Effect of temperature on soil microbial biomass and its metabolic quotient in situ under different tillage systems

1995 ◽  
Vol 19 (2-3) ◽  
pp. 227-230 ◽  
Author(s):  
Roberto Alvarez ◽  
Oscar J. Santanatoglia ◽  
Roberto Garc�a
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


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


2020 ◽  
Author(s):  
Ilka Schmoock ◽  
Deborah Linsler ◽  
Mignon Sandor ◽  
Rainer Georg Joergensen ◽  
Martin Potthoff

<p>Over the last decades, reduced tillage became more and more important as a suitable soil management practice. Moreover, reduced tillage is expected to promote a healthy and active soil life as a feature of sustainable agricultural. The determination of soil microbial biomass and microbial indices are suitable indicators for estimating soil quality. This study follows a regional approach and focusses at four different countries with varying environmental conditions at long-term experimental field-sites (LTE´s) across Europe. Soil microbial biomass carbon (SMB-C), the metabolic quotient (<em>q</em>CO<sub>2</sub>) and the ratio of SMB-C to soil organic carbon (SOC) were measured as microbial properties.</p><p>Our contribution to the ongoing discussion of the effectiveness of non-conventional tillage systems is (i) the comparison between conventional ploughing (CT) and minimum tillage (MT), (ii) the comparison of inversion vs. not inversion tillage at the same working depth, (iii) the comparison of ploughing vs. no-tillage (NT), (iv) the comparison between reduced tillage systems with each other (MT vs. NT).</p><p>We found a significant difference of SMB-C for CT and MT between 0 and 10 cm in Germany and Sweden, but no difference between tillage treatments for the sampled soil profile (0-30 cm). We highlight that tillage changed the vertical distribution of SMB-C, showing similar values among soil depths under CT and a depth gradient with decreasing values for MT.</p><p>The comparison of inversion vs. not inversion tillage at the same working depth in Romania showed no differences between CT and MT at all. This suggests that humus-rich soils seem to be more resistant to tillage-related disturbances. The working depth might have a greater impact for both, inversion and non-inversion tillage than the type of the tillage system itself.</p><p>For the comparison of CT and NT, we used the field-sites in Spain and Sweden. In Spain, NT was clearly of advantage for microbial biomass and activity, compared to CT. This was true for the whole sampled soil profile (0-30 cm) whereas in Sweden differences could only be detected between SMB-C levels in two soil depths. Our results indicate that the effect of tillage seems to be smaller in cold-temperate areas.</p><p>Comparing MT and NT in Sweden, we found no difference in SMB-C between these two forms of conservation tillage, neither in the first centimeters, nor in the whole sampled profile. Consequently, minimum tillage seems to be an alternative in cold and moist regions if no-tillage is not possible to apply without reducing soil quality or crop yields.</p><p>We conclude that even if minimum and no-tillage are generally beneficial for microorganisms, there is a big variance between the different forms of reduced tillage systems. Thus, statements cannot be made across different soils and machine types, but have to be made on a regional scale.</p><p> </p>


2011 ◽  
Vol 35 (6) ◽  
pp. 1873-1883 ◽  
Author(s):  
Elcio Liborio Balota ◽  
Pedro Antonio Martins Auler

To mitigate soil erosion and enhance soil fertility in orange plantations, the permanent protection of the inter-rows by cover species has been suggested. The objective of this study was to evaluate alterations in the microbial biomass, due to different soil tillage systems and intercropped cover species between rows of orange trees. The soil of the experimental area previously used as pasture (Brachiaria humidicola) was an Ultisol (Typic Paleudult) originating from Caiuá sandstone in the northwestern part of the State of Paraná, Brazil. Two soil tillage systems were evaluated: conventional tillage (CT) in the entire area and strip tillage (ST) (strip width 2 m), in combination with different ground cover management systems. The citrus cultivar 'Pera' orange (Citrus sinensis) grafted onto 'Rangpur' lime rootstock was used. Soil samples were collected after five years of treatment from a depth of 0-15 cm, under the tree canopy and in the inter-row, in the following treatments: (1) CT and an annual cover crop with the leguminous species Calopogonium mucunoides; (2) CT and a perennial cover crop with the leguminous peanut Arachis pintoi; (3) CT and an evergreen cover crop with Bahiagrass Paspalum notatum; (4) CT and a cover crop with spontaneous Brachiaria humidicola grass vegetation; and (5) ST and maintenance of the remaining grass (pasture) of Brachiaria humidicola. Soil tillage and the different cover species influenced the microbial biomass, both under the tree canopy and in the inter-row. The cultivation of brachiaria increased C and N in the microbial biomass, while bahiagrass increased P in the microbial biomass. The soil microbial biomass was enriched in N and P by the presence of ground cover species and according to the soil P content. The grass species increased C, N and P in the soil microbial biomass from the inter-row more than leguminous species.


Soil Research ◽  
2001 ◽  
Vol 39 (3) ◽  
pp. 491 ◽  
Author(s):  
S. Saggar ◽  
C. B. Hedley ◽  
G. J. Salt

To understand the effects of agroforestry on soil biological processes we assessed the conditions in Pinus radiata plantations of 50, 100, 200, and 400 stems/ha after 25 years of growth, and in a grassland. Agroforestry resulted in a 15–25% decline in soil organic C and N compared with grassland, and had a significant negative influence on soil microbial biomass. There was less microbial C and N in soils under 50–400 stems/ha of P. radiata than in soils under grassland (0 stems/ha). Soil carbon decomposition and microbial activity were measured by trapping the carbon dioxide produced by incubating soils over a 60-week period. The results showed that soil C decomposition rates were ~1.5 times as much (c. 15 mg CO2-C/kg soil) in soil from grassland as in that from plots with 50 or100 stems/ha (c. 10 mg CO2-C/kg soil), and were further reduced to one half (c. 5.5 mg CO2-C/kg soil) in the plots with 200 or 400 stems/ha. The soils under P. radiata gave off less carbon dioxide per unit of biomass (the metabolic quotient) than soils under grassland. These shifts in microbial biomass and its metabolic quotients appear to be associated with differences in the quantity and ‘quality’ of inputs and soil organic matter decomposition rates, and to reflect the land use change from grassland to forest. Given the general ability of soil microbial biomass to recolonise depopulated areas after tree harvest, we see no problem in restoring populations of these soil organisms vital in controlling nutrient cycling after tree felling, provided adequate adjustments to soil pH are made.


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