Estimating the active and total soil microbial biomass by kinetic respiration analysis

2000 ◽  
Vol 32 (1) ◽  
pp. 73-81 ◽  
Author(s):  
S. A. Blagodatsky ◽  
O. Heinemeyer ◽  
J. Richter
1989 ◽  
Vol 69 (4) ◽  
pp. 849-855 ◽  
Author(s):  
S. C. SRIVASTAVA ◽  
A. K. JHA ◽  
J. S. SINGH

Soil biomass C, N and P were determined for a native forest site, an unmined deforested site and an age-series of adjacent coal mine spoils (5, 10, 12, 16 and 20 yr). Biomass C ranged from 209 to 867 μg g−1 soil, biomass N from 20 to 75 μg g−1 soil and biomass P from 7 to 29 μg g−1 soil. Biomass C, N and P were linearly related to each other. Biomass C was also related to the root biomass. Biomass N with a mean C:N ratio of 11.8 accounted for 2.2–4.2% of the total soil N and was positively related to the mineral N of soil. Biomass C:P ratio ranged from 27.6 to 31.0%. The biomass P was significantly related to the bicarbonate soluble soil Pi. Soil microbial biomass was characterized by a mean C:N:P ratio of 29:3:1. Soil microbial C, N and P were positively related with the age of mine spoils, the values for the youngest spoil (5 yr old) being about four times lower compared to native forest soil. Total soil N was also positively related with age of spoil. The data suggest that microbial biomass can be taken as a functional index of soil redevelopment. Key words: Surface coal mining, soil microbial biomass C, biomass N, biomass P, mine spoil


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wen Yang ◽  
Nasreen Jeelani ◽  
Andong Cai ◽  
Xiaoli Cheng ◽  
Shuqing An

AbstractCoastal reclamation seriously disturbs coastal wetland ecosystems, while its influences on soil microbial communities remain unclear. In this study, we examined the impacts of coastal reclamation on soil microbial communities based on phospholipid fatty acids (PLFA) analysis following the conversion of Phragmites australis wetlands to different land use types. Coastal reclamation enhanced total soil microbial biomass and various species (i.e., gram-positive bacterial, actinomycete, saturated straight-chain, and branched PLFA) following the conversion of P. australis wetland to aquaculture pond, wheat, and oilseed rape fields. In contrast, it greatly decreased total soil microbial biomass and various species following the conversion of P. australis wetland to town construction land. Coastal reclamation reduced fungal:bacterial PLFA, monounsaturated:branched PLFA ratios, whereas increasing gram-positive:gram-negative PLFA ratio following the conversion of P. australis wetland to other land use types. Our study suggested that coastal reclamation shifted soil microbial communities by altering microbial biomass and community composition. These changes were driven primarily by variations in soil nutrient substrates and physiochemical properties. Changes in soil microbial communities following coastal reclamation impacted the decomposition and accumulation of soil carbon and nitrogen, with potential modification of carbon and nitrogen sinks in the ecosystems, with potential feedbacks in response to climate change.


1999 ◽  
Vol 79 (2) ◽  
pp. 273-280 ◽  
Author(s):  
N. Z. Lupwayi ◽  
W. A. Rice ◽  
G. W. Clayton

Soil organic matter is important both from an agronomic and an environmental perspective because it affects the capacity of the soil to sustain crop growth, and it is a source and sink of atmospheric CO2-C. Soil microbial biomass comprises a small proportion of total soil organic matter, but it is more dynamic than total soil organic matter. Therefore, measurements of soil microbial biomass may show the effects of soil management on potential changes in soil organic matter before such effects can be detected by measuring total soil organic matter. The effects of tillage and crop rotation on soil microbial biomass and activity were studied in 1995–1997 in the wheat phase of different cropping rotations that had been established in 1992 under zero tillage or conventional tillage in northern Alberta. Soil microbial biomass was often significantly (P < 0.05) higher, but never significantly lower, under zero tillage than under conventional tillage. However, CO2 evolution (basal respiration) was usually higher under conventional tillage than under zero tillage, resulting in higher specific respiration (qCO2) under conventional tillage than under zero tillage. The higher additions but lower losses of labile C under zero tillage mean that more C is sequestered in the soil in the zero-tillage system. Thus, this system contributes less to atmospheric CO2 than conventional tillage, and that soil organic matter accumulates more under zero tillage. Plots preceded by summerfallow, especially under conventional tillage, usually had the lowest microbial biomass and CO2 evolution, and plots preceded by legume crops had higher microbial biomass and lower qCO2 than other treatments. Tillage and rotation had little effect on total soil organic matter 5 yr after the treatments had been imposed, probably because of the cold climate of northern Alberta, but the results confirm that the labile forms of soil C are more sensitive indicators of soil organic C trends than total soil organic C. These effects of tillage and rotation on soil microbial biomass were similar to those on microbial diversity reported previously. These results confirm that zero tillage and legume-based crop rotations are more sustainable crop management systems than conventional tillage and fallowing in the Gray Luvisolic soils of northern Alberta. Key words: Carbon sequestration, carbon mineralization, microbial activity, soil organic matter


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