Enzymatic and microbial activities as influenced by tillage and fertilization in a semi-arid Mediterranean agroecosystem

2021 ◽  
Author(s):  
Francesco De Mastro ◽  
Andreina Traversa ◽  
Gennaro Brunetti ◽  
Evgenia Blagodatskaya
Keyword(s):  
Microbial Biomass ◽  
Turnover Rate ◽  
Microbial Growth ◽  
Soil Depth ◽  
Conventional Tillage ◽  
Microbial Activities ◽  
Total Microbial Biomass ◽  
Tillage Practice ◽  
Potential Activity ◽  
Soil Organics

<p>Soil enzymes respond rapidly to changes in soil managements, and therefore are used as early and sensitive indicators of alteration in soil properties induced by tillage and additions of fertilizers. The aim of this work was to compare the effects of different tillage (no, minimum, and conventional tillage), fertilization and soil depth (0-30, 30-60 and 60- 90 cm) on the microbial biomass, enzyme activity and their relationship with soil nutrients in a semiarid Mediterranean agro-ecosystem. Growing and total microbial biomass decreased with depth together with the activities of β-glucosidase and N-acetyl-β-glucosaminidase presumably because of the reduced carbon and oxygen content in the deeper layers of soils. The fertilization stimulated fast-growing microorganisms with low affinity of enzyme systems to substrate, enhanced the growing microbial biomass and facilitated the turnover rate of soil organics. Under no tillage, all enzymes showed higher potential activity in top layers of fertilized plots as compared with non-fertilized ones. The minimum tillage practice increased the growing microbial biomass, and stimulated N- and P-acquiring enzymes due to  increased nutrients limitation. Parameters of microbial growth and enzyme kinetics are suitable indicators of microbial activity in semiarid Mediterranean agroecosystems.</p>

scholarly journals Comparative Study on Soil Microbial Biomass in Tarai and Hill Sal (Shorearobusta Gaertn.) Forests of Tropical Region in Eastern Nepal

2020 ◽  
Vol 19 (1) ◽  
pp. 16-25
Author(s):  
Krishna Prasad Bhattarai ◽  
Tej Narayan Mandal
Keyword(s):  
Microbial Biomass ◽  
Comparative Study ◽  
Rainy Season ◽  
Turnover Rate ◽  
Soil Microbial Biomass ◽  
Soil Depth ◽  
Soil Samples ◽  
Tropical Region ◽  
Soil Microbial ◽  
Sal Forest

A comparative study was conducted to investigate the effect of altitudinal variation and seasonality on soil microbial biomass carbon (MB-C), nitrogen (MB-N), and phosphorus (MB-P) between Tarai Sal forest (TSF) and Hill Sal forest (HSF) of the tropical region in eastern Nepal. Soil microbial biomass was estimated by chloroform fumigation - extraction method in summer, rainy and winter seasons in the upper (0-15 cm) soil depth in both forests. Pre-conditioned soil samples were saturated with purified liquid chloroform, represented fumigated sample. Another set of soil samples without using chloroform, represented unfumigated samples and soil biomass was estimated from these samples. MB-C, MB-N, and MB-P were higher by 66%, 31%, and 9%, respectively, in HSF than TSF. Distinct seasonality was observed in soil microbial biomass. It was maximum in summer and minimum in rainy season in both the forest stands. The value decreased from summer to rainy season by 46 to 67% in HSF and by 32 to 80% in TSF. Higher soil microbial biomass in the summer season may be due to its accumulation in soil when the plant growth and nutrient demand are minimal. Analysis of variance suggested that MB-C, MB-N, and MB-P were significantly different for both sites and seasons (P < 0.001). Soil organic carbon, TN, and TP were positively correlated with MB-C, MB-N, and MB-P in both the forests. In conclusion, the higher value of soil microbial biomass in HSF may be due to the higher concentration of soil organic matter and decreasing turnover rate of microbial biomass due to higher altitude. On the other hand, the lower value of microbial biomass at TSF may indicate its fast turnover rate due to lowland tropics to enhance the nutrient cycling process.

Influence of 10 years of conservation tillage on some biological properties of a fine sandy loam in the potato phase of two crop rotations in Atlantic Canada

2009 ◽  
Vol 89 (4) ◽  
pp. 391-402 ◽  
Author(s):  
M R Carter ◽  
R D Peters ◽  
C Noronha ◽  
J Kimpinski
Keyword(s):  
Sandy Loam ◽  
Conservation Tillage ◽  
Soil Depth ◽  
Conventional Tillage ◽  
Biological Properties ◽  
Soil Organic C ◽  
Tillage Practice ◽  
Organic C ◽  
Fine Sandy Loam ◽  
Potato Rotation

Conservation practices in potato (Solanum tuberosum L.) cropping systems can reduce excess tillage, provide crop residue cover, and maintain crop productivity; however, little is known about their long-term influence on soil biota and biological properties. Conservation tillage was evaluated in two potato rotations: a 2-yr barley-potato rotation and 3-yr clover-based (barley-red clover-potato) rotation initiated in 1994 on a fine sandy loam (Orthic Podzol) in Prince Edward Island, eastern Canada. Soil samples were obtained in 2003 from the 0- to 10-cm soil depth of the potato phase of both rotations to evaluate the influence of conservation, compared with conventional tillage, on changes in soil fertility, soil structural properties, soil C and N fractions, soil-borne pathogens, nematode communities, and micro-arthropod (Collembola and Acari) communities. The 3-yr conservation tillage practice improved soil structural stability, increased soil extractable P and K, increased soil organic C and total N and their particulate fractions, compared with the other treatments. Comparisons with earlier studies indicated that soil organic C had reached an equilibrium level at the 0- to 10-cm soil depth. Reduction of potato disease caused by Rhizoctonia solani was evident in the 3-yr rotation, compared with the 2-yr rotation, but was not influenced by tillage practice. Plant parasitic nematodes were not greatly influenced by rotation and tillage treatments; however, densities of the beneficial bacterial-feeding nematodes were increased under the 3-yr conservation tillage treatment. The abundance of micro-arthropods was increased by conservation tillage, while their diversity was mainly influenced by the rotation cycle rather than tillage practice. Overall, the 3-yr conservation tillage treatment provided a more beneficial soil biological condition than the other treatments, especially when compared with the 2-yr conventional tillage practice. Key words: Conservation systems, potato rotation, fine sandy loam, soil fertility, soil organic C and N fractions, soil structure, soil-borne pathogens, nematode, Collembola; Acari

scholarly journals Soil depth gradients in microbial growth kinetics under deeply- vs. shallow-rooted plants

2021 ◽  
Author(s):  
Kyungjin Min ◽  
Eric Slessarev ◽  
Megan Patricia Kan ◽  
Karis Mcfarlane ◽  
Erik Oerter ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Growth Kinetics ◽  
Microbial Growth ◽  
Growth Parameters ◽  
Soil Depth ◽  
Rooting Depth ◽  
Deep Soil ◽  
Switch Grass ◽  
Microbial Growth Kinetics ◽  
Deep Soils

Climate-smart land management practices that replace shallow-rooted annual crop systems with deeply-rooted perennial plants can contribute to soil carbon sequestration. However, deep soil carbon accrual may be influenced by active microbial biomass and their capacity to assimilate fresh carbon at depth. Incorporating active microbial biomass, dormancy and growth in models can improve our ability to predict the capacity of soil to store carbon. But, so far, the microbial parameters that are needed for such modeling are poorly constrained, especially in deep soil layers. Here, we investigated whether a change in crop rooting depth affects microbial growth kinetics in deep soils compared to surface soils. We used a lab incubation experiment and growth kinetics model to estimate how microbial parameters vary along 240 cm of soil depth in profiles under shallow- (soy) and deeply-rooted plants (switch grass) 11 years after plant cover conversion. We also assessed resource origin and availability (total organic carbon, 14C, dissolved organic carbon, specific UV absorbance, total nitrogen, total dissolved nitrogen) along the soil profiles to examine associations between soil chemical and biological parameters. Even though root biomass was higher and rooting depth was deeper under switch grass than soy, resource availability and microbial growth parameters were generally similar between vegetation types. Instead, depth significantly influenced soil chemical and biological parameters. For example, resource availability, and total and relative active microbial biomass decreased with soil depth. Decreases in the relative active microbial biomass coincided with increased lag time (response time to external carbon inputs) along the soil profiles. Even at a depth of 210-240 cm, microbial communities were activated to grow by added resources within a day. Maximum specific growth rate decreased to a depth of 90 cm and then remained consistent in deeper layers. Our findings show that > 10 years of vegetation and rooting depth changes may not be long enough to alter microbial growth parameters, and suggest that at least a portion of the microbial community in deep soils can grow rapidly in response to added resources. Our study determined microbial growth parameters that can be used in models to simulate carbon dynamics in deep soil layers.

Divergent vertical distributions of microbial biomass with soil depth among groups and land uses

2021 ◽  
Vol 292 ◽  
pp. 112755
Author(s):  
Tingting Sun ◽  
Yugang Wang ◽  
Manuel Esteban Lucas-Borja ◽  
Xin Jing ◽  
Wenting Feng
Keyword(s):  
Microbial Biomass ◽  
Soil Depth ◽  
Land Uses ◽  
Vertical Distributions

Effect of forest harvesting and slash piling on microbial biomass and respiration in Newfoundland boreal forests

2007 ◽  
Vol 87 (4) ◽  
pp. 455-458 ◽  
Author(s):  
Martin T Moroni ◽  
Paul Q Carter ◽  
Dean W Strickland ◽  
Franz Makeschin ◽  
Don-Roger Parkinson ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Key Words ◽  
Boreal Forests ◽  
Fungal Biomass ◽  
Forest Harvesting ◽  
Organic Layer ◽  
Total Microbial Biomass ◽  
Organic Layers ◽  
Respiration Rates ◽  
Fumigation Extraction

Clearcutting Newfoundland boreal forests significantly reduced organic layer fungal and total microbial biomass in clearcut areas with and without slash cover, compared with forested plots. However, aerobically incubated respiration rates were highest in organic layers from clearcut areas under slash, intermediate under forests, and lowest from clearcut areas without slash. Key words: Carbon, ergosterol, fumigation–extraction, fungal biomass, harvest slash, nitrogen

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 ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Microbial Diversity ◽  
Soil Microorganisms ◽  
Soil Microbial Biomass ◽  
Conventional Tillage ◽  
Bulk Soil ◽  
Zero Tillage ◽  
Negative Effects ◽  
Tillage Systems ◽  
Soil Microbial

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

scholarly journals Perennial herbaceous legumes as live soil mulches and their effects on C, N and P of the microbial biomass

2003 ◽  
Vol 60 (1) ◽  
pp. 139-147 ◽  
Author(s):  
Gustavo Pereira Duda ◽  
José Guilherme Marinho Guerra ◽  
Marcela Teixeira Monteiro ◽  
Helvécio De-Polli ◽  
Marcelo Grandi Teixeira
Keyword(s):  
Microbial Biomass ◽  
Soil Depth ◽  
Vegetation Management ◽  
Pueraria Phaseoloides ◽  
Organic C ◽  
Arachis Pintoi ◽  
Factorial Combination ◽  
C And N ◽  
Microbial C ◽  
Macroptilium Atropurpureum

The use of living mulch with legumes is increasing but the impact of this management technique on the soil microbial pool is not well known. In this work, the effect of different live mulches was evaluated in relation to the C, N and P pools of the microbial biomass, in a Typic Alfisol of Seropédica, RJ, Brazil. The field experiment was divided in two parts: the first, consisted of treatments set in a 2 x 2 x 4 factorial combination of the following factors: live mulch species (Arachis pintoi and Macroptilium atropurpureum), vegetation management after cutting (leaving residue as a mulch or residue remotion from the plots) and four soil depths. The second part had treatments set in a 4 x 2 x 2 factorial combination of the following factors: absence of live mulch, A. pintoi, Pueraria phaseoloides, and M. atropurpureum, P levels (0 and 88 kg ha-1) and vegetation management after cutting. Variation of microbial C was not observed in relation to soil depth. However, the amount of microbial P and N, water soluble C, available C, and mineralizable C decreased with soil depth. Among the tested legumes, Arachis pintoi promoted an increase of microbial C and available C content of the soil, when compared to the other legume species (Pueraria phaseoloides and Macroptilium atropurpureum). Keeping the shoot as a mulch promoted an increase on soil content of microbial C and N, total organic C and N, and organic C fractions, indicating the importance of this practice to improve soil fertility.

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