Characterizing organic matter retention for surface soils in eastern Canada using density and particle size fractions

2003 ◽  
Vol 83 (1) ◽  
pp. 11-23 ◽  
Author(s):  
M. R. Carter ◽  
D. A. Angers ◽  
E. G. Gregorich ◽  
M. A. Bolinder
Keyword(s):  
Organic Matter ◽  
Soil Depth ◽  
Light Fraction ◽  
Degree Of Saturation ◽  
Soil Organic C ◽  
Eastern Canada ◽  
Organic C ◽  
Size Fractions ◽  
Capacity Level ◽  
C And N

Interest in the storage of organic matter in terrestrial ecosystems has identified a need to better understand the accumulation and retention of organic C and N in soil. The proportions of C and N associated with clay and silt particles (i.e., “capacity level”), water-stable macro-aggregates (WSA) (>250 µm), particulate (POM) (>53 µm), and light fraction (LF) organic matter, for the 0- to 10-cm soil depth, were assessed at 14 agricultural experimental sites established on Gleysolic, Podzolic, Luvisolic , and Brunisolic soils in the cool, humid region of eastern Canada. Organic C and N in the clay plus silt particles was at or near the capacity level for soils with clay plus silt content < 40%. For soils with >60% clay plus silt, the degree of saturation was 65–70% indicating a potential for further organic C and N retention. The mean proportion of C and N found in the POM was 22 and 27%, whil e the LF organic matter contained 7 and 5% C and N, respectively. Mean soil WSA content, determined by wet-sieving analysis, was 42% for air-dry soil and 54% for wetted soil, and was significantly (P < 0.05) related to both soil clay plus silt (r = 0.65) and organic C (r = 0.54). Water-stable macro-aggregate C content was proportional to soil organic C (r = 0.96, P < 0.01). At four of the sites, where soil C and N were influenced by management, an increasing level of soil organic C and N was associated with both the clay plus silt particles and the POM fraction until the former was saturated. Once the capacity level was saturated, further organic C and N accumulation was associated with the POM fraction. Although stabilized organic C and N in soil exists as a continuum, both soil particle and particulate fractions provided a practical approach to monitor, quantify and differentiate the storage and retention of C and N in soils of eastern Canada. Key words: Soil organic matter, clay plus silt associated organic C and N, size fractions, particulate organic matter, light fraction organic matter, water-stable macro-aggregates, organic amendments, Canada

Free light fraction carbon and nitrogen, a physically uncomplexed soil organic matter distribution within subtropical grass and leucaena–grass pastures

Soil Research ◽  
2018 ◽  
Vol 56 (8) ◽  
pp. 820 ◽  
Author(s):  
K. A. Conrad ◽  
R. C. Dalal ◽  
D. E. Allen ◽  
R. Fujinuma ◽  
Neal W. Menzies
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Depth ◽  
Light Fraction ◽  
Grass Species ◽  
Pasture Grass ◽  
Total N ◽  
Δ13c And Δ15n ◽  
Organic C ◽  
C And N

Quantifying the size and turnover of physically uncomplexed soil organic matter (SOM) is crucial for the understanding of nutrient cycling and storage of soil organic carbon (SOC). However, the C and nitrogen (N) dynamics of SOM fractions in leucaena (Leucaena leucocephala)–grass pastures remains unclear. We assessed the potential of leucaena to sequester labile, free light fraction (fLF) C and N in soil by estimating the origin, quantity and vertical distribution of physically unprotected SOM. The soil from a chronosequence of seasonally grazed leucaena stands (0–40 years) was sampled to a depth of 0.2m and soil and fLF were analysed for organic C, N and δ13C and δ15N. On average, the fLF formed 20% of SOC and 14% of total N stocks in the upper 0.1m of soil from leucaena rows and showed a peak of fLF-C and fLF-N stocks in the 22-year-stand. The fLF δ13C and fLF δ15N values indicated that leucaena produced 37% of fLF-C and 28% of fLF-N in the upper 0.1m of soil from leucaena rows. Irrespective of pasture type or soil depth, the majority of fLF-C originated from the accompanying C4 pasture-grass species. This study suggests that fLF-C and fLF-N, the labile SOM, can form a significant portion of total SOM, especially in leucaena–grass pastures.

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

Sensitivity of total, light fraction and mineralizable organic matter to management practices in a Lethbridge soil

1994 ◽  
Vol 74 (2) ◽  
pp. 131-138 ◽  
Author(s):  
E. Bremer ◽  
H. H. Janzen ◽  
A. M. Johnston
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Depth ◽  
Crop Management ◽  
Light Fraction ◽  
Yield Response ◽  
Native Grass ◽  
Organic C ◽  
Total Light ◽  
Light Fraction Organic Matter

Crop management influences the quantity and quality of organic matter in agricultural soils. A crop rotation study established at Lethbridge, Alberta in 1951 was sampled in September 1992 to determine the effect of crop management on total, light fraction and mineralizable (10-wk) organic matter contents. Spring wheat was the dominant cropping system; treatments examined include fallow frequency, forage hay production in rotation, manure amendment, N fertilizer application, and native grass. The two latter treatments were introduced in 1985. Total and light fraction organic matter did not vary among phases of the rotation whereas mineralized C tended to be lowest during and shortly after a fallow phase. When averaged across rotation phases, total, light fraction, and mineralized organic matter were enhanced by reduced fallow frequency, manure additons, hay production and native grass. Highest concentrations of total and labile organic concentrations in the 0- to 7.5-cm soil depth were generally found in the continuously-cropped wheat and native grass treatments. Hay production significantly increased soil organic matter in the 15- to 30-cm soil depth. Nitrogen fertilization did not increase soil organic matter in this study, likely because of minimal yield response over the treatment period. Sensitivity of the various indicators to treatment [(highest–lowest)/lowest] was 0.2 for total, 2.5 for light fraction, and 1.5 for mineralized soil organic C. Light fraction organic matter was the most robust indicator of management-induced effects on soil organic matter. Key words: Labile organic matter, fallow frequency, forage hay production, manure, native grass

Turnover of soil organic matter and storage of corn residue carbon estimated from natural 13C abundance

1995 ◽  
Vol 75 (2) ◽  
pp. 161-167 ◽  
Author(s):  
E. G. Gregorich ◽  
C. M. Monreal ◽  
B. H. Ellert
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Forest Soil ◽  
Half Life ◽  
Light Fraction ◽  
Organic C ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Corn Residue

Total organic C and natural C abundance were measured in a forest soil and a soil under corn (Zea mays L.) to assess management-induced changes in the quantity and initial source of organic matter. The total mass of organic C in the cultivated soil was 19% lower than in the forest soil. It was estimated that after 25 yr of continuous corn, 100 Mg C ha−1 was returned to the soil as residues, of which only 23 Mg ha−1 remained in the soil; 88% of the remaining corn-derived C (C4-derived C) was in the plow layer. About 30% of the soil organic C in the plow layer (0–27 cm) was derived from corn. Assuming first order kinetics, the half-life of C3-derived C in the 0- to 15-cm layer was 13 yr. The half-life of C3-derived C in the 0- to 30-cm layer, which included organic C below the plow layer, was 24 yr. Mineralization of the light fraction (LF) was faster than that of organic matter associated with particle-size fractions. More than 70% of the LF had turned over since the start of corn cropping, and 45% of organic matter in the sand fraction comprised corn residue. The half-life of C3-derived C in the LF was 8 yr. The mineralization of C from native organic matter associated with the coarse silt fraction was the slowest of all particle-size fractions. Key words: Soil organic matter, carbon storage, natural 13C abundance, light fraction, particle-size fractions, mineralization

Cultivation and grassland type effects on light fraction and total organic C and N in a Dark Brown Chernozemic soil

2003 ◽  
Vol 83 (2) ◽  
pp. 145-153 ◽  
Author(s):  
S. S. Malhi ◽  
S. Brandt ◽  
K. S. Gill
Keyword(s):  
Organic Matter ◽  
Soil Samples ◽  
Light Fraction ◽  
Organic C ◽  
Soil Layers ◽  
Chernozemic Soil ◽  
Annual Crops ◽  
Grassland Type ◽  
C And N ◽  
Total Organic C

Light fraction of organic matter is a source of nutrients for plants and a substrate for microbes, while total organic matter is critical for optimum physical conditions and retention of nutrients and other chemicals in soil. The objective of this study was to evaluate the effects of cultivation and grassland type on light fraction and total C and N in a Dark Brown Chernozemic soil. Three paired-sets of soil samples, in five replications, were collected from three cultivated field areas under annual crops [mostly wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.)] and from three adjacent grassland areas. The three sets were a 30-yr-old bromegrass (Bromus inermis Leyss.)/alfalfa (Medicago sativa L.) dominated stand cut annually for hay (Lm) and cultivated area 1 (Ct1), an unbroken native grass stand having no vegetation removed (Ng) and cultivated area 2 (Ct2) and a bromegrass/crested wheatgrass (A gropyron cristatum L. Gaertn.) dominated stand on a land reverted to grassland 60 yr ago having no vegetation removed (Og) and cultivated area 3 (Ct3). Soil samples from the 0- to 5-cm, 5- to 10-cm, 10- to 15-cm, 15- to 20-cm and 20- to 30-cm depths were taken using a 4-cm-diameter coring tube sampler. Total organic C (TOC), total N (TN), light fraction organic C (LFOC) and light fraction N (LFN) in soil were determined and the equivalent mass technique was used to calculate their masses in different soil layers. Total mass (for all soil layers) was less in the cultivated areas compared to the grassland areas by 31 to 43% for TOC, by 84 to 85% for LFOC, by 15 to 34% for TN and by 82 to 84% for LFN. The effect of cultivation was much greater in the surface 5-cm depth compared to deeper soil layers. The proportions of LFOC in TOC and LFN in TN as well as the TOC:TN ratios were lower in the cultivated areas than in the grassland areas, whereas the LFOC:LFN ratios were similar in cultivated and grassland areas. The light fractions of C and N were thus more responsive to change from grassland to cultivation of annual crops compared to the total C and N. Within the grassland areas, the mass of TOC and TN in most of the soil layers was greater in the Lm compared to both Ng and Og areas, while the LFOC and LFN did not show the effect of grassland type. The differences in the mass of both total and light fraction C and N in the cultivated areas were small and generally not significant. The findings suggest that including legume in grassland stands can sequester more organic C and N into the soil even when used for hay production. Key words: Cultivated land, light fraction C and N, native grassland, total organic C and N

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

Carbon sequestration in a Brown Chernozem as affected by tillage and rotation

1995 ◽  
Vol 75 (4) ◽  
pp. 449-458 ◽  
Author(s):  
C. A. Campbell ◽  
B. G. McConkey ◽  
R. P. Zentner ◽  
F. B. Dyck ◽  
F. Selles ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Depth ◽  
Cropping System ◽  
Well Being ◽  
Triticum Aestivum L ◽  
Conventional Tillage ◽  
Organic N ◽  
Organic C ◽  
C And N

Soil organic matter is important because it influences the productivity and physical well-being of soils. Recently, increased attention has focussed on soil organic matter as a possible sink for C02-C. Despite this interest, there is a lack of data for quantifying the effect of tillage on soil organic matter. Between 1981 and 1994, two tillage experiments were conducted at Swift Current, Saskatchewan, on Swinton loam, an Orthic Brown Chernozemic soil. Organic C and N were monitored periodically to quantify the effects of crop rotation [continuous spring wheat (Cont W) (Triticum aestivum L.) vs. fallow–wheat (F-W)] and tillage management [no-tillage (NT) vs. conventional tillage (CT) involving primarily use of a cultivator and rodweeder]. The effect of snow management on soil organic matter was also evaluated in one experiment, but this factor was not significant. Organic matter changes were mainly observed in the 0- to 7.5-cm soil depth. Carbon and N were greater in both concentrations and amounts in Cont W than in F–W; the latter cropping system was employed on this land during the previous 70–80 yr. In the 0- to 7.5-cm depth, the amount of organic matter was only moderately greater in NT than CT in the Cont W systems while in the F-W systems tillage was not significant (P > 0.10). During the 12-yr period, Cont W (average of NT and CT) gained about 2 t ha−1 more C in the top 15 cm of soil than F-W (average of NT and CT), with most of the increase occurring in the first 5 yr. Further, Cont W (NT) gained about 1.5 t ha−1 more C than Cont W (CT), and F-W (NT) gained about 0.5 t ha−1 more than F-W (CT). When a system that was maintained as Cont W (NT) for 9 yr was changed to Cont W (CT) for 3 yr and then summerfallowed (CT) for 1 yr, soil organic matter declined (P < 0.05). Our observations, supported by calculations based on crop residue production, indicated that an increase in organic C, averaging about 0.4–0.5 t ha−1 yr−1, has occurred in the top 15 cm of soil in Cont W (NT) between 1982 and 1993. However, because of uncertainty in our estimated C levels at the start of the experiment, the nature of the rate of C increase (linear or curvilinear) is not known. Key words: Organic C, organic N, no-till, summerfallow

scholarly journals Long term trends in fertility of soils under continuous cultivation and cereal cropping in southern Queensland .VI. Loss of total nitrogen from different particle size and density fractions

Soil Research ◽  
1987 ◽  
Vol 25 (1) ◽  
pp. 83 ◽  
Author(s):  
RC Dalal ◽  
RJ Mayer
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Light Fraction ◽  
Labile Organic Matter ◽  
Total N ◽  
Organic C ◽  
Size Fractions ◽  
Density Fractions ◽  
Organic Matter Fractions ◽  
Sand Size

The dynamics of total N in particle-size and density fractions of six major soils which have been used for cereal cropping for 20-70 years were studied in order to identify the labile organic matter fractions in soil. For virgin soils, no single particle-size was consistently enriched in N as compared with the whole soil. The clay fraction contained the largest proportion (53% overall) of total N. Silt-size and sand-size N fractions accounted for 26% and 21% of total N, respectively. Upon cultivation, the sand-size fraction lost most of its N (as much as 89% in Langlands-Logie soil). However, N losses also occurred from silt-size and clay-size fractions in most soils. Changes in C : N ratios of different particle-size fractions upon cultivation were not consistent in all soils, possibly because of the transfer of organic C and N among these fractions. Therefore, the separation of labile organic matter fractions from the whole soil based upon particle-size may not be successful in all soils. On the other hand, the density fractionation of soil into a light fraction (<2 Mg m-3) containing relatively labile organic matter (76-96% lost upon cultivation) and a heavy fraction (>2 Mg m-3) containing less labile organic matter appears to be more successful in most soils. It is suggested that the cultural practices that enhance the amount of light fraction would increase the rate of nutrient cycling through microbial biomass and may increase the overall availability of nutrients in soil.

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.

scholarly journals Long term trends in fertility of soils under continuous cultivation and cereal cropping in southern Queensland. III. Distribution and kinetics of soil organic carbon in particle size fractions

Soil Research ◽  
1986 ◽  
Vol 24 (2) ◽  
pp. 293 ◽  
Author(s):  
RC Dalal ◽  
RJ Mayer
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Size Fraction ◽  
Organic C ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Clay Size Fraction ◽  
Sand Size

Distribution of soil organic carbon in sand-, silt- and clay-size fractions during cultivation for periods ranging from 20 to 70 years was studied in six major soils used for cereal cropping in southern Queensland. Particle-size fractions were obtained by dispersion in water using cation exchange resin, sieving and sedimentation. In the soils' virgin state no single particle-size fraction was found to be consistently enriched as compared to the whole soil in organic C in all six soils, although the largest proportion (48%) of organic C was in the clay-size fraction; silt and sand-size fractions contained remaining organic C in equal amounts. Upon cultivation, the amounts of organic C declined from all particle-size fractions in most soils, although the loss rates differed considerably among different fractions and from the whole soil. The proportion of the sand-size fraction declined rapidly (from 26% to 12% overall), whereas that of the clay-size fraction increased from 48% to 61% overall. The proportion of silt-size organic C was least affected by cultivation in most soils. It was inferred, therefore, that the sand-size organic matter is rapidly lost from soil, through mineralization as well as disintegration into silt-size and clay-size fractions, and that the clay fraction provides protection for the soil organic matter against microbial and enzymic degradation.

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