Soil organic matter as a function of nitrogen fertilization in crop successions

The interdependence between the C and N cycles is reflected by the levels of soil organic matter (SOM). SOM and organic C levels in water soluble (C-WS) humic acids (C-HA), fulvic acids (C-FA), and humin fractions (C-H) were evaluated through the classic chemical fractionation method in samples of a Rhodic Eutrudox from a randomized blocks experimental design, with split-split-plots using five nitrogen sidedressing levels for corn (0; 60; 120; 180; and 240 kg ha-1 N) as the main treatment, two crop sequences (corn-corn and soybean-corn) as the secondary treatment, and two sampling depths (0 to 0.2 and 0.2 to 0.4 m) as a sub-subtreatment. Nitrogen fertilization did not affect SOM levels, but favored the synthesis of substances in the C-HA fraction. There was a quadratic effect of N rates on the C-WS and C-FA levels in the corn-corn succession. The soybean-corn succession resulted in larger SOM and organic C levels in the C-H fraction.

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A PROCEDURE FOR THE CHARACTERIZATION OF SOIL ORGANIC MATTER

Canadian Journal of Soil Science ◽

10.4141/cjss81-058 ◽

1981 ◽

Vol 61 (3) ◽

pp. 517-519 ◽

Cited By ~ 16

Author(s):

M. SCHNITZER ◽

L. E. LOWE ◽

J. F. DORMAAR ◽

Y. MARTEL

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Fulvic Acids ◽

Total N ◽

Organic C ◽

Soil C ◽

Extraction Separation ◽

C And N ◽

Extractable Soil

In a recent cooperative study, in which four laboratories participated, organic matter in a large number of Canadian soil samples was characterized by relatively simple methods. As result of this work we are proposing a procedure for the extraction, separation and characterization of soil organic matter. The procedure includes determinations of organic C and total N in initial soils, followed by the isolation from the soils of humic and fulvic acids. Total C and N and E4/E6 ratios are then determined in the latter fractions. From these data, proportions of extractable soil-C and soil-N and HA/FA ratios are computed.

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

Soil Research ◽

10.1071/sr18162 ◽

2018 ◽

Vol 56 (8) ◽

pp. 820 ◽

Cited By ~ 2

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.

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Spatial variability of microbial biomass and organic matter labile pools in a haplic planosol soil

Bragantia ◽

10.1590/s0006-87052010000500010 ◽

2010 ◽

Vol 69 (suppl) ◽

pp. 85-95 ◽

Cited By ~ 4

Author(s):

Diego Campana Loureiro ◽

Helvécio De-Polli ◽

Marcos Bacis Ceddia ◽

Adriana Maria de Aquino

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Microbial Biomass ◽

Spatial Variability ◽

Spatial Dependence ◽

Alley Cropping ◽

Cropping System ◽

Water Soluble ◽

Management Systems ◽

C And N

The objective of this work was to study the spatial variability of soil microbial biomass (SMB) and labile soil organic matter pools (labile SOM), under different management systems and plant cover. The experiment was conducted in a Haplic Planosol soil on an Integrated Agroecological Production System (SIPA), in Seropédica, Rio de Janeiro. The evaluated management systems were: alley cropping, pasture, and bush garden, the late one was used as reference area. Three grids of regular spacing of 2.5 x 2.5 meters were used for sampling, consisting of 25 georeferenced points each, where soil samples were taken at 0-10 cm depth. The following labile constituents of soil organic matter were determined: free light fraction (FLF), water soluble C and N, C and N of SMB (SMB-C and SMB-N), and glomalin content. The textural fractions (sand, silt, and clay), pH in water, and chemical attributes (organic C, total N, Ca, Mg, Al, P, K, and CEC-cation exchange capacity) were also determined. The areas of alley cropping and pasture showed spatial dependence to the attributes of SOM. The occurrence of high spatial dependence for the attributes associated to microbial biomass in the alley cropping system (C, FLF, SMB-N and respiration), probably was due to external factors related to management, such as: intensive rotational cropping system, diversity of crops and different inputs of organic matter to soil such as pruning material and organic compost.

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Long – term evalutation of the organic matter balance and its relations to the organic C content in the topsoils in Ústí nad Orlicí district

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis ◽

10.11118/actaun200957020013 ◽

2009 ◽

Vol 57 (2) ◽

pp. 13-24 ◽

Cited By ~ 2

Author(s):

Jiří Dostál ◽

Dana Cerhanová ◽

Lenka Hajzlerová ◽

Jana Martincová ◽

Petra Pospíšilová ◽

...

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Farmyard Manure ◽

Arable Land ◽

Water Soluble ◽

Hot Water ◽

Hydrophobicity Index ◽

Organic C ◽

Time Period ◽

Organic Fertilisers

Organic matter balance in the farms located in Ústí nad Orlicí district has been investigated since 1979. As a result, so called need of organic fertilisation, has been determined and the supply of the organic fertilisers to soils, e.g. farmyard manure, slurries and also straw and green manure has been monitored over the whole time period. About 45 % of the arable land area in the district has been monitored.In addition to the organic matter balance, we determined several soil organic matter characteristics in soil samples (organic C, N and S contents, inert and decomposable C content, hot water soluble C content, hydrophobicity index calculated from the DRIFT spectrometry, available P, K, Ca and Mg contents and pH).The relationships between the organic matter supply with supplemental sources organic fertilisers and all the selected soil organic matter characteristics were statistically significant. Significant correlations were also found for the relationships between the organic matter need and all the selected soil organic matter characteristics.

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

Canadian Journal of Soil Science ◽

10.4141/cjss91-035 ◽

1991 ◽

Vol 71 (3) ◽

pp. 363-376 ◽

Cited By ~ 146

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

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DYNAMICS OF SOIL MICROBIAL BIOMASS AND WATER-SOLUBLE ORGANIC C IN BRETON L AFTER 50 YEARS OF CROPPING TO TWO ROTATIONS

Canadian Journal of Soil Science ◽

10.4141/cjss86-001 ◽

1986 ◽

Vol 66 (1) ◽

pp. 1-19 ◽

Cited By ~ 371

Author(s):

W. B. McGILL ◽

K. R. CANNON ◽

J. A. ROBERTSON ◽

F. D. COOK

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Environmental Conditions ◽

Management Practices ◽

Water Soluble ◽

Turnover Rates ◽

Organic Matter Quality ◽

Organic C ◽

Microbial N

Amounts and turnover rates of biomass and water-soluble organic C (WSOC) were measured at the Breton plots where records of long-term management of a Gray Luvisolic soil are available. Plots (control, manure, and NPKS) which had been cropped to either a wheat-fallow or a wheat-oats-barley-forage-forage rotation for 50 yr were sampled 13 times during 1981 and 1982. Biomass C and flush of microbial N were measured using the chloroform fumigation technique. Long-term crop yields were used to derive C supply to the plots. Regression analyses were used to relate seasonal fluctuations in environmental conditions to biomass and WSOC dynamics. Reinoculation with soil was unnecessary but Lysobacter sp. formed a greater proportion of isolates following incubation of fumigated soil than of unfumigated samples. Reinoculation with Lysobacter sp. is suggested to provide a more standardized biological assay. The 5-yr rotation contained 38% more N but 117% more microbial N than did the 2-yr rotation, and manured treatments contained twice as much microbial N as did NPKS or control plots. A management effect on soil organic matter quality is indicated. Averge turnover rates of biomass were 0.2–3.9 yr−1; being 1.5–2 times faster in the 2-yr rotation than in the 5-yr rotation. Replenishment of the WSOC component would have to occur 26–39 times yr−1 to supply microbial turnover. Most of the biomass must be dormant because annual C inputs are two orders of magnitude less than maintenance energy requirements. Seasonal variations in biomass were most consistently related to losses during desiccation and regrowth upon moistening. Regrowth appears to be at the expense of native soil organic matter. Management practices and environmental conditions therefore affect amount of organic matter by controlling both input of C and biomass turnover. Key words: Crop rotations, Luvisol, organic matter, biomass, soluble C, Breton plots

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

Canadian Journal of Soil Science ◽

10.4141/cjss95-065 ◽

1995 ◽

Vol 75 (4) ◽

pp. 449-458 ◽

Cited By ~ 71

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

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SOIL ORGANIC MATTER CHARACTERISTICS AFTER LONG-TERM CROPPING TO VARIOUS SPRING WHEAT ROTATIONS

Canadian Journal of Soil Science ◽

10.4141/cjss87-081 ◽

1987 ◽

Vol 67 (4) ◽

pp. 845-856 ◽

Cited By ~ 99

Author(s):

H. H. JANZEN

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Soil Fertility ◽

Crop Rotation ◽

Spring Wheat ◽

N Mineralization ◽

Soil Layer ◽

Organic C ◽

C And N

Soil from a long-term crop rotation study conducted at Lethbridge, Alberta was analyzed to determine the influence of various spring wheat rotations with and without perennial forages on total and mineralizable soil organic matter contents. Crop rotations considered included: continuous wheat (W), fallow-wheat (FW), fallow-wheat-wheat (FWW), and fallow-wheat-wheat-forage-forage-forage (FWWAAA) in which the forage was a mixture of alfalfa and crested wheat grass. The organic C and N contents of soil after 33 yr of cropping were highest in treatments W and FWWAAA, and decreased with increasing frequency of fallow in the rotation. The inclusion of the perennial forage in the rotation did not increase organic C and N levels above those observed in the continuous wheat treatment (W). Differences in levels of mineralizable organic matter among treatments, as measured in laboratory incubations, were much greater than differences in total organic matter content among treatments. In the surface soil layer (0–15 cm), N mineralization was significantly higher in treatment W than in treatments FWW and FWWAAA, and was more than twice that observed in treatment FW. In the subsurface soil layer (15–30 cm), N mineralization was greatest in treatment FWWAAA when sampled just after the plowdown of forage. Effects of crop rotation on C mineralization were similar to those observed for N. Levels of mineralized organic matter were closely related to levels of "light fraction" material (specific gravity < 1.59 g cm−3), which is believed to consist primarily of incompletely decomposed organic matter of plant origin. Differences in amounts of mineralizable organic matter among treatments were attributed to varying frequencies and patterns of crop residue additions. The pronounced effects of crop rotation on the distribution of organic matter among labile and humified organic matter will have a strong impact on soil fertility and may need to be taken into consideration in the development of fertilizer recommendations. It was concluded that inclusion of perennial forages in spring wheat rotations for the purpose of enhancing soil fertility and organic matter levels was not justified under semiarid conditions. Key words: Carbon, nitrogen, mineralization

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SOIL ORGANIC MATTER FRACTIONS UNDER SECOND-ROTATION EUCALYPTUS PLANTATIONS IN EASTERN RIO GRANDE DO SUL

Revista Árvore ◽

10.1590/1806-90882017000100007 ◽

2017 ◽

Vol 41 (1) ◽

Cited By ~ 3

Author(s):

Emanuelle Mercês Barros Soares ◽

Ivo Ribeiro Silva ◽

Nairam Félix Barros ◽

Rafael Silva Teixeira ◽

Sebastião Fonseca ◽

...

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Sandy Soil ◽

Soil Layer ◽

Rio Grande ◽

Rio Grande Do Sul ◽

Organic C ◽

C Stocks ◽

Eucalyptus Plantations ◽

C And N

ABSTRACT The aim of the present study was to evaluate the effect of eucalyptus plantations on total organic C (TOC) and total N (TN) stocks as well as the C and N in the fulvic acid (FA), humic acid (HA), humin (HU), light organic matter (LOM) and microbial biomass (MB) fractions in soils with different textures in the eastern part of the state of Rio Grande do Sul, Brazil. Soil samples were collected from the 0-10-cm, 10-20-cm, 20-40-cm, 40-60-cm and 60-100-cm soil layers in a completely randomized experimental design with subdivided plots. Under the eucalyptus plantation, clay loam soil presented lower HA, HU and MB C stocks in the 0-100-cm soil layer compared to reference vegetation, whereas sandy soil presented higher and C and N in HA and LOM as well as C in MB. The observed increase in TOC in eucalyptus plantations was more pronounced in the surface soil layer (0-10 cm), i.e., approximately 150% higher than under native vegetation, which was probably due to the high contribution of the eucalyptus litter. Differences in C and N stocks in soil organic matter (SOM) fractions between eucalyptus plantations and areas with reference vegetation were more pronounced in sandy soil, showing the capacity of the clay fraction to protect SOM.

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Organic acids promote phosphorus release from Mollisols with different organic matter contents

Soil and Water Research ◽

10.17221/140/2019-swr ◽

2020 ◽

Vol 16 (No. 1) ◽

pp. 59-66

Author(s):

Xiaoyan Yang ◽

Chuandong Zhang ◽

Haiping Gu ◽

Xiangwei Chen ◽

Erhui Guo

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Organic Acids ◽

Inorganic Phosphorus ◽

Phosphorus Release ◽

Chemical Fractionation ◽

P Availability ◽

Inorganic P ◽

Soil P ◽

Fractionation Method

Organic acids could improve the phosphorus (P) availability through enhancing the release of inorganic phosphorus (Pi) in the soil. However, the effects of organic acids on the Pi release are still poorly understood, especially from soils with different organic matter contents. Here, a biochemically produced humic acid and P fertiliser were added to the soil to modify the content of the soil organic matter (SOM) and soil P, respectively. And then the soil samples were incubated at 25 °C for 30 days. The release of Pi fractions (such as H2O-Pi, NaHCO3-Pi, NaOH-Pi, HCl-Pi, and Residual-P) from the soils with different organic matter contents in the presence of citric, oxalic, and malic acids was evaluated using a sequential chemical fractionation method. The results showed that the release of the NaHCO3-Pi, NaOH-Pi, and HCl-Pi fractions also showed a decreasing trend with an increasing content of soil organic matter, and more NaOH-Pi than the other Pi fractions was generally released in the presence of organic acids. Considering the types of organic acids, oxalic acid and malic acid most effectively and least effectively released Pi, respectively. The path analysis indicated that the NaOH-Pi release had the highest direct and indirect effects on the total inorganic P (TPi) release. NaOH-Pi was, therefore, the most effective source of Pi in the Mollisols.

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