutions. We then calibrated Rᴏᴛʜ C and run simulations to predict the baseline soil organic C stocks and composition in the 0–0.3 m layer at 4,043 sites in cropping, modified grazing, native grazing, and natural environments across Australia. The Rᴏᴛʜ C model uses measured C fractions, the particulate, humus, and resistant organic C (POC, HOC and ROC, respectively) to represent the three main C pools in its structure. The model explained 97–98 % of the variation in measured total organic C in soils under cropping and grazing, and 65 % in soils under natural environments. We optimised the model at each site and experimented with different amounts of C inputs to predict the potential for C accumulation in a 100-year simulation. With an annual increase of 1 Mg C ha−1 in C inputs, the model predicted a potential soil C increase of 13.58 (interquartile range 12.19–15.80), 14.21 (12.38–16.03), and 15.57 (12.07–17.82) Mg C ha−1 under cropping, modified grazing and native grazing, and 3.52 (3.15–4.09) Mg C ha−1 under natural environments. Soils under native grazing were the most potentially vulnerable to C decomposition and loss, while soils under natural environments were the least vulnerable. An empirical assessment of the controls on the C change showed that climate, pH, total N, the C:N ratio, and cropping were the most important controls on POC change. Clay content and climate were dominant controls on HOC change. Consistent and explicit soil organic C simulations improve confidence in the model's predictions, contributing to the development of sustainable soil management under global change.

Effect of crop rotations and cultural practices on soil organic matter, microbial biomass and respiration in a thin Black Chernozem

1991 ◽  
Vol 71 (3) ◽  
pp. 363-376 ◽  
Author(s):  
C. A. Campbell ◽  
V. O. Biederbeck ◽  
R. P. Zentner ◽  
G. P. Lafond
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Microbial Biomass ◽  
Cultural Practices ◽  
Respiratory Activity ◽  
Crop Rotations ◽  
Microbial Biomass C ◽  
Soil Organic C ◽  
Organic C ◽  
C And N

The effects of crop rotations and various cultural practices on soil organic matter quantity and quality in a Rego, Black Chernozem with a thin A horizon were determined in a long-term study at Indian Head, Saskatchewan. Variables examined included: fertilization, cropping frequency, green manuring, and inclusion of grass-legume hay crop in predominantly spring wheat (Triticum aestivum L.) production systems. Generally, fertilizer increased soil organic C and microbial biomass in continuous wheat cropping but not in fallow-wheat or fallow-wheat-wheat rotations. Soil organic C, C mineralization (respiration) and microbial biomass C and N increased (especially in the 7.5- to 15-cm depth) with increasing frequency of cropping and with the inclusion of legumes as green manure or hay crop in the rotation. The influence of treatments on soil microbial biomass C (BC) was less pronounced than on microbial biomass N. Carbon mineralization was a good index for delineating treatment effects. Analysis of the microbial biomass C/N ratio indicated that the microbial suite may have been modified by the treatments that increased soil organic matter significantly. The treatments had no effect on specific respiratory activity (CO2-C/BC). However, it appeared that the microbial activity, in terms of respiration, was greater for systems with smaller microbial biomass. Changes in amount and quality of the soil organic matter were associated with estimated amount and C and N content of plant residues returned to the soil. Key words: Specific respiratory activity, crop residues, soil quality, crop rotations

Total soil organic matter and its labile pools following mulga (Acacia aneura) clearing for pasture development and cropping 1. Total and labile carbon

Soil Research ◽  
2005 ◽  
Vol 43 (1) ◽  
pp. 13 ◽  
Author(s):  
R. C. Dalal ◽  
B.P. Harms ◽  
E. Krull ◽  
W.J. Wang
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Land Use Change ◽  
Soil Organic C ◽  
Organic Matter Quality ◽  
Organic C ◽  
Soil C ◽  
Acacia Aneura ◽  
Soil Organic Matter Quality

Mulga (Acacia aneura) dominated vegetation originally occupied 11.2 Mha in Queensland, of which 12% has been cleared, mostly for pasture production, but some areas are also used for cereal cropping. Since mulga communities generally occupy fragile soils, mostly Kandosols and Tenosols, in semi-arid environments, clearing of mulga, which continues at a rate of at least 35 000 ha/year in Queensland, has considerable impact on soil organic carbon (C), and may also have implications for the greenhouse gas emissions associated with land use change in Australia. We report here the changes in soil C and labile C pools following mulga clearing to buffel pasture (Cenchrus ciliaris) and cereal (mostly wheat) cropping for 20 years in a study using paired sites. Soil organic C in the top 0.05 m of soil declined by 31% and 35% under buffel pasture and cropping, respectively. Land use change from mulga to buffel and cropping led to declines in soil organic C of 2.4 and 4.7 t/ha, respectively, from the top 0.3 m of soil. Using changes in the δ13C values of soil organic C as an approximate representation of C derived from C3 and C4 vegetation from mulga and buffel, respectively, up to 31% of soil C was C4-derived after 20 years of buffel pasture. The turnover rates of mulga-derived soil C ranged from 0.035/year in the 0–0.05 m depth to 0.008/year in the 0.6–1 m depths, with respective turnover times of 29 and 133 years. Soil organic matter quality, as measured by the proportion/amount of labile fraction C (light fraction, < 1.6 t/m3) declined by 55% throughout the soil profile (0–1 m depth) under both pasture and cropping. There is immediate concern for the long-term sustainable use of land where mulga has been cleared for pasture and/or cropping with a continuing decline in soil organic matter quality and, hence, soil fertility and biomass productivity. In addition, the removal of mulga forest over a 20-year period in Queensland for pasture and cropping may have contributed to the atmosphere at least 12 Mt CO2-equivalents.

RESPONSE OF BARLEY AND ALFALFA TO LIMING OF SOLONETZIC, PODZOLIC AND GLEYSOLIC SOILS OF THE PEACE RIVER REGION

1967 ◽  
Vol 47 (1) ◽  
pp. 15-21 ◽  
Author(s):  
P. B. Hoyt ◽  
A. M. F. Hennig ◽  
J. L. Dobb
Keyword(s):  
British Columbia ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Ph ◽  
Field Trials ◽  
Northern Region ◽  
Greenhouse Experiment ◽  
Peace River ◽  
Alfalfa Hay ◽  
River Region

In a greenhouse experiment, lime applied to soils from a northern region of Alberta and British Columbia generally caused decreases in barley yields when no P was added and increases when P was added. Liming usually gave increases in alfalfa yields whether P was added or not. These changes in yields of barley and alfalfa were inversely related to soil organic matter and those of alfalfa were also inversely related to soil pH. Soluble Al in these soils, extracted by dilute HCl (pH 2.4), was inversely related to both soil organic matter and pH, and probably because of this, the yield changes were better correlated with soluble Al than with pH. In field trials placed near six of the 28 sampling sites, lime applications gave yield increases of bromegrass-alfalfa hay similar to those for alfalfa in the greenhouse experiment.

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