scholarly journals Pesticides effect on soil microbial ecology and enzyme activity- An overview

2016 ◽  
Vol 8 (2) ◽  
pp. 1126-1132 ◽  
Author(s):  
Sanjay Arora ◽  
Divya Sahni
Keyword(s):  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
Soil Microbes ◽  
Microbial Biomass Carbon ◽  
Soil Microbial Communities ◽  
Field Application ◽  
Microbial Biomass C ◽  
Microbial Biomass Nitrogen ◽  
Soil Microbial ◽  
Chemical Pesticides

In modern agriculture, chemical pesticides are frequently used in agricultural fields to increase crop production. Besides combating insect pests, these insecticides also affect the activity and population of beneficial soil microbial communities. Chemical pesticides upset the activities of soil microbes and thus may affect the nutritional quality of soils. This results in serious ecological consequences. Soil microbes had different response to different pesticides. Soil microbial biomass that plays an important role in the soil ecosystem where they have crucial role in nutrient cycling. It has been reported that field application of glyphosate increased microbial biomass carbon by 17% and microbial biomass nitrogen by 76% in nine soils at 14 days after treatment. The soil microbial biomass C increased significantly upto 30 days in chlorpyrifos as well as cartap hydrochloride treated soil, but thereafter decreased progressively with time. Soil nematodes, earthworms and protozoa are affected by field application rates of the fungicide fenpropimorph and other herbicides. Thus, there is need to assess the effect of indiscriminate use of pesticides on soil microorganisms, affecting microbial activity and soil fertility.

scholarly journals Effects of liming on the microbial biomass and its activities in soils long-term contaminated by toxic elements

2011 ◽  
Vol 52 (No. 8) ◽  
pp. 345-352 ◽  
Author(s):  
G. Mühlbachová ◽  
P. Tlustoš
Keyword(s):  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
Respiratory Activity ◽  
Soil Microbial Communities ◽  
Microbial Biomass C ◽  
Negative Effects ◽  
Lead Smelter ◽  
Soil Microbial ◽  
Hydrogen Carbonates

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.

Seasonal Dynamics of Soil Microorganism in Zhalong Reed Wetland

2011 ◽  
Vol 71-78 ◽  
pp. 2992-2998
Author(s):  
Ling Ma ◽  
Sheng Nan Liu ◽  
Xin Hua Ding ◽  
Wei Ma
Keyword(s):  
Microbial Biomass ◽  
Seasonal Dynamics ◽  
Soil Microbial Biomass ◽  
Soil Microbes ◽  
Microbial Biomass Carbon ◽  
Organic Carbon Content ◽  
Biomass Carbon ◽  
Carbon And Nitrogen ◽  
Soil Microbial ◽  
Soil Microbial Biomass Carbon

In this paper, the spatial distributions and seasonal dynamics of soil microbes and microbial biomass were investigated in a typical reed marsh in Zhalong natural wetlands.We wanted to explore the main factors that impacted their spatio-temporal patterns. The results showed that: Bacteria were dominant, followed by actinomyces and fungi were at least in the soil microbes community. The seasonal dynamics of soil microbial biomass carbon and nitrogen were more regularly, and their change patterns were significantly as "W" types. The response of soil microbial biomass in Bottom (10-30cm) to time was slower than the surface, and it fluctuated tinily in every months. The correlation analysis shows that the soil nutrient and soil microbial activity had close relationship. Soil microbial biomass carbon and nitrogen were all significantly positively correlated to quantities of fungus, organic carbon content and Alkali-hytrolyzabel N content(P<0.01), but negative extremely significantly correlated with pH (P<0.01).

scholarly journals Effects of Wildfire and Harvest Disturbances on Forest Soil Bacterial Communities

2007 ◽  
Vol 74 (1) ◽  
pp. 216-224 ◽  
Author(s):  
Nancy R. Smith ◽  
Barbara E. Kishchuk ◽  
William W. Mohn
Keyword(s):  
Microbial Biomass ◽  
Microbial Communities ◽  
Community Composition ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Microbial Biomass Carbon ◽  
Bacterial Community Composition ◽  
Soil Microbial Communities ◽  
Rrna Gene ◽  
Microbial Biomass Nitrogen ◽  
Soil Microbial

ABSTRACT Wildfires and harvesting are important disturbances to forest ecosystems, but their effects on soil microbial communities are not well characterized and have not previously been compared directly. This study was conducted at sites with similar soil, climatic, and other properties in a spruce-dominated boreal forest near Chisholm, Alberta, Canada. Soil microbial communities were assessed following four treatments: control, harvest, burn, and burn plus timber salvage (burn-salvage). Burn treatments were at sites affected by a large wildfire in May 2001, and the communities were sampled 1 year after the fire. Microbial biomass carbon decreased 18%, 74%, and 53% in the harvest, burn, and burn-salvage treatments, respectively. Microbial biomass nitrogen decreased 25% in the harvest treatment, but increased in the burn treatments, probably because of microbial assimilation of the increased amounts of available NH4 + and NO3 − due to burning. Bacterial community composition was analyzed by nonparametric ordination of molecular fingerprint data of 119 samples from both ribosomal intergenic spacer analysis (RISA) and rRNA gene denaturing gradient gel electrophoresis. On the basis of multiresponse permutation procedures, community composition was significantly different among all treatments, with the greatest differences between the two burned treatments versus the two unburned treatments. The sequencing of DNA bands from RISA fingerprints revealed distinct distributions of bacterial divisions among the treatments. Gamma- and Alphaproteobacteria were highly characteristic of the unburned treatments, while Betaproteobacteria and members of Bacillus were highly characteristic of the burned treatments. Wildfire had distinct and more pronounced effects on the soil microbial community than did harvesting.

Changes in soil carbon and nitrogen under long-term cotton plantations in China

2011 ◽  
Vol 149 (4) ◽  
pp. 497-505 ◽  
Author(s):  
W. KAIYONG ◽  
F. HUA ◽  
T. RANAB ◽  
M. A. HANJRAC ◽  
D. BO ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
Microbial Biomass Carbon ◽  
Soil Layer ◽  
Control Site ◽  
Available Nitrogen ◽  
Microbial Biomass Nitrogen ◽  
Effective Measure ◽  
Soil Microbial ◽  
Time Substitution

SUMMARYCotton is the dominant crop in the northern Xinjiang oasis of China; it accounts for 0·78 of the total planting area and represents a major contribution to economic development. The objective of the present study is to determine how cotton plantation age affected chemical and microbiological properties of the soil. The time substitution method was used on plantation farmlands, reclaimed from uncultivated land 0, 5, 10, 15 and 20 years ago. A total of 250 soil samples, at depths of 0–200, 200–400, 400–600, 600–800 and 800–1000 mm, were collected from cotton fields in 10 farms of each age category. There were significant differences in soil organic carbon (SOC), total soil nitrogen (TSN), soil available nitrogen (SAN), soil microbial biomass carbon (SMBC) and soil microbial biomass nitrogen (SMBN). There were also differences in the activities of cellulase, invertase and urease between soil layers and plantation ages, and these were most evident in the 200–400 mm layer. The cumulative rates of SOC and SMBC in the 0–1000 mm soil layer at the 5-, 10-, 15- and 20-year sites were 0·89, 0·99, 1·01 and 0·92 mg/kg/yr and 16, 16, 16 and 15 mg/kg/yr, respectively, compared to that at the control site (0 year). The cumulative amounts of SOC and SMBC increased gradually and then decreased, reaching a maximum at plantation ages of 13·1 years and 11·1 years, respectively. This suggests that incorporation of post-harvest cotton residues could be used as an effective measure to improve SOC in farmland of Xinjiang Oasis, and may be recommended for adoption in cotton growing in semi-arid oasis agriculture.

scholarly journals Effects of Biochar and Straw Application on the Physicochemical and Biological Properties of Paddy Soils in Northeast China

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yu Zheng ◽  
Xiaori Han ◽  
Yuying Li ◽  
Jinfeng Yang ◽  
Na Li ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Soil Quality ◽  
Northeast China ◽  
Soil Microbial Biomass ◽  
Microbial Biomass Carbon ◽  
Chemical Fertilizer ◽  
Microbial Biomass Nitrogen ◽  
Effective Measure ◽  
Soil Microbial ◽  
Straw Application

Abstract Applying biochar to soil has been proposed as a strategy to enhance soil quality and crop productivity. To further evaluate the influence of biochar and straw application on soil fertility and crop yield, a five-year fixed site field experiment was conducted in a paddy field in Northeast China. The experimental design included six treatments: control (CK), biochar (C), straw (S), chemical fertilizers (NPK), biochar with chemical fertilizer (CNPK) and straw with chemical fertilizer (SNPK). The results showed that compared with the NPK treatment, CNPK and SNPK significantly increased soil total porosity, soil air permeability coefficient, soil organic carbon (SOC), C/N ratio, soil microbial biomass carbon (SMBC)‚ soil microbial biomass nitrogen (SMBN), invertase activity and rice yield. Furthermore, amendment of biochar had a better effect on SOC, C/N ratio, SMBC, and SMBN than that of straw. In addition, SMBC, SOC, and total nitrogen (TN) had significant correlations with soil enzyme activities. Therefore, amendment of biochar with chemical fertilizer is an effective measure to improve rice production and soil quality in the northeast of China.

scholarly journals Microbial responses to doses of cover plant straw in cerrado piauiense oxisol

2020 ◽  
Vol 36 (4) ◽  
Author(s):  
Sarah Priscilla do Nascimento Amorim ◽  
Cacio Luiz Boechat ◽  
Lizandra de Sousa Luz Duarte ◽  
Daniela Fernandes de Oliveira ◽  
João Carlos Medeiros ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
Microbial Population ◽  
Microbial Biomass Carbon ◽  
Basal Respiration ◽  
Microbial Biomass C ◽  
Biomass Carbon ◽  
Carbon And Nitrogen ◽  
Soil Microbial ◽  
Soil Basal Respiration

Carbon and nitrogen from the soil microbial biomass play a significant role in the rotation of C and N, and promote nutrient cycling. Thus, the objective of this study was to evaluate changes in the soil microbial biomass with growing doses of cover plant straw species. The cover plants cultivated in the cerrado biome region were incorporated an Oxisol Ustox. The straw of each cover plant was incorporated at doses of 0; 10; 20 and 30 Mg ha-1. The soil basal respiration was determined by incubating, after 21 days. The microbial biomass carbon and nitrogen were determined by the method the microwave irradiation. The microbial biomass carbon and nitrogen contents in extracts were determined by the wet combustion method and Kjeldahl-N. The metabolic quotient was calculated as the ratio between soil basal respiration rate and microbial biomass C, and the microbial quotient as the ratio between soil microbial biomass C and total carbon of soil. The soil microbial population measured by the attributes of quality responds to the addition of the of grass and legume straws incorporated to the soil; The treatments that cause the greatest stress to the microbial population, at 21 days, mediated by the metabolic quotient, are guandu-anão at a dose of 10 Mg ha-1; Guandu-anão and Guandu fava-larga at 20 Mg ha-1 and Brachiária at a dose of 30 Mg ha-1; The best result regarding microbial attributes of soil quality evaluated was observed with the incorporation of all doses of the straw of Crotalaria-ocroleuca.  

scholarly journals Characteristics and Environmental Factors of Stoichiometric Homeostasis of Soil Microbial Biomass Carbon, Nitrogen and Phosphorus in China

2019 ◽  
Vol 11 (10) ◽  
pp. 2804 ◽  
Author(s):  
Haili Xue ◽  
Xiao Lan ◽  
Haoguang Liang ◽  
Qin Zhang
Keyword(s):  
Microbial Biomass ◽  
Environmental Factors ◽  
Soil Microbial Biomass ◽  
Soil Microbes ◽  
Microbial Biomass Carbon ◽  
Soil Layer ◽  
N:P Ratio ◽  
Soil Microbial ◽  
C:N:P Ratio ◽  
Wide Range

Marine studies have shown that the carbon:nitrogen:phosphorus (C:N:P) atomic ratio in planktonic organisms is generally 106:16:1, which is known as the “Redfield ratio”. This raises the question of whether there are similar patterns in terrestrial organisms, particularly in soil. In this study, we extracted 404 datasets from the literature to analyze the ecological stoichiometry of C, N and P, both in the soil and in the soil microbial biomass in China; additionally, we assessed their relationships with environmental factors, and calculated the homeostasis coefficient (H) of soil microbial biomass. First, although the concentrations of C, N and P in soil and soil microbial biomass showed high spatial heterogeneity, the atomic C:N:P ratios in the soil and soil microbial biomass were relatively consistent at the national scale. Second, the influences of temperature and precipitation on stoichiometric relationships among C, N and P in the soil and soil microbial biomass were limited in China; however, they decreased with the increase in soil pH. Third, the degree of stoichiometric homeostasis for soil microbes spanned a wide range, from non-homeostasis to strict homeostasis. For single elements, most of the soil microbes’ H ranged from 1.01 to 5.00; for elemental ratios, most of the soil microbes’ H displayed strict homeostasis. This study indicates that the “Redfield-like” ratio exists in the soil microbial biomass in the 0–20 cm soil layer in China, with an atomic C:N:P ratio of 66:8:1 and it is close to the atomic C:N:P ratio in the soil (66:5:1) of terrestrial ecosystems. In addition to the N:P ratio in plants, the soil microbial biomass N:P ratio may also be used to judge the nutrient limitations because of its high stability.

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