Soil organic carbon (SOC) dynamics with and without residue incorporation in relation to different nitrogen fertilisation rates

Abstract Crop residue incorporation is recognised as a simple way to increase C input into the soil, with positive effects on C sequestration from the atmosphere. However, in some long-term experiments, a lack of response to soil C input levels has been observed as a consequence of saturation phenomena and/or interactions between C input and fertilisation. This paper analyses the outcomes of a long-term experiment in north-eastern Italy that started in 1966 and is still ongoing, where residue incorporation is compared with residue removal, over a range of mineral N fertilisations. A general decrease of SOC content was observed in the first 10 years of the experiment, followed by an approach to a steady state. However, SOC content differed markedly according to residue management and, in plots with residue incorporation, to N fertilisation. Considering 20 years as a compromise period for reaching a new equilibrium after a land-use change, the sequestration rate of residue incorporation in comparison with removal resulted as 0.17 t ha − 1 of C per year. The measured data were then simulated with Century, a model based on first-order decomposition kinetic, to evaluate if the data could be interpreted by this kind of decomposition process. Model performances were good in most cases, but overestimated SOC decomposition in the more limiting situations for C and N inputs. A possible explanation is given for this behaviour, involving a feed-back effect of the microbial community.

[1]  Keith Paustian,et al.  Modeling soil organic matter in organic-amended and nitrogen-fertilized long-term plots , 1992 .

[2]  E. Witter,et al.  Characteristics of the soil microbial biomass in soils from a long-term field experiment with different levels of C input , 1998 .

[3]  Keith Paustian,et al.  Management Controls on Soil Carbon , 2019, Soil Organic Matter in Temperate Agroecosystems.

[4]  W. Parton,et al.  A general model for soil organic matter dynamics: sensitivity to litter chemistry, texture and management. , 1994 .

[5]  Philip Smith,et al.  An overview of the permanence of soil organic carbon stocks: influence of direct human‐induced, indirect and natural effects , 2005 .

[6]  G. Buyanovsky,et al.  Post-harvest residue input to cropland , 1986, Plant and Soil.

[7]  Martin Körschens,et al.  Simulating trends in soil organic carbon in long-term experiments using the century model , 1997 .

[8]  Pete Smith,et al.  Carbon sequestration in the agricultural soils of Europe , 2004 .

[9]  Pete Smith.  Carbon sequestration in croplands: The potential in Europe and the global context , 2004 .

[10]  J. Hassink,et al.  The capacity of soils to preserve organic C and N by their association with clay and silt particles , 1997, Plant and Soil.

[11]  F. Skjøth,et al.  Tillage caused dispersion of phosphorus and soil in four 16-year old field experiments , 2000 .

[12]  Leif T. Jensen,et al.  A comparison of the performance of nine soil organic matter models using datasets from seven long-term experiments , 1997 .

[13]  W. Bowman,et al.  Variable effects of nitrogen additions on the stability and turnover of soil carbon , 2002, Nature.

[14]  T. Ando,et al.  Minimum available N requirement for microbial biomass P formation in a regosol , 1999 .

[15]  Jürgen K. Friedel,et al.  Review of mechanisms and quantification of priming effects. , 2000 .

[16]  Liwang Ma,et al.  Modeling Carbon and Nitrogen Dynamics for Soil Management , 2001 .

[17]  Luc Abbadie,et al.  Carbon input to soil may decrease soil carbon content , 2004 .

[18]  K. Paustian,et al.  Soil Organic Matter in Temperate Agroecosystems , 1997 .

[19]  A. Mariotti,et al.  The priming effect of organic matter: a question of microbial competition? , 2003 .

[20]  K. Paustian,et al.  Importance of macroaggregate dynamics in controlling soil carbon stabilization: short-term effects of physical disturbance induced by dry–wet cycles , 2001 .

[21]  K. Paustian,et al.  Stabilization mechanisms of soil organic matter: Implications for C-saturation of soils , 2002, Plant and Soil.

[22]  M. B. McGechan,et al.  A Review of Carbon and Nitrogen Processes in Four Soil Nitrogen Dynamics Models , 1998 .

[23]  F. Ellmer,et al.  Microbial activity in a sandy arable soil is governed by the fertilization regime , 2004 .

[24]  K. Svensson,et al.  Reversible transition between active and dormant microbial states in soil. , 2001, FEMS microbiology ecology.

[25]  D. Pennock,et al.  Cultivation-Induced Effects on Belowground Biomass and Organic Carbon , 2002 .

[26]  Rattan Lal,et al.  Agricultural soils as a sink to mitigate CO2 emissions , 1997 .

[27]  John Moncrieff,et al.  Incorporating microorganisms as decomposers into models to simulate soil organic matter decomposition , 2005 .

[28]  R. Lal.  Soil carbon sequestration to mitigate climate change , 2004 .

[29]  H. W. Hunt,et al.  Management options for reducing CO2 emissions from agricultural soils , 2000 .

[30]  A. Walkley,et al.  AN EXAMINATION OF THE DEGTJAREFF METHOD FOR DETERMINING SOIL ORGANIC MATTER, AND A PROPOSED MODIFICATION OF THE CHROMIC ACID TITRATION METHOD , 1934 .

[31]  A. Pedersen,et al.  Temporal variations in microbial biomass C and cellulolytic enzyme activity in arable soils: effects of organic matter input , 1999 .