Labile soil organic matter in response to long-term cattle grazing on sloped rough fescue grassland in the foothills of the Rocky Mountains, Alberta

Extensive cattle grazing is the dominant land use in northern Australia. It has been suggested that grazing intensity and rainfall have profound effects on the dynamics of soil nutrients in northern Australia’s semi-arid rangelands. Previous studies have found positive, neutral and negative effects of grazing pressure on soil nutrients. These inconsistencies could be due to short-term experiments that do not capture the slow dynamics of some soil nutrients and the effects of interannual variability in rainfall. In a long-term cattle grazing trial in northern Australia on Brown Sodosol–Yellow Kandosol complex, we analysed soil organic matter and mineral nitrogen in surface soils (0–10 cm depth) 11, 12 and 16 years after trial establishment on experimental plots representing moderate stocking (stocked at the long-term carrying capacity for the region) and heavy stocking (stocked at twice the long-term carrying capacity). Higher soil organic matter was found under heavy stocking, although grazing treatment had little effect on mineral and total soil nitrogen. Interannual variability had a large effect on soil mineral nitrogen, but not on soil organic matter, suggesting that soil nitrogen levels observed in this soil complex may be affected by other indirect pathways, such as climate. The effect of interannual variability in rainfall and the effects of other soil types need to be explored further.

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Impacts of long-term plant residue management on soil organic matter quality, Pseudomonas community structure and disease suppressiveness

Soil Biology and Biochemistry ◽

10.1016/j.soilbio.2019.05.020 ◽

2019 ◽

Vol 135 ◽

pp. 396-406 ◽

Cited By ~ 7

Author(s):

Bryony E.A. Dignam ◽

Maureen O'Callaghan ◽

Leo M. Condron ◽

Jos M. Raaijmakers ◽

George A. Kowalchuk ◽

...

Keyword(s):

Organic Matter ◽

Community Structure ◽

Soil Organic Matter ◽

Residue Management ◽

Plant Residue ◽

Organic Matter Quality ◽

Soil Organic Matter Quality

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Functional soil organic matter fractions in response to long-term fertilizer management in a double-cropping paddy field of southern China

The Journal of Agricultural Science ◽

10.1017/s0021859621000125 ◽

2021 ◽

pp. 1-9

Author(s):

Haiming Tang ◽

Chao Li ◽

Lihong Shi ◽

Li Wen ◽

Kaikai Cheng ◽

...

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Paddy Field ◽

Southern China ◽

Rice Paddy ◽

Chemical Fertilizer ◽

Protection Mechanism ◽

Rice Paddy Field ◽

Double Cropping

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.

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Conversion of Brazilian savannah to agricultural land affects quantity and quality of labile soil organic matter

Geoderma ◽

10.1016/j.geoderma.2021.115509 ◽

2022 ◽

Vol 406 ◽

pp. 115509

Author(s):

Rafael S. Santos ◽

Martin Wiesmeier ◽

Dener M.S. Oliveira ◽

Jorge L. Locatelli ◽

Matheus S.C. Barreto ◽

...

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Agricultural Land ◽

Brazilian Savannah ◽

Labile Soil Organic Matter

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Impact of long-term cultivation on the status of organic matter and cadmium in soil

Canadian Journal of Soil Science ◽

10.4141/s00-071 ◽

2001 ◽

Vol 81 (3) ◽

pp. 349-355 ◽

Cited By ~ 9

Author(s):

D. F. E. McArthur ◽

P M Huang ◽

L M Kozak

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Significant Positive Correlation ◽

Soil Organic C ◽

Organic C ◽

Total Soil ◽

Total Organic C ◽

Soil Cd ◽

Cultivated Soils

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

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Priming and substrate quality interactions in soil organic matter models

Biogeosciences ◽

10.5194/bg-10-2089-2013 ◽

2013 ◽

Vol 10 (3) ◽

pp. 2089-2103 ◽

Cited By ~ 45

Author(s):

T. Wutzler ◽

M. Reichstein

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Balance Model ◽

Levels Of Abstraction ◽

Substrate Quality ◽

Substrate Limitation ◽

Energy Limitation ◽

Bare Fallow ◽

Different Levels

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.

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