scholarly journals Warming and Nitrogen Addition Change the Soil and Soil Microbial Biomass C:N:P Stoichiometry of a Meadow Steppe

Author(s):  
Gong ◽  
Zhang ◽  
Guo

: Soil and soil microbial biomass (SMB) carbon: nitrogen: phosphorus (C:N:P) stoichiometry are important parameters to determine soil balance of nutrients and circulation of materials, but how soil and SMB C:N:P stoichiometry is affected by climate change remains unclear. Field experiments with warming and N addition had been implemented since April 2007. Infrared radiators were used to manipulate temperature, and aqueous ammonium nitrate (10 g m-2 yr-1) was added to simulate nitrogen deposition. We found that molar nutrient ratios in the soil averaged 60:11:1, warming and warming plus N addition reduced soil C:N by 14.1% and 20% (P < 0.01), and reduced soil C:P ratios by 14.5% and 14.8% (P < 0.01). N addition reduced soil C:N significantly by 17.6% (P < 0.001) (Figs. 2B, 2D). N addition and warming plus N addition increased soil N:P significantly by 24.6% and 7.7% (P < 0.01). The SMB C:N, C:P and N:P ratios increased significantly with warming, N addition and warming plus N addition. Warming and N addition increased the correlations between SOC and soil microbial biomass C (SMBC), soil total P and soil microbial biomass P (SMBP), warming increased the correlation between the soil total N and soil microbial biomass N (SMBN). After four years’ treatment, our results demonstrated that the combined effects of warming and N fertilization could change the C, N, P cycling by affecting soil and SMB C:N:P ratios significantly and differently. At the same time, our results suggested SMB might have weak homeostasis in Sonnen Grassland and warming and N addition would ease N-limitation but aggravate P-limitation in northeastern China. Furthermore, these results further the current demonstration of the relationships between the soil and SMB C:N:P stoichiometry in response to global change in temperate grassland ecosystems.

Agronomy ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2057
Author(s):  
Sehrish Ali ◽  
Kailou Liu ◽  
Waqas Ahmed ◽  
Huang Jing ◽  
Muhammad Qaswar ◽  
...  

A long-term experiment (38 years) was conducted to elucidate the effects of long-term N addition on the net N mineralization in both paddy and upland soils, based on their initial soil N status, with and in connection with soil microbial biomass and N cycling extracellular enzyme activities. Two treatments without N addition CK (No fertilizer) and K (inorganic potassium fertilizer) and two treatments with N addition N (inorganic nitrogen fertilizer) and NK (inorganic nitrogen and potassium fertilizer) were placed in incubation for 90 days. Results showed that the total N and soil organic carbon (SOC) contents were higher in the treatments with N application compared to the treatments without N in both paddy and upland soils. The SOC content of paddy soil was increased relative to upland soil by 56.2%, 45.7%, 61.1% and 62.2% without N (CK, K) and with N (N and NK) treatments, respectively. Site-wise, total N concentration in paddy soil was higher by 0.06, 0.10, 0.57 and 0.60 times under the CK, K, N and NK treatments, respectively, compared with upland soil. In paddy soil, soil microbial biomass nitrogen (SMBN) was higher by 39.6%, 2.77%, 29.5% and 31.4%, and microbial biomass carbon (SMBC) was higher by 11.8%, 11.9%, 10.1% and 12.3%, respectively, in CK, K, N and NK treatment, compared with upland soil. Overall, compared to upland soil, the activities of leucine-aminopeptidase (LAP) were increased by 31%, 18%, 20% and 11%, and those of N-acetyl-b-D-glucosaminidase (NAG) were increased by 70%, 21%, 13% and 18% by CK, K, N and NK treatments, respectively, in paddy soil. A significantly linear increase was found in the NO3−-N and NH4+-N concentrations during the 90 days of the incubation period in both soils. NK treatment showed the highest N mineralization potential (No) along with mineralization rate constant, k (NMR) at the end of the incubation. SMBC, SMBN, enzyme activities, NO3−-N and NH4+-N concentrations and the No showed a highly significant (p ≤ 0.05) positive correlation. We concluded that long-term N addition accelerated the net mineralization by increasing soil microbial activities under both soils.


Agriculture ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 596
Author(s):  
Giancarlo Renella

Recovery of soil fertility after de-sealing of urban soils is still poorly known. This work studied the time-related dynamics of soil physico-chemical and biochemical endpoints of urban soil in the city in Naples (Southern Italy), de-sealed for different time during construction works, that underwent colonization by volunteer plants. The results showed de-sealing decreased the soil bulk density and the soil pH value, increased the electrical conductivity (EC), total organic C (TOC) and extractable carbohydrates (TEC), total and inorganic N contents, soil basal respiration (SBR), soil microbial biomass C (MBC) and soil microbial biomass N (MBN), the substrate induced respiration (SIR) value, and enzyme activities involved in C, N, P and S mineralization. The TEC, total and inorganic N, SBR and microbial biochemical endpoints were higher in the de-sealed soils than those of an arable soil of the same area. The results show that de-sealed urban soils rapidly increase their physical, chemical and biological fertility even with no intervention, especially when they are colonized by volunteer plants.


2011 ◽  
Vol 1 (4) ◽  
pp. 202-207
Author(s):  
N. Ewusi‐Mensah ◽  
V. Logah ◽  
J. O. Fening

This paper reports the short Ã¢â‚¬Â term effects of organic and inorganic fertilizerapplications on the culturable resident bacterial and fungal properties of aFerric Acrisol in the semi Ã¢â‚¬Âdeciduous forest zone of Ghana after three continuouscropping seasons. The treatments were two compost types (i.e. 1:1compost comprising 1 part made up of Chromolaena, Stylosanthes, maizestover mixture and 1 part of cattle manure, 2:1 compost comprising 2 partsof Chromolaena, Stylosanthes, maize stover mixture and 1 part of cattle manure),cowdung, 100% NPK and a control replicated three times in a randomizedcomplete block design. The results showed that total microbial load on alogarithmic scale ranged from 4.6 cfu/g in the control to 5.4 on cowdungtreated plots. Bacterial counts on 2:1 compost applied at 5 t/ha treatedplots recorded 5% more bacteria than the 1:1 compost applied at 5 t/ha.Fungal counts in the control and inorganic treated plots were higher than theorganically amended plots. The highest and lowest microbial biomass C contentswere recorded on cowdung and 1:1 compost at 5 t/ha treated plotsrespectively. Microbial biomass N content ranged from 1.4 Ã¢â‚¬Â 8.2 mg N kg‐1soil with a mean value of 6.2 mg N kg Ã¢â‚¬Â1 soil. Microbial biomass P contentranged from 3.6 Ã¢â‚¬Â 6.3 mg P kg‐1 soil with a mean value of 5 mg P kg‐1 soil.Microbial biomass carbon to organic carbon ratio varied from 18.37 to 85.63.


1998 ◽  
Vol 78 (2) ◽  
pp. 283-290 ◽  
Author(s):  
P. Rochette ◽  
E. G. Gregorich

Application of manure and fertilizer affects the rate and extent of mineralization and sequestration of C in soil. The objective of this study was to determine the effects of 3 yr of application of N fertilizer and different manure amendments on CO2 evolution and the dynamics of soil microbial biomass and soluble C in the field. Soil respiration, soluble organic C and microbial biomass C were measured at intervals over the growing season in maize soils amended with stockpiled or rotted manure, N fertilizer (200 kg N ha−1) and with no amendments (control). Manure amendments increased soil respiration and levels of soluble organic C and microbial biomass C by a factor of 2 to 3 compared with the control, whereas the N fertilizer had little effect on any parameter. Soil temperature explained most of the variations in CO2 flux (78 to 95%) in each treatment, but data from all treatments could not be fitted to a unique relationship. Increases in CO2 emission and soluble C resulting from manure amendments were strongly correlated (r2 = 0.75) with soil temperature. This observation confirms that soluble C is an active C pool affected by biological activity. The positive correlation between soluble organic C and soil temperature also suggests that production of soluble C increases more than mineralization of soluble C as temperature increases. The total manure-derived CO2-C was equivalent to 52% of the applied stockpiled-manure C and 67% of the applied rotted-manure C. Estimates of average turnover rates of microbial biomass ranged between 0.72 and 1.22 yr−1 and were lowest in manured soils. Manured soils also had large quantities of soluble C with a slower turnover rate than that in either fertilized or unamended soils. Key words: Soil respiration, greenhouse gas, soil carbon


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.


2004 ◽  
Vol 40 (3-4) ◽  
pp. 113-121 ◽  
Author(s):  
A.R. Barbhuiya ◽  
A. Arunachalam ◽  
H.N. Pandey ◽  
K. Arunachalam ◽  
M.L. Khan ◽  
...  

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