Monitoring Grassland Management Effects on Soil Organic Carbon—A Matter of Scale

Introduction of temporary grasslands into cropping cycles could be a sustainable management practice leading to increased soil organic carbon (SOC) to contribute to climate change adaption and mitigation. To investigate the impact of temporary grassland management practices on SOC storage of croplands, we used a spatially resolved sampling approach combined with geostatistical analyses across an agricultural experiment. The experiment included blocks (0.4- to 3-ha blocks) of continuous grassland, continuous cropping and temporary grasslands with different durations and N-fertilizations on a 23-ha site in western France. We measured changes in SOC storage over this 9-year experiment on loamy soil and investigated physicochemical soil parameters. In the soil profiles (0–90 cm), SOC stocks ranged from 82.7 to 98.5 t ha−1 in 2005 and from 81.3 to 103.9 t ha−1 in 2014. On 0.4-ha blocks, the continuous grassland increased SOC in the soil profile with highest gains in the first 30 cm, while losses were recorded under continuous cropping. Where temporary grasslands were introduced into cropping cycles, SOC stocks were maintained. These observations were only partly confirmed when changing the scale of observation to 3-ha blocks. At the 3-ha scale, most grassland treatments exhibited both gains and losses of SOC, which could be partly related to soil physicochemical properties. Overall, our data suggest that both management practices and soil characteristics determine if carbon will accumulate in SOC pools. For detailed understanding of SOC changes, a combination of measurements at different scales is necessary.

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Effect of cropping practices on soil organic carbon: evidence from long-term field experiments in Victoria, Australia

Soil Research ◽

10.1071/sr14227 ◽

2015 ◽

Vol 53 (6) ◽

pp. 636 ◽

Cited By ~ 16

Author(s):

Fiona Robertson ◽

Roger Armstrong ◽

Debra Partington ◽

Roger Perris ◽

Ivanah Oliver ◽

...

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Management Practices ◽

Field Experiments ◽

Residue Management ◽

Continuous Cropping ◽

Zero Tillage ◽

Stubble Retention ◽

Soc Stocks

Despite considerable research, predicting how soil organic carbon (SOC) in grain production systems will respond to conservation management practices, such as reduced tillage, residue retention and alternative rotations, remains difficult because of the slowness of change and apparent site specificity of the effects. We compared SOC stocks (equivalent soil mass to ~0–0.3 m depth) under various tillage, residue management and rotation treatments in three long-term (12-, 28- and 94-year-old) field experiments in two contrasting environments (Mallee and Wimmera regions). Our hypotheses were that SOC stocks are increased by: (1) minimum tillage rather than traditional tillage; (2) continuous cropping, rather than crop–fallow rotations; and (3) phases of crop or pasture legumes in rotations, relative to continuous cropping with cereals. We found that zero tillage and stubble retention increased SOC in some circumstances (by up to 1.5 Mg C ha–1, or 8%) but not in others. Inclusion of bare fallow in rotations reduced SOC (by 1.4–2.4 Mg C ha–1, or 8–12%) compared with continuous cropping. Including a pulse crop (field pea, where the grain was harvested) in rotations also increased SOC in some instances (by ~6–8 Mg C ha–1, or 29–35%) but not in others. Similarly, leguminous pasture (medic or lucerne) phases in rotations either increased SOC (by 3.5 Mg C ha–1, or 21%) or had no significant effect compared with continuous wheat. Inclusion of a vetch green manure or unfertilised oat pasture in the rotation did not significantly increase SOC compared with continuous wheat. The responses in SOC to these management treatments were likely to be due, in part, to differences in nitrogen and water availability (and their effects on carbon inputs and decomposition) and, in part, to other, unidentified, interactions. We conclude that the management practices examined in the present study may not reliably increase SOC on their own, but that significant increases in SOC are possible under some circumstances through the long-term use of multiple practices, such as stubble retention + zero tillage + legume N input + elimination of fallow. The circumstances under which increases in SOC can be achieved require further investigation.

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Stocks, composition and vulnerability to loss of soil organic carbon predicted using mid-infrared spectroscopy

Soil Research ◽

10.1071/sr17221 ◽

2018 ◽

Vol 56 (5) ◽

pp. 468 ◽

Cited By ~ 10

Author(s):

J. A. Baldock ◽

M. H. Beare ◽

D. Curtin ◽

B. Hawke

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Management Practices ◽

Cost Effective ◽

Agricultural Management ◽

Least Squares Regression ◽

Mid Infrared ◽

13C Nuclear Magnetic Resonance ◽

The Impact ◽

Soc Stocks

Developing a routine and cost effective capability for measuring soil organic carbon (SOC) content and composition will allow identification of land management practices with a potential to maintain or enhance SOC stocks. Coupling SOC content data and mid-infrared (MIR) spectra through the application of partial least-squares regression (PLSR) analyses has been used to develop such a prediction capability. The objective of this study was to determine whether MIR/PLSR analyses provide accurate estimates of the content and composition of SOC that can be used to quantify SOC stocks and its potential vulnerability to loss. Soil was collected from a field trial incorporating a range of land use (pasture, arable cropping and bare fallow) and tillage (intensive, minimum and no tillage) treatments over a nine-year period. The SOC content was measured by dry combustion analysis. Particulate organic carbon was separated from other forms of carbon on the basis of particle size (SOC in the >50 µm fraction). Resistant organic carbon was quantified using solid-state 13C nuclear magnetic resonance. The MIR/PLSR algorithms were successfully developed to predict the natural logarithms of the contents of SOC and POC in the collected soils. With initial calibration, a single MIR analysis could be used in conjunction with PLSR algorithms to predict the content of SOC and its allocation to component fractions. The MIR/PLSR predicted SOC contents provided reliable estimates of the impact of agricultural management on the 0–25-cm SOC stocks, as well as an indication of the vulnerability of SOC to loss. Development of this capability will facilitate the rapid and cost effective collection of SOC content data for detecting the impact of agricultural management treatments on SOC stocks, composition and potential vulnerability to change.

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Organic carbon and associated soil properties of a red earth after 10 years of rotation under different stubble and tillage practices

Soil Research ◽

10.1071/sr9920071 ◽

1992 ◽

Vol 30 (1) ◽

pp. 71 ◽

Cited By ~ 76

Author(s):

KY Chan ◽

WP Roberts ◽

DP Heenan

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Management Practices ◽

Management Practice ◽

Wagga Wagga ◽

Continuous Cropping ◽

Carbon Level ◽

Significant Difference ◽

Red Earth ◽

Stubble Burning

Differences in soil organic carbon level as a result of different tillage and stubble management practices under continuous cropping were studied in a 10 years old wheat/lupin rotation experiment on a red earth at Wagga Wagga, New South Wales. Stubble burning and tillage had a similar impact in reducing the total amounts of organic carbon in the top 0-2 m of soil. There was no significant difference between the conventional cultivation (3 cultivations) and reduced cultivation (1 cultivation) systems. A 31% difference in organic carbon in the top 0.1 m (2.42% v. 1.68%) was found between the extreme management practices, i.e. direct drill /stubble retained treatment and the conventional/stubble burnt treatment. These results highlight the important effect of management practice on soil organic carbon level under continuous cropping. Tillage had the additional effect of changing the distribution of organic carbon resulting in higher level in the 0.10-0.15 m layer. The reduction in organic carbon was accompanied by significant losses in total nitrogen, exchangeable calcium and magnesim, as well as reduction in biological activity and aggregate stability. Loss of 1% organic carbon resulted in a loss of 2-97 cmole(+) kg soil-1 of negative charge. However, C/N ratio remained constant at 12-1 under different tillage and stubble treatments. Finally, while stubble burning resulted in pH increase, tillage led to a significant reduction in soil pH (5.38 to 4.98) in the 0 - 0.05 m layer due to increased exchangeable A1 brought to the soil surface as a result of an inversion action.

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Influence of agricultural management on soil organic carbon: A compendium and assessment of Canadian studies

Canadian Journal of Soil Science ◽

10.4141/s03-009 ◽

2003 ◽

Vol 83 (4) ◽

pp. 363-380 ◽

Cited By ~ 194

Author(s):

A. J. VandenBygaart ◽

E. G. Gregorich ◽

D. A. Angers

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Management Practices ◽

Agricultural Management ◽

Organic Fertilizers ◽

Published Data ◽

Native Land ◽

Soc Stocks ◽

Long Term Studies

To fulfill commitments under the Kyoto Protocol, Canada is required to provide verifiable estimates and uncertainties for soil organic carbon (SOC) stocks, and for changes in those stocks over time. Estimates and uncertainties for agricultural soils can be derived from long-term studies that have measured differences in SOC between different management practices. We compiled published data from long-term studies in Canada to assess the effect of agricultural management on SOC. A total of 62 studies were compiled, in which the difference in SOC was determined for conversion from native land to cropland, and for different tillage, crop rotation and fertilizer management practices. There was a loss of 24 ± 6% of the SOC after native land was converted to agricultural land. No-till (NT) increased the storage of SOC in western Canada by 2.9 ± 1.3 Mg ha-1; however, in eastern Canada conversion to NT did not increase SOC. In general, the potential to store SOC when NT was adopted decreased with increasing background levels of SOC. Using no-tillage, reducing summer fallow, including hay in rotation with wheat (Triticum aestivum L.), plowing green manures into the soil, and applying N and organic fertilizers were the practices that tended to show the most consistent in creases in SOC storage. By relating treatment SOC levels to those in the control treatments, SOC stock change factors and their levels of uncertainty were derived for use in empirical models, such as the United Nations Intergovernmental Panel on Climate Change (IPCC). Guidelines model for C stock changes. However, we must be careful when attempting to extrapolate research plot data to farmers’ fields since the history of soil and crop management has a significant influence on existing and future SOC stocks. Key words: C sequestration, tillage, crop rotations, fertilizer, cropping intensity, Canada

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Qualitative and quantitative response of soil organic carbon to 40 years of crop residue incorporation under contrasting nitrogen fertilisation regimes

Soil Research ◽

10.1071/sr15377 ◽

2017 ◽

Vol 55 (1) ◽

pp. 1 ◽

Cited By ~ 19

Author(s):

Christopher Poeplau ◽

Lisa Reiter ◽

Antonio Berti ◽

Thomas Kätterer

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Crop Residue ◽

Crop Residues ◽

Management Practice ◽

Soil Layer ◽

Clay Fraction ◽

Residue Incorporation ◽

Crop Residue Incorporation ◽

Soc Stocks

Crop residue incorporation (RI) is recommended to increase soil organic carbon (SOC) stocks. However, the positive effect on SOC is often reported to be relatively low and alternative use of crop residues, e.g. as a bioenergy source, may be more climate smart. In this context, it is important to understand: (i) the response of SOC stocks to long-term crop residue incorporation; and (ii) the qualitative SOC change, in order to judge the sustainability of this measure. We investigated the effect of 40 years of RI combined with five different nitrogen (N) fertilisation levels on SOC stocks and five SOC fractions differing in turnover times on a clay loam soil in Padua, Italy. The average increase in SOC stock in the 0–30cm soil layer was 3.1Mgha–1 or 6.8%, with no difference between N fertilisation rates. Retention coefficients of residues did not exceed 4% and decreased significantly with increasing N rate (R2=0.49). The effect of RI was higher after 20 years (4.6Mgha–1) than after 40 years, indicating that a new equilibrium has been reached and no further gains in SOC can be expected. Most (92%) of the total SOC was stored in the silt and clay fraction and 93% of the accumulated carbon was also found in this fraction, showing the importance of fine mineral particles for SOC storage, stabilisation and sequestration in arable soils. No change was detected in more labile fractions, indicating complete turnover of the annual residue-derived C in these fractions under a warm humid climate and in a highly base-saturated soil. The applied fractionation was thus useful to elucidate drivers and mechanisms of SOC formation and stabilisation. We conclude that residue incorporation is not a significant management practice affecting soil C storage in warm temperate climatic regions.

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The resilience of soil organic carbon stocks under contrasting hill country pasture management practices

NZGA: Research and Practice Series ◽

10.33584/rps.17.2021.3449 ◽

2021 ◽

Vol 17 ◽

Author(s):

Alec Mackay ◽

Ronaldo Eduardo Vibart ◽

Catherine McKenzie ◽

Brian Devantier ◽

Emma Noakes

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Management Practices ◽

Pasture Management ◽

Single Superphosphate ◽

Hill Country ◽

Soil Organic Carbon Stocks ◽

Environmental Goals ◽

The Stability ◽

Soc Stocks

In 2020 we measured the stability of soil organic carbon (SOC) concentrations and stocks under contrasting hill country pasture regimes, by sampling three slope classes and three aspect locations on each of three farmlets of a long-term phosphorus fertiliser and sheep grazing experiment. The farmlets included no annual phosphorus (NF), 125 kg of single superphosphate/ha (LF), or 375 kg superphosphate/ha (HF) that has been applied on an annual basis since 1980. Results from the 2020 sampling event were added to previous results reported from soil samples collected in 2003 and 2014. The SOC concentrations in the topsoil (0-75 mm depth), ranging from 4.23 to 5.99% across all slopes and aspects of the farmlets, fell within the normal range (≥3.5 and <7.0%) required for sustaining production and environmental goals. A trend was shown for greater SOC stocks in the topsoil in the HF farmlet (34.0 Mg/ ha) compared with the other two farmlets (31.6 Mg/ha), but this trend was not evident in the deeper soil layers (75-150, 150-300, 0-300 mm). Under the current conditions, topographical features such as slope and aspect had a more profound influence on SOC stocks than management history.

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Soil organic carbon in cropping and pasture systems of Victoria, Australia

Soil Research ◽

10.1071/sr15008 ◽

2016 ◽

Vol 54 (1) ◽

pp. 64 ◽

Cited By ~ 10

Author(s):

Fiona Robertson ◽

Doug Crawford ◽

Debra Partington ◽

Ivanah Oliver ◽

David Rees ◽

...

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Soil Properties ◽

Environmental Conditions ◽

Management Practices ◽

Annual Rainfall ◽

Continuous Cropping ◽

C Stocks ◽

Wide Range ◽

Soc Stock

Increasing soil organic carbon (SOC) storage in agricultural soils through changes to management may help to mitigate rising greenhouse gas emissions and sustain agricultural productivity and environmental conditions. However, in order to improve assessment of the potential for increasing SOC storage in the agricultural lands of Victoria, Australia, further information is required on current SOC levels and how they are related to environmental conditions, soil properties and agricultural management. Therefore, we measured stocks of SOC at 615 sites in pasture and cropping systems in Victoria, encompassing eight regions, five soil orders and four management classes (continuous cropping, crop–pasture rotation, sheep or beef pasture, and dairy pasture), and explored relationships between the C stocks and environment, soil and management. The results showed an extremely wide range in SOC, from 2 to 239 t C/ha (0–30 cm). Most of this variation was attributable to climate; almost 80% of the variation in SOC stock was related to annual rainfall or vapour pressure deficit (i.e. humidity). Texture-related soil properties accounted for a small, additional amount of variation in SOC. After accounting for climate, differences in SOC between management classes were small and often not significant. Management practices such as stubble retention, minimum cultivation, perennial pasture species, rotational grazing and fertiliser inputs were not significantly related to SOC stock. The relationships between SOC and environment, soil and management were scale-dependent. Within individual regions, the apparent influence of climate and soil properties on SOC stock varied, and in some regions, much of the variation in SOC stock remained unexplained. The results suggest that, across Victoria, there is a general hierarchy of influence on SOC stock: climate > soil properties > management class > management practices.

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Land use and management influences on surface soil organic carbon in Tasmania

Soil Research ◽

10.1071/sr12251 ◽

2013 ◽

Vol 51 (8) ◽

pp. 615 ◽

Cited By ~ 15

Author(s):

W. E. Cotching ◽

G. Oliver ◽

M. Downie ◽

R. Corkrey ◽

R. B. Doyle

Keyword(s):

Land Use ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Soil Carbon ◽

Bulk Density ◽

Management Practices ◽

Carbon Stocks ◽

Carbon Accounting ◽

Continuous Cropping ◽

Texture Contrast

The effects of environmental parameters, land-use history, and management practices on soil organic carbon (SOC) concentrations, nitrogen, and bulk density were determined in agricultural soils of four soil types in Tasmania. The sites sampled were Dermosols, Vertosols, Ferrosols, and a group of texture-contrast soils (Chromosol and Sodosol) each with a 10-year management history ranging from permanent perennial pasture to continuous cropping. Rainfall, Soil Order, and land use were all strong explanatory variables for differences in SOC, soil carbon stock, total nitrogen, and bulk density. Cropping sites had 29–35% less SOC in surface soils (0–0.1 m) than pasture sites as well as greater bulk densities. Clay-rich soils contained the greatest carbon stocks to 0.3 m depth under pasture, with Ferrosols containing a mean of 158 Mg C ha–1, Vertosols 112 Mg C ha–1, and Dermosols 107 Mg C ha–1. Texture-contrast soils with sandier textured topsoils under pasture had a mean of 69 Mg C ha–1. The range of values in soil carbon stocks indicates considerable uncertainty in baseline values for use in soil carbon accounting. Farmers can influence SOC more by their choice of land use than their day-to-day soil management. Although the influence of management is not as great as other inherent site variables, farmers can still select practices for their ability to retain more SOC.

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Effect of Integrated Nutrient Management on Performance of Chickpea (Cicer arietinum L.) and Soil Properties

International Journal of Environment and Climate Change ◽

10.9734/ijecc/2021/v11i530414 ◽

2021 ◽

pp. 156-162

Author(s):

Sumit Mukati ◽

Y. M. Kool ◽

Deepak Thakur ◽

Deepak Singune

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Soil Properties ◽

Management Practices ◽

Nutrient Management ◽

Management Practice ◽

Block Design ◽

Integrated Nutrient Management ◽

Available Nutrients ◽

Randomized Block Design

Present field experiment was conducted at farmer’s field in Ringondiya village, Madhya Pradesh during rabi season 2018-19 to study the effect of integrated nutrient management practices on performance of chickpea, basic soil properties and nutrient availability. The performance of chickpea (cv. JG-322) was evaluated under seven treatments viz., T1-Control, T2-100% N:P:K (20:50:20), T3-50% N:P:K + FYM @5 t ha-1, T4-50% N:P:K + vermicomposting @2 t ha-1, T5-50% N:P:K + PSB @4 kg ha-1, T6-50% N:P:K + FYM @5 t ha-1 + PSB @4 kg ha-1 and T7-50% N:P:K + vermicomposting @2 t ha-1 +PSB @4 kg ha-1 replicated thrice in a randomized block design. The grain yield, straw yield and harvest index of chickpea were determined at harvest. Similarly, the soil pH, electrical conductivity, soil organic carbon and soil available nutrients (N, P and K) were also determined in post harvest soil samples. The results revealed that the integrated nutrient management practice significantly improved the performance of chickpea. The soil organic carbon and available nutrients were also found increased under INM practices.

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Assessing Soil Organic Carbon in Soils to Enhance and Track Future Carbon Stocks

Agronomy ◽

10.3390/agronomy10081139 ◽

2020 ◽

Vol 10 (8) ◽

pp. 1139

Author(s):

Yun-Ya Yang ◽

Avi Goldsmith ◽

Ilana Herold ◽

Sebastian Lecha ◽

Gurpal S. Toor

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Management Practices ◽

Agricultural Soils ◽

Soil Layer ◽

Parent Material ◽

Sample Collection ◽

Surface Layers ◽

Grid Sampling ◽

Soc Stocks

Soils represent the largest terrestrial sink of carbon (C) on Earth, yet the quantification of the amount of soil organic carbon (SOC) is challenging due to the spatial variability inherent in agricultural soils. Our objective was to use a grid sampling approach to assess the magnitude of SOC variability and determine the current SOC stocks in three typical agricultural fields in Maryland, United States. A selected area in each field (4000 m2) was divided into eight grids (20 m × 25 m) for soil sample collection at three fixed depth intervals (0–20 cm, 20–40 cm, and 40–60 cm). Soil pH in all fields was significantly (p < 0.05) greater in the surface soil layer (6.2–6.4) than lower soil layers (4.7–5.9). The mean SOC stocks in the surface layers (0–20 cm: 1.7–2.5 kg/m2) were 47% to 53% of the total SOC stocks at 0–60 cm depth, and were significantly greater than sub-surface layers (20–40 cm: 0.9–1.3 kg/m2; 40–60 cm: 0.8–0.9 kg/m2). Carbon to nitrogen (C/N) ratio and stable C isotopic composition (δ13C) were used to understand the characteristics of SOC in three fields. The C/N ratio was positively corelated (r > 0.96) with SOC stocks, which were lower in sub-surface than surface layers. Differences in C/N ratios and δ13C signatures were observed among the three fields. The calculated values of SOC stocks at 0–60 cm depth ranged from 37 to 47 Mg/ha and were not significantly different in three fields likely due to the similar parent material, soil types, climate, and a short history of changes in management practices. A small variability (~10% coefficient of variation) in SOC stocks across eight sampling grids in each field suggests that re-sampling these grids in the future can lead to accurately determining and tracking changes in SOC stocks.

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