Assessing the impact of land-use change on soil C sequestration in agricultural soils by means of organic matter fractionation and stable C isotopes

Soil properties are strongly influenced by the composition of the surrounding vegetation. We investigated soil properties of three ecosystems; a coniferous forest, a deciduous forest and an agricultural grassland, to determine the impact of land use change on soil properties. Disturbances such as deforestation followed by cultivation can severely alter soil properties, including losses of soil carbon. We collected nine 40 cm cores from three ecosystem types on the Roebuck Farm, north of Perth Village, Ontario, Canada. Dominant species in each ecosystem included hemlock and white pine in the coniferous forest; sugar maple, birch and beech in the deciduous forest; grasses, legumes and herbs in the grassland. Soil pH varied little between the three ecosystems and over depth. Soils under grassland vegetation had the highest bulk density, especially near the surface. The forest sites showed higher cation exchange capacity and soil moisture than the grassland; these differences largely resulted from higher organic matter levels in the surface forest soils. Vertical distribution of organic matter varied greatly amongst the three ecosystems. In the forest, more of the organic matter was located near the surface, while in the grassland organic matter concentrations varied little with depth. The results suggest that changes in land cover and land use alters litter inputs and nutrient cycling rates, modifying soil physical and chemical properties. Our results further suggest that conversion of forest into agricultural land in this area can lead to a decline in soil carbon storage.

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Economic Feasibility of Soil C Sequestration in U.S. Agricultural Soils

Agriculture Practices and Policies for Carbon Sequestration in Soil ◽

10.1201/9781420032291.ch32 ◽

2002 ◽

Cited By ~ 1

Author(s):

M Sperow ◽

R House ◽

Keith Paustian ◽

M Peters

Keyword(s):

Agricultural Soils ◽

C Sequestration ◽

Economic Feasibility ◽

Soil C ◽

Soil C Sequestration

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Economic Feasibility of Soil C Sequestration in U.S. Agricultural Soils

Agricultural Practices and Policies for Carbon Sequestration in Soil ◽

10.1201/9781420032291-36 ◽

2016 ◽

pp. 361-372

Keyword(s):

Agricultural Soils ◽

C Sequestration ◽

Economic Feasibility ◽

Soil C ◽

Soil C Sequestration

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Quantifying total and labile pools of soil organic carbon in cultivated and uncultivated soils in eastern India

Soil Research ◽

10.1071/sr17188 ◽

2018 ◽

Vol 56 (4) ◽

pp. 413 ◽

Cited By ~ 2

Author(s):

Kumari Priyanka ◽

Anshumali

Keyword(s):

Land Use ◽

Function Analysis ◽

Land Use Changes ◽

C Sequestration ◽

Sensitivity Index ◽

Organic C ◽

Soil C ◽

C Pools ◽

The Impact ◽

Land Use Practices

Loss of labile carbon (C) fractions yields information about the impact of land-use changes on sources of C inputs, pathways of C losses and mechanisms of soil C sequestration. This study dealt with the total organic C (TOC) and labile C pools in 40 surface soil samples (0–15 cm) collected from four land-use practices: uncultivated sites and rice–wheat, maize–wheat and sugarcane agro-ecosystems. Uncultivated soils had a higher total C pool than croplands. The soil inorganic C concentrations were in the range of 0.7–1.4 g kg–1 under different land-use practices. Strong correlations were found between TOC and all organic C pools, except water-extractable organic C and mineralisable C. The sensitivity index indicated that soil organic C pools were susceptible to changes in land-use practices. Discriminant function analysis showed that the nine soil variables could distinguish the maize–wheat and rice–wheat systems from uncultivated and sugarcane systems. Finally, we recommend crop rotation practices whereby planting sugarcane replenishes TOC content in soils.

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Millennia-old carbon fluxes from degraded tropical peatland soils

10.5194/egusphere-egu2020-21851 ◽

2020 ◽

Author(s):

Stephanie Evers ◽

Thomas Smith ◽

Mark Garnett ◽

Selvakumar Dhandipani ◽

Massimo Lupascu

Keyword(s):

Land Use ◽

Organic Matter ◽

Land Use Change ◽

Ecosystem Respiration ◽

Critical Element ◽

Tropical Peatland ◽

Agricultural Conversion ◽

C Cycling ◽

The Impact ◽

Global Carbon

Assessing the flux of carbon (C) from terrestrial ecosystems to the atmosphere represents a critical element of global carbon budgeting. In tropical peatlands this has been a fundamental part of assessing the impact of land use change on an ecosystem that represents a significant global carbon store, with peat accumulation being often many meters deep. These systems have formed over thousands of years as a function of incomplete decomposition of organic matter from water-logged swamp forests. However, intact tropical peat swamp forests (PSFs) are under increasing threat from agricultural conversion, deforestation, drainage practices and fires. The resultant alteration of the peat soil results in peat oxidation, increased rates of organic matter decomposition and greenhouse gas (GHG) emissions. Consequently, these peats are reverting from C stores to sources.Radiocarbon (14C) abundance can be used to assess C cycling rates in varied ecosystems and identify rapid or slow C turnover rates from years to centuries, as well as shifts in cycling rates &#8211; for example with land use or hydrological alteration. Within intact peatlands, deep peats generally contain an increasing abundance of 14C depleted content due to radioactive decay, conversely, shallower peats are more abundant in recently produced organic litter enriched with &#8220;Bomb C&#8221;; derived from nuclear testing in the 1960s. Similarly, root derived organic matter and the associated root respiration (autotrophic respiration) also have signatures resembling recent atmospheres, whereas microbial respiration of soil organic matter (heterotrophic respiration) will resemble the mean age of the soil carbon being utilised by the microbial community, and as such can be a tracer for sources of carbon being decomposed.&#160;Yet while an increasing body of knowledge exists on tropical peatland carbon flux rates or net ecosystem respiration in association with land-use change, these approaches fail to delineate the sources of carbon being used within the soil profile and thus fully address questions linked to changing carbon cycling rates with land use change.Here we provide what we believe to be the first data on 14CO2 fluxes from tropical peatland soils in relation to varying land use classes with the aim of determining if peats which were previously long-terms C stores are being utilised within short, fast C cycles and thus contributing to modern GHG budgets. CO2 flux rates were measured using soil chambers and emitted CO2 was subsequently trapped on a zeolite molecular sieve cartridge. An aliquot of the recovered CO2 was graphitised and analysed for 14C by accelerator mass spectrometry. Associated soil age profiles were also determined.Results indicate significant fluxes of multi-millennia old carbon from peatlands under altered land use classes and clear evidence for a shift to C cycling speed, with previously long-term stored C contributing to modern C budgets. Result highlight the instability of the peat profile under altered land-use classes and minimal to no contribution of modern C from recently produced organic matter to these carbon budgets. Findings clearly indicate the unsustainability of these agricultural practices and the need for burn- and drain-free land-use strategies.

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Land Use Affects the Soil C Sequestration in Alpine Environment, NE Italy

Forests ◽

10.3390/f8060197 ◽

2017 ◽

Vol 8 (6) ◽

pp. 197 ◽

Cited By ~ 9

Author(s):

Diego Pizzeghello ◽

Ornella Francioso ◽

Giuseppe Concheri ◽

Adele Muscolo ◽

Serenella Nardi

Keyword(s):

Land Use ◽

C Sequestration ◽

Alpine Environment ◽

Soil C ◽

Ne Italy ◽

Soil C Sequestration

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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 ◽

10.1071/sr04044 ◽

2005 ◽

Vol 43 (1) ◽

pp. 13 ◽

Cited By ~ 40

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.

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The impact of fertilization regime and land use change on the SOM after 60 years of maize cropping

10.5194/egusphere-egu2020-19887 ◽

2020 ◽

Author(s):

Zoltán Szalai ◽

Ujházy Noémi ◽

Anna Vancsik ◽

Azer Hallabi ◽

Gergely Jakab ◽

...

Keyword(s):

Land Use ◽

Organic Matter ◽

Land Use Change ◽

Microbial Diversity ◽

Arable Land ◽

Soil Samples ◽

Size Exclusion ◽

Rrna Gene ◽

Arable Soils ◽

The Impact

The top metre of the soil is one of the largest terrestrial carbon reservoirs. More than 50% of the soil carbon is stored as soil organic matter (SOM). Several papers report about the SOM losses due to tillage and land-use change. On the other hand, a huge amount of papers focus on the environmental potential of various min-till, no-till and other techniques for regenerative agriculture. The change of the fertilization regime also has an influence on SOM so it also can influence the humus status of the soils. This presentation focuses on the effects of different kinds of fertilization and abandonment of arable lands on the quantity and quality of the SOM. The present study is based on Martonv&#225;s&#225;r Experimental Station (Hungary) which was established in 1958. The research focused on maize monoculture with the following treatments: (a) no fertilization, (b) NPK, (c) NPK with manure addition. The soil of the plots is Chernozem. Two controls were selected: (a) a natural Grassland and a secondary grassland. The secondary grassland was an arable land until 1990. Five repetitions of soil samples were taken from each plot and times. Soils were fractionated to silt and clay associated OM (s+c), aggregate associated OM (S+A), dissolved organic matter (DOM) and particulate organic matter (POM) according to Zimmermann&#8217;s method (4). Quality parameters of the DOM were studied by CN analyser, UV-Vis spectrometer, spectrofluorometer, zetasizer and size exclusion chromatograph. Solid SOM fractions were studied by CHNS analyser, ATR-FTIR and DRIFT FTIR. The V3-V4 regions of the 16S rRNA gene obtained from the soil samples were sequenced on the Illuma platform for the description of microbial diversity. Twenty years were enough to restore the natural SOM content of the soils (land-use change from arable land to grassland). Labile fractions of the SOM were higher in case of secondary than the primary grasslands. We have found differences in weight ratios of SOM fractions between fertilization regimes, as well. The proportion of microbial contribution to SOM were higher in the arable soils than the grasslands based on the C:N ratios of the SOM. However, the predominance of phyla Proteobacteria, Acidobacteria, Bacteriodetes, Actinobacteria and Verrucomicrobia in all studied soils, microbial diversity is generally higher in the grasslands than in the arable plots. The DOM of different fertilization regimes and land uses have shown the most characteristic differences. The difference between arable plots (with various fertilization regimes) and grasslands can be characterized by humic substances (HS) with higher condensation degree and molecular mass. The application of manure has result same proportion of peptide-like components and HS with lower molecular as the DOM of grassland soils. The microbial diversity of abandoned arable land remained similar to that of the arable lands over twenty years. The major part of the growth of SOM occurred in the labile fractions. The change of the fertilization regime also has limited potential to grow a total mass of SOM. Support of the GINOP 2.3.2-15-2016-00056 and National Research, Development and Innovation Office under contracts K123953 are gratefully acknowledged.

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Land Use Change Effects on Soil Quality in Prince Edward County, ON

Inquiry@Queen's Undergraduate Research Conference Proceedings ◽

10.24908/iqurcp.9042 ◽

2016 ◽

Author(s):

Elizabeta Kjikjerkovska

Keyword(s):

Land Use ◽

Organic Matter ◽

Land Use Change ◽

Soil Quality ◽

Perennial Grass ◽

Chemical Properties ◽

Total Carbon ◽

Soil C ◽

Prince Edward County ◽

Productivity Potential

Soils play a key role in Earth System function. When original vegetation cover is converted to cultivated land, soils often become degraded and lose their productivity potential. We examined the effects of land-use change on a clay/clay loam soil on a farm in Ameliasburg on the northern part of Prince Edward County. Three cover types were examined: perennial sod (for lawns), perennial switchgrass (potential bioengery crop) and undisturbed forest. For each soil type, cores to a depth of 40cm were collected along three random 30m transects (at 8, 16 and 24m), then divided into 10cm increments and combined along one transect according to depth. Soil quality was assessed by analyzing various soil physical and chemical properties. Bulk density was almost two-fold higher (1.5 vs. 0.82 g/cm3) in both grass systems compared to the forest, but only in the 0-10cm layer, likely due to surface compaction associated with land management. Soil pH was slightly lower in the forest compared to the switchgrass field. The sod and switchgrass fields showed losses of ~33% and ~53% organic matter, respectively in contrast to the forested area. The largest differences for organic matter and total carbon were in the top 20cm. Soil C: N ratios were highest for the forested site and lowest for the sod field. Although perennial grass systems often enhance soil quality compared to extensively tilled sites, it appears that long-term (10y) sod production has led to a decline in some, but not all, soil quality measures, particularly soil organic matter and carbon content.

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Effect of deforestation and subsequent land use management on soil carbon stocks in the South American Chaco

SOIL ◽

10.5194/soil-4-251-2018 ◽

2018 ◽

Vol 4 (4) ◽

pp. 251-257 ◽

Cited By ~ 5

Author(s):

Natalia Andrea Osinaga ◽

Carina Rosa Álvarez ◽

Miguel Angel Taboada

Keyword(s):

Land Use ◽

Land Use Change ◽

Warm Season ◽

Continuous Cropping ◽

Soil Organic C ◽

Organic C ◽

Soil C ◽

C Stocks ◽

C Stock ◽

The Impact

Abstract. The subhumid Chaco region of Argentina, originally covered by dry sclerophyll forest, has been subjected to clearing since the end of the 1970s and replacement of the forest by no-till farming. Land use changes produced a decrease in aboveground carbon (C) stored in forests, but little is known about the impact on soil organic C stocks. The aim of this study was to evaluate soil C stocks and C fractions up to 1 m depth in soils under different land use: <10-year continuous cropping, >20-year continuous cropping, warm-season grass pasture and native forest in 32 sites distributed over the Chaco region. The organic C stock content up to 1 m depth expressed as equivalent mass varied as follows: forest (119.3 Mg ha−1) > pasture (87.9 Mg ha−1) > continuous cropping (71.9 and 77.3 Mg ha−1), with no impact of the number of years under cropping. The coarse particle fraction (2000–212 µm) at 0–5 and 5–20 cm depth layers was the most sensitive organic carbon fraction to land use change. Resistant carbon (<53 µm) was the main organic matter fraction in all sample categories except in the forest. Organic C stock, its quality and its distribution in the profile were responsive to land use change. The conversion of the Chaco forest to crops was associated with a decrease of organic C stock up to 1 m depth and with the decrease of the labile fraction. The permanent pastures of warm-season grasses allowed higher C stocks to be sustained than cropping systems and so could be considered a sustainable land use system in terms of soil C preservation. As soil organic C losses were not restricted to the first few centimetres of the soil, the development of models that would allow the estimation of soil organic C changes in depth would be useful to evaluate the impact of land use change on C stocks with greater precision.

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