Management induced changes of soil organic carbon on global croplands

Abstract. Soil organic carbon (SOC) is one of the largest terrestrial carbon stocks on Earth. The first meter of the Earths soils profile stores three times as much carbon as the vegetation and twice the amount of C in the atmosphere. SOC has been depleted by anthropogenic land cover change and agricultural management. However, the latter has so far not been well represented in global carbon stock assessments. While SOC models often simulate detailed biochemical processes that lead to the accumulation and decay of SOC, the management decisions driving these biophysical processes are still little investigated at the global scale. Here we develop a spatial explicit data set for agricultural management on cropland, considering crop production levels, residue returning rates, manure application, and the adoption of irrigation and tillage practices. We combine it with the IPCC Tier 2 steady-state soil model to create a half-degree resolution data set of SOC stocks and SOC stock changes for the first 30 cm of mineral soils. We estimate that due to arable farming, soils have lost around 26 GtC relative to a counterfactual natural state in 1975. Yet, within the period 1975–2010 this SOC debt has been decreasing again by a net quantity of 4 Gt SOC, which can be mainly traced back to an increased input of C in crop residues due to higher crop productivity. We also find that SOC is very sensitive to management decisions such as residue returning indicating the necessity to incorporate better management data in soil model simulations.

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Soil organic carbon and nitrogen pools as affected by compost applicationsto a sandy-loam soil in Québec

Canadian Journal of Soil Science ◽

10.4141/cjss07077 ◽

2008 ◽

Vol 88 (4) ◽

pp. 443-450 ◽

Cited By ~ 15

Author(s):

Joann K Whalen ◽

Hicham Benslim ◽

You Jiao ◽

Benjamin K Sey

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Crop Production ◽

Crop Residues ◽

Sandy Loam ◽

Mineral Fertilizer ◽

Cattle Manure ◽

Available Nitrogen ◽

Npk Fertilizers ◽

Total N

Compost contributes plant-available nutrients for crop production and adds partially decomposed carbon (C) to the soil organic carbon (SOC) pool. The effect of compost applications and other agricultural practices on SOC and total nitrogen (N) pools was determined in a sandy-loam Humic Gleysol at the Research Farm of McGill University, Ste-Anne-de-Bellevue, Quebec. Experimental plots with continuous silage corn (Zea mays L.) and silage corn-soybean (Glycine max L. Merr.) production were under conventional tillage (CT) or no-tillage (NT) management. Composted cattle manure was applied each spring at rates of 0, 5, 10 and 15 Mg (dry weight) ha-1 and supplemental NPK fertilizers were added to meet crop requirements. The C input from crop residues was affected by tillage, crop rotations and compost application, but differences in the SOC and total N pools were due to compost applications. After 5 yr, compost-amended plots gained 1.35 to 2.02 Mg C ha-1 yr-1 in the SOC pool and 0.18 to 0.24 Mg N ha-1 yr-1 in the total N pool, as compared with initial pool sizes when the experiment was initiated. These gains in SOC and total N were achieved with agronomic rates of compost and supplemental NPK fertilizers, selected to match the phosphorus requirements of silage corn. Such judicious use of compost has the potential to increase the SOC and total N pools in agroecosystems under annual crop production. Key words: Composted cattle manure, corn silage, mineral fertilizer, plant-available nitrogen, soil organic carbon

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Impact of crop residue management on crop production and soil chemistry after seven years of crop rotation in temperate climate, loamy soils

PeerJ ◽

10.7717/peerj.4836 ◽

2018 ◽

Vol 6 ◽

pp. e4836 ◽

Cited By ~ 20

Author(s):

Marie-Pierre Hiel ◽

Sophie Barbieux ◽

Jérôme Pierreux ◽

Claire Olivier ◽

Guillaume Lobet ◽

...

Keyword(s):

Organic Carbon ◽

Crop Production ◽

Crop Residue ◽

Crop Residues ◽

Conventional Tillage ◽

Residue Management ◽

Temperate Climate ◽

Reduced Tillage ◽

Crop Residue Management ◽

The Impact

Society is increasingly demanding a more sustainable management of agro-ecosystems in a context of climate change and an ever growing global population. The fate of crop residues is one of the important management aspects under debate, since it represents an unneglectable quantity of organic matter which can be kept in or removed from the agro-ecosystem. The topic of residue management is not new, but the need for global conclusion on the impact of crop residue management on the agro-ecosystem linked to local pedo-climatic conditions has become apparent with an increasing amount of studies showing a diversity of conclusions. This study specifically focusses on temperate climate and loamy soil using a seven-year data set. Between 2008 and 2016, we compared four contrasting residue management strategies differing in the amount of crop residues returned to the soil (incorporation vs. exportation of residues) and in the type of tillage (reduced tillage (10 cm depth) vs. conventional tillage (ploughing at 25 cm depth)) in a field experiment. We assessed the impact of the crop residue management on crop production (three crops—winter wheat, faba bean and maize—cultivated over six cropping seasons), soil organic carbon content, nitrate (${\mathrm{NO}}_{3}^{-}$), phosphorus (P) and potassium (K) soil content and uptake by the crops. The main differences came primarily from the tillage practice and less from the restitution or removal of residues. All years and crops combined, conventional tillage resulted in a yield advantage of 3.4% as compared to reduced tillage, which can be partly explained by a lower germination rate observed under reduced tillage, especially during drier years. On average, only small differences were observed for total organic carbon (TOC) content of the soil, but reduced tillage resulted in a very clear stratification of TOC and also of P and K content as compared to conventional tillage. We observed no effect of residue management on the ${\mathrm{NO}}_{3}^{-}$ content, since the effect of fertilization dominated the effect of residue management. To confirm the results and enhance early tendencies, we believe that the experiment should be followed up in the future to observe whether more consistent changes in the whole agro-ecosystem functioning are present on the long term when managing residues with contrasted strategies.

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Soil Organic Carbon Dynamics in Black Soils of China Under Different Agricultural Management Systems

Communications in Soil Science and Plant Analysis ◽

10.1081/css-120019103 ◽

2003 ◽

Vol 34 (7-8) ◽

pp. 973-984 ◽

Cited By ~ 73

Author(s):

Xiaobing Liu ◽

Xiaozeng Han ◽

Chunyu Song ◽

S. J. Herbert ◽

Baoshan Xing

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Carbon Dynamics ◽

Agricultural Management ◽

Management Systems ◽

Soil Organic Carbon Dynamics

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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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