Soil microbial biomass and diversity respond to tillage and sulphur fertilizers

2001 ◽  
Vol 81 (5) ◽  
pp. 577-589 ◽  
Author(s):  
N. Z. Lupwayi ◽  
M. A. Monreal ◽  
G. W. Clayton ◽  
C. A. Grant ◽  
A. M. Johnston ◽  
...  

There is little information on the effects of S management strategies on soil microorganisms under zero tillage systems o n the North American Prairies. Experiments were conducted to examine the effects of tillage and source and placement of S on soil microbial biomass (substrate induced respiration) and functional diversity (substrate utilization patterns) in a canola-wheat rotation under conventional and zero tillage systems at three sites in Gray Luvisolic and Black Chernozemic soils. Conventional tillage significantly reduced microbial biomass and diversity on an acidic and C-poor Luvisolic soil, but it had mostly no significant effects on the near-neutral, C-rich Luvisolic and Chernozemic soils, which underlines the importance of soil C in maintaining a healthy soil. Sulphur had no significant effects on soil microbial biomass, and its effects on microbial diversity were more frequent on the near-neutral Luvisol, which was more S-deficient, than on the acidic Luvisol or the Chernozem. Significant S effects on microbial diversity were observed both in the bulk soil (negative effects, compared with the control) and rhizosphere (positive effects) of the acidic Luvisol, but all significant effects (positive) were observed in root rhizospheres in the other soils. Sulphur by tillage interactions on acidic Luvisolic soil indicated that the negative effects of S in bulk soil occurred mostly under zero tillage, presumably because the fertilizer is concentrated in a smaller volume of soil than under conventional tillage. Sulphate S effects, either negative or positive, on microbial diversity were usually greater than elemental S effects. Therefore, S application can have direct, deleterious effects on soil microorganisms or indirect, beneficial effects through crop growth, the latter presumably due to increased root exudation in the rhizosphere of healthy crops. Key Words: Biolog, conservation tillage, microbial biodiversity, rhizosphere, soil biological quality, S fertilizer type and placement

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


Soil Research ◽  
2011 ◽  
Vol 49 (4) ◽  
pp. 287 ◽  
Author(s):  
V. Gonzalez-Quiñones ◽  
E. A. Stockdale ◽  
N. C. Banning ◽  
F. C. Hoyle ◽  
Y. Sawada ◽  
...  

Since 1970, measurement of the soil microbial biomass (SMB) has been widely adopted as a relatively simple means of assessing the impact of environmental and anthropogenic change on soil microorganisms. The SMB is living and dynamic, and its activity is responsible for the regulation of organic matter transformations and associated energy and nutrient cycling in soil. At a gross level, an increase in SMB is considered beneficial, while a decline in SMB may be considered detrimental if this leads to a decline in biological function. However, absolute SMB values are more difficult to interpret. Target or reference values of SMB are needed for soil quality assessments and to allow ameliorative action to be taken at an appropriate time. However, critical values have not yet been successfully identified for SMB. This paper provides a conceptual framework which outlines how SMB values could be interpreted and measured, with examples provided within an Australian context.


2020 ◽  
Vol 19 (10) ◽  
pp. 2561-2570
Author(s):  
Zhen-cai SUN ◽  
Gui-tong LI ◽  
Cheng-lei ZHANG ◽  
Zhi-min WANG ◽  
Qi-mei LIN ◽  
...  

2011 ◽  
Vol 52 (No. 8) ◽  
pp. 345-352 ◽  
Author(s):  
G. Mühlbachová ◽  
P. Tlustoš

The effects of liming by CaO and CaCO<sub>3</sub> on soil microbial characteristics were studied during laboratory incubation of long-term contaminated arable and grassland soils from the vicinity of lead smelter near Př&iacute;bram (Czech Republic). The CaO treatment showed significant negative effects on soil microbial biomass C and its respiratory activity in both studied soils, despite the fact that microbial biomass C in the grassland soil increased sharply during the first day of incubation. The metabolic quotient (qCO<sub>2</sub>) in soils amended by CaO showed greater values than the control from the second day of incubation, indicating a possible stress of soil microbial pool. The vulnerability of organic matter to CaO could be indicated by the availability of K<sub>2</sub>SO<sub>4</sub>-extractable carbon that increased sharply, particularly at the beginning of the experiment. The amendment of soils by CaCO<sub>3 </sub>moderately increased the soil microbial biomass. The respiratory activity and qCO<sub>2</sub> increased sharply during the first day of incubation, however it is not possible to ascribe them only to microbial activities, but also to CaCO<sub>3</sub> decomposition in hydrogen carbonates, water and CO<sub>2</sub>. The pH values increased more sharply under CaO treatment in comparison to CaCO<sub>3</sub> treatment. The improvement of soil pH by CaCO<sub>3</sub> could be therefore more convenient for soil microbial communities.


2013 ◽  
Vol 16 (1) ◽  
pp. 63-68
Author(s):  
. Dermiyati ◽  
Eva Firdaus ◽  
Muhajir Utomo ◽  
Mas Achmad Syamsul Arif ◽  
Sutopo Ghani Nugroho

This research aimed to study the soil microbial biomass carbon (SMBC) under maize plant after a long-term application of nitrogen fertilizer and tillage systems (at the 37th growing season). The treatments were arranged in a factorial (3x3) in a randomized completely block design with 3 replications. The first factor was tillage systems, namely intensive tillage (IT) system, minimum tillage (MT) system, and no tillage (NT) system, and the second factor was the long-term application of nitrogen fertilizer, namely 0, 100, and 200 kg N ha-1. Data were analyzed using an orthogonal contrast test and a correlation test between SMBC and organic-C, total-N, and pH of the soil. The results showed that, in the rhizosphere and non-rhizosphere of maize plant, MT system increased the SMBC compared to NT and IT systems. However, application of long-term application of nitrogen fertilizer did not increase the SMBC. Nevertheless, fertilizer application of 100 kg N ha-1 increased the SMBC compare to 200 kg N ha-1.Furthermore, the combination of MT system and 100 kg N ha-1 could increase the SMBC compared to the other combined treatment between tillage systems and N fertilization doses. The SMBC was higher in the rhizosphere than in non-rhizosphere of maize plant.Keywords: Non-rhizosphere, rhizosphere, soil microbial biomass carbon, tillage systems


2012 ◽  
Vol 16 (5) ◽  
pp. 487-495 ◽  
Author(s):  
Elcio L. Balota ◽  
Oswaldo Machineski ◽  
Maria A. Matos

ABSTRACT The objective of this work was to evaluate the changes in microbial biomass C, N and P due to the application of pig slurry under different soil tillage systems. The experiment was established in a clayey Oxisol, Eutrophic Red Latossol in Palotina, PR. Different quantities of pig slurry (0, 30, 60 and 120 m3 ha-1 year-1) were applied to the soil prior to the summer and winter crop season under conventional tillage (CT) and no tillage (NT), in three replicates. The area was cultivated with soybean (Glycine max L.) or maize (Zea mays L.) in the summer and wheat (Triticum sativum Lam.) or oat (Avena sativa L.) in the winter. The soil samples were collected in March and October of 1998 and 1999 at depths of 0-5, 5-10 and 10-20 cm. The soil tillage and pig slurry application influenced the microbial biomass C, N and P. The microbial biomass and the microbial activity presented high sensibility to detect changes in the soil due to tillage and the application of pig slurry. The soil microbial biomass and Cmic/Corg relation increased as the quantity of applied pig slurry increased. The metabolic quotient under CT increased with depth while under NT it decreased. The soil microbial biomass was enriched in N and P under NT and as the quantity of applied pig slurry increased.


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