scholarly journals Integrative Molecular Biogeochemistry of Soil Organic Matter with Long-Term Litter Manipulation in Temperate Forests

2020 ◽  
Author(s):  
Myrna J. Simpson ◽  
Kate Lajtha ◽  
Richard Bowden
2019 ◽  
Vol 135 ◽  
pp. 396-406 ◽  
Author(s):  
Bryony E.A. Dignam ◽  
Maureen O'Callaghan ◽  
Leo M. Condron ◽  
Jos M. Raaijmakers ◽  
George A. Kowalchuk ◽  
...  

Author(s):  
Haiming Tang ◽  
Chao Li ◽  
Lihong Shi ◽  
Li Wen ◽  
Kaikai Cheng ◽  
...  

Abstract Soil organic matter (SOM) and its fractions play an important role in maintaining or improving soil quality and soil fertility. Therefore, the effects of a 34-year long-term fertilizer regime on six functional SOM fractions under a double-cropping rice paddy field of southern China were studied in the current paper. The field experiment included four different fertilizer treatments: chemical fertilizer alone (MF), rice straw residue and chemical fertilizer (RF), 30% organic manure and 70% chemical fertilizer (OM) and without fertilizer input as control (CK). The results showed that coarse unprotected particulate organic matter (cPOM), biochemically, physically–biochemically and chemically protected silt-sized fractions (NH-dSilt, NH-μSilt and H-dSilt) were the main carbon (C) storage fractions under long-term fertilization conditions, accounting for 16.7–26.5, 31.1–35.6, 16.2–17.3 and 7.5–8.2% of the total soil organic carbon (SOC) content in paddy soil, respectively. Compared with control, OM treatment increased the SOC content in the cPOM, fine unprotected POM fraction, pure physically protected fraction and physico-chemically protected fractions by 58.9, 106.7, 117.6 and 28.3%, respectively. The largest proportion of SOC to total SOC in the different fractions was biochemically protected, followed by chemically and unprotected, and physically protected were the smallest. These results suggested that a physical protection mechanism plays an important role in stabilizing C of paddy soil. In summary, the results showed that higher functional SOM fractions and physical protection mechanism play an important role in SOM cycling in terms of C sequestration under the double-cropping rice paddy field.


2016 ◽  
Vol 9 (2) ◽  
pp. 841-855 ◽  
Author(s):  
Bertrand Guenet ◽  
Fernando Esteban Moyano ◽  
Philippe Peylin ◽  
Philippe Ciais ◽  
Ivan A Janssens

Abstract. Priming of soil carbon decomposition encompasses different processes through which the decomposition of native (already present) soil organic matter is amplified through the addition of new organic matter, with new inputs typically being more labile than the native soil organic matter. Evidence for priming comes from laboratory and field experiments, but to date there is no estimate of its impact at global scale and under the current anthropogenic perturbation of the carbon cycle. Current soil carbon decomposition models do not include priming mechanisms, thereby introducing uncertainty when extrapolating short-term local observations to ecosystem and regional to global scale. In this study we present a simple conceptual model of decomposition priming, called PRIM, able to reproduce laboratory (incubation) and field (litter manipulation) priming experiments. Parameters for this model were first optimized against data from 20 soil incubation experiments using a Bayesian framework. The optimized parameter values were evaluated against another set of soil incubation data independent from the ones used for calibration and the PRIM model reproduced the soil incubations data better than the original, CENTURY-type soil decomposition model, whose decomposition equations are based only on first-order kinetics. We then compared the PRIM model and the standard first-order decay model incorporated into the global land biosphere model ORCHIDEE (Organising Carbon and Hydrology In Dynamic Ecosystems). A test of both models was performed at ecosystem scale using litter manipulation experiments from five sites. Although both versions were equally able to reproduce observed decay rates of litter, only ORCHIDEE–PRIM could simulate the observed priming (R2  =  0.54) in cases where litter was added or removed. This result suggests that a conceptually simple and numerically tractable representation of priming adapted to global models is able to capture the sign and magnitude of the priming of litter and soil organic matter.


2001 ◽  
Vol 81 (3) ◽  
pp. 349-355 ◽  
Author(s):  
D. F. E. McArthur ◽  
P M Huang ◽  
L M Kozak

Research has suggested a link between the bioavailability of soil Cd and total soil organic matter. However, some research suggested a negative relationship between total soil organic matter and bioavailable soil Cd while other research suggested a positive relationship. This study investigated the relationship between soil Cd and both the quantity and quality of soil organic matter as influenced by long-term cultivation. Two Orthic Chernozemic surface soil samples, one from a virgin prairie and the other from an adjacent cultivated prairie, were collected from each of 12 different sites throughout southern Saskatchewan, Canada. The samples were analyzed for total organic C, total Cd, Cd availability index (CAI), and pH. The nature of the soil organic matter was investigated with 13C Cross Polarization Magic Angle Spinning Nuclear Magnetic Resonance spectroscopy (13C CPMAS NMR). The total soil Cd, CAI, and total soil organic C of the cultivated soils were significantly lower than those of the virgin soils whereas the opposite trend was observed for the soil pH and the aromaticity of the organic C. The reduced CAI in the cultivated soils was related to the increase in both the soil pH and the aromaticity of the organic C. No relationship was found between the CAI and the soil organic C content, but a significant positive correlation was found between total organic C and total Cd in both the virgin and the cultivated soils. As well, a significant positive correlation was found between the fraction of total Cd removed from the soil after long-term cultivation and the corresponding fraction of organic C removed. Key words: Long-term cultivation, soil organic matter, 13C CPMAS NMR, cadmium


2019 ◽  
Vol 124 (1) ◽  
pp. 2-17 ◽  
Author(s):  
Erin M. Stacy ◽  
Asmeret Asefaw Berhe ◽  
Carolyn T. Hunsaker ◽  
Dale W. Johnson ◽  
S. Mercer Meding ◽  
...  

2013 ◽  
Vol 10 (3) ◽  
pp. 2089-2103 ◽  
Author(s):  
T. Wutzler ◽  
M. Reichstein

Abstract. Interactions between different qualities of soil organic matter (SOM) affecting their turnover are rarely represented in models. In this study, we propose three mathematical strategies at different levels of abstraction to represent those interactions. By implementing these strategies into the Introductory Carbon Balance Model (ICBM) and applying them to several scenarios of litter input, we show that the different levels of abstraction are applicable at different timescales. We present a simple one-parameter equation of substrate limitation that can straightforwardly be implemented into other models of SOM dynamics at decadal timescale. The study demonstrates how substrate quality interactions can explain patterns of priming effects, accelerate turnover in FACE experiments, and the slowdown of decomposition in long-term bare fallow experiments as an effect of energy limitation of microbial biomass. The mechanisms of those interactions need to be further scrutinized empirically for a more complete understanding. Overall, substrate quality interactions contribute to both understanding and quantitatively modelling SOM dynamics.


2020 ◽  
Vol 21 (2) ◽  
pp. 160-168
Author(s):  
N. A. Kodochilova ◽  
T. S. Buzynina ◽  
L. D. Varlamova ◽  
E. A. Katerova

The studies on assessment of changes in the content and composition of soil organic matter under the influence of the systematic use of mineral fertilizers (NPK)1, (NPK)2, (NPK)3 against the background of the aftereffect of single liming in doses of 1.0 and 2.0 h. a. (control – variants without fertilizers and lime) were conducted in the conditions of the Nizhny Novgorod region in a long – term stationary experiment on light-grey forest soil. The research was carried out upon comple-tion of the fifth rotation of the eight-field crop rotation. The results of the study showed that for 40 years (from 1978 to 2018) the humus content in the soil (0-20 cm) decreased by 0.19-0.52 abs. % in variants as compared to the original (1.60 %); though, humus mineralization was less evident against the background of long-term use of mineral fertilizers compared to non-fertilized control. The higher humus content in the topsoil was noted in the variants with minimal (NPK)1 and increased (NPK)2 doses of fertilizer – 1.41 and 1.25 %, respectively. The humus content in non-fertilized soil and when applying high (NPK)3 doses of mineral fertilizers was almost identical – 1.08-1.09 %. The predominant group in the composition of humus were humic acids, the content of which in the experiment on average was 37.8 % of the total carbon with an evident decrease from 42.6 % in the control to 31.8% when applying increased doses of mineral fertilizers. The aftereffect of liming, carried out in 1978, was unstable and did not significantly affect the content and composition of soil organic matter.


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