Salinity affects the response of soil microbial activity and biomass to addition of carbon and nitrogen

Addition of carbon (C) and nitrogen (N) to soil can enhance microbial tolerance to salinity, but it is not known if salinity changes the response of microbial activity and biomass to addition of C and N, or how nutrient addition affects microbial tolerance to salinity. We prepared salinity treatments of non-saline soil [electrical conductivity (EC1 : 5) 0.1 dS m–1] without salt addition or adjusted to four salinity levels (2.5, 5.0, 7.5, 10 dS m–1) using a combination of CaCl2 and NaCl. The soils were amended with 2.5 mg C g–1 as glucose or as mature wheat straw (C/N ratio 47 : 1), with NH4Cl added to glucose to achieve a C/N ratio similar to that of wheat straw, or with NH4Cl added to glucose or wheat straw to achieve a C/N ratio of 20. Soil respiration was measured over 30 days. Microbial biomass C and N (MBC, MBN), dissolved organic C (DOC), and total dissolved N (TDN) were measured on day 30. Cumulative respiration and MBC concentration decreased with increasing EC, less so with glucose than with wheat straw. The MBC concentration was more sensitive to EC than was cumulative respiration, irrespective of C source. Addition of N to glucose and wheat straw to bring the C/N ratio to 20 significantly decreased cumulative respiration and MBC concentration at a given EC. This study showed that in the short term, addition of a readily available and easily decomposable source of energy improves the ability of microbes to tolerate salinity. The results also suggest that in saline soils, irrespective of the C substrate, N addition has no impact, or a negative impact, on microbial activity and growth.

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Management of sugarcane harvest residues: consequences for soil carbon and nitrogen

Soil Research ◽

10.1071/sr06080 ◽

2007 ◽

Vol 45 (1) ◽

pp. 13 ◽

Cited By ~ 83

Author(s):

Fiona A. Robertson ◽

Peter J. Thorburn

Keyword(s):

Microbial Biomass ◽

Soil Fertility ◽

Microbial Activity ◽

Soil N ◽

Soil Organic C ◽

Total N ◽

Organic C ◽

Soil Microbial ◽

C And N

The Australian sugar industry is moving away from the practice of burning the crop before harvest to a system of green cane trash blanketing (GCTB). Since the residues that would have been lost in the fire are returned to the soil, nutrients and organic matter may be accumulating under trash blanketing. There is a need to know if this is the case, to better manage fertiliser inputs and maintain soil fertility. The objective of this work was to determine whether conversion from a burning to a GCTB trash management system is likely to affect soil fertility in terms of C and N. Indicators of short- and long-term soil C and N cycling were measured in 5 field experiments in contrasting climatic conditions. The effects of GCTB varied among experiments. Experiments that had been running for 1–2 years (Harwood) showed no significant trash management effects. In experiments that had been running for 3–6 years (Mackay and Tully), soil organic C and total N were up to 21% greater under trash blanketing than under burning, to 0.10 or 0.25 m depth (most of this effect being in the top 50 mm). Soil microbial activity (CO2 production) and soil microbial biomass also increased under GCTB, presumably as a consequence of the improved C availability. Most of the trash C was respired by the microbial biomass and lost from the system as CO2. The stimulation of microbial activity in these relatively short-term GCTB systems was not accompanied by increased net mineralisation of soil N, probably because of the greatly increased net immobilisation of N. It was calculated that, with standard fertiliser applications, the entire trash blanket could be decomposed without compromising the supply of N to the crop. Calculations of possible long-term effects of converting from a burnt to a GCTB production system suggested that, at the sites studied, soil organic C could increase by 8–15%, total soil N could increase by 9–24%, and inorganic soil N could increase by 37 kg/ha.year, and that it would take 20–30 years for the soils to approach this new equilibrium. The results suggest that fertiliser N application should not be reduced in the first 6 years after adoption of GCTB, but small reductions may be possible in the longer term (>15 years).

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Effects of 17-year fertilization on soil microbial biomass C and N and soluble organic C and N in loessial soil during maize growth

Biology and Fertility of Soils ◽

10.1007/s00374-010-0511-7 ◽

2010 ◽

Vol 47 (2) ◽

pp. 121-128 ◽

Cited By ~ 68

Author(s):

Bin Liang ◽

Xueyun Yang ◽

Xinhua He ◽

Jianbin Zhou

Keyword(s):

Microbial Biomass ◽

Soil Microbial Biomass ◽

Microbial Biomass C ◽

Loessial Soil ◽

Organic C ◽

Soil Microbial Biomass C ◽

Soil Microbial ◽

Maize Growth ◽

C And N

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Soil CO2 respiration: Comparison of chemical titration, CO2 IRGA analysis and the Solvita gel system

Renewable Agriculture and Food Systems ◽

10.1017/s174217050800224x ◽

2008 ◽

Vol 23 (2) ◽

pp. 171-176 ◽

Cited By ~ 70

Author(s):

R.L. Haney ◽

W.F. Brinton ◽

E. Evans

Keyword(s):

Regression Analysis ◽

Microbial Activity ◽

Clay Content ◽

Soil Microbial Activity ◽

Gas Analysis ◽

Soil Samples ◽

Organic C ◽

Soil Microbial ◽

Highly Correlated ◽

Gel System

AbstractThe measurement of soil carbon dioxide respiration is a means to gauge biological soil fertility. Test methods for respiration employed in the laboratory vary somewhat, and to date the equipment and labor required have somewhat limited more widespread adoption of such methodologies. The purpose of this research is to compare the results of measured soil CO2 respiration using three methods: (1) titration method; (2) infrared gas analysis (IRGA); and (3) the Solvita gel system for soil CO2 analysis. We acquired 36 soil samples from across the USA for comparison, which ranged in pH from 4.5 to 8.5, organic C from 0.8 to 4.6% and the clay content from 6 to 62%. All three methods were highly correlated with each other after 24-h of incubation (titration and Solvita r2=0.82, respirometer and Solvita r2=0.79 and titration versus respirometer r2=0.95). The 24-h (1-day) CO2 release from all three methods was also highly correlated to both basal soil respiration (7–28 days) and cumulative 28-day CO2 respiration. An additional 24 soil samples were acquired and added to the original 36, for a total of 60 soil samples. These samples were used for calibration of the Solvita gel digital color reader results using CO2-titration results and regression analysis. Regression analysis resulted in the equation y=20.6∗(Solvita number)−16.5 with an r2 of 0.83. The data suggest that the Solvita gel system for soil CO2 analysis could be a simple and easily used method to quantify soil microbial activity. Applications may also exist for the gel system for in situ measurements in surface gas chambers. Once standardized soil sampling and laboratory analysis protocols are established, the Solvita method could be easily adapted to commercial soil testing labs as an index of soil microbial activity.

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Evaluation of Soil Microbial Activity and Maize (Zea mays L.) Growth in Soil Amended with Composted Agroindustrial Wastes

ISPEC Journal of Agricultural Sciences ◽

10.46291/ispecjasvol4iss2pp99-113 ◽

2020 ◽

Vol 4 (2) ◽

pp. 99-113

Author(s):

Huseyin Husnu KAYIKCIOGLU ◽

Nur OKUR

Keyword(s):

Microbial Activity ◽

Soil Microbial Activity ◽

The Other ◽

Maize Plant ◽

Control Soil ◽

Total N ◽

Organic C ◽

Amended Soils ◽

Soil Microbial ◽

Tobacco Waste

The present study was performed to emphasize that tobacco waste compost can be used as an organic material resource in soils under semi-arid climate conditions. We determined soil microbial activity as well as the contents of the nutrition and the biomass of maize plant to indicate which compost is the most suitable one for decomposing by microorganisms in the soil. In the greenhouse experiment, the treatments consisted of tobacco waste compost (TWC), tobacco waste+olive pomace compost (TWOPC), tobacco waste+grape pomace compost (TWGPC), tobacco waste+ farmyard manure compost (TWFYC), inorganic fertilization (NPK) and control soil. Soil respiration was higher in TWC amended soils, followed by TWOPC, TWGPC and TWFYC amended soils compared to non-amended soils. The effect of compost applications on enzyme activity of soil was significant. The activities of protease, urease and dehydrogenase were significantly higher in the soil amended with TWC as compared to those of the other composts. Β-Glucosidase activity was highest (21 %) in TWOPC with respect to control soil. Aryl sulphatase activity in the soils amended with the composts increased between 20 to 26 % with respect to the control. Activity of alkaline phosphatase in soils amended with the composts was not different from the amount obtained for control soil. The maximum values of leaf N, K and biomass weight of maize plant were found in inorganic fertilizer treatment (NPK). The biomass weight increased 115 % and 83 %, respectively, in NPK and TWC treatments compared to the control soil. The results suggested that application of the composts including tobacco waste to soil at a rate of 30 t ha-1 increased the amounts of microbial activity, organic C, available P and K in soil. On the other hand, the amount of total N in the composts is not enough for the growth of maize plant.

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Evaluating carbon dynamics and microbial activity in arctic soils under warmer temperatures

Canadian Journal of Soil Science ◽

10.4141/cjss07060 ◽

2008 ◽

Vol 88 (1) ◽

pp. 31-44 ◽

Cited By ~ 12

Author(s):

Maren Oelbermann ◽

Michael English ◽

Sherry L Schiff

Keyword(s):

Microbial Activity ◽

Soil Microorganisms ◽

Microbial Respiration ◽

Soil Microbial Activity ◽

Phase 2 ◽

Metabolic Diversity ◽

Soil Horizons ◽

Organic C ◽

Soil Microbial ◽

Arctic Soils

A large portion of carbon (C) is stored in the world’s soils, including those of peatlands, wetlands and permafrost. However, there is disagreement regarding the effects of climate change on the rate of organic matter decomposition in permafrost soils of the arctic. In this study it was hypothesized that soil exposed to a higher ambient temperature would have a greater flux of CO2 as well as a change in the metabolic diversity of culturable soil microorganisms. To evaluate this hypothesis we determined soil C dynamics, soil microbial respiration and activity, and 13C and 15N fractionation in laboratory incubations (at 14 and 21°C) for an organic-rich soil (Mesic Organic Cryosol) and a mineral soil (Turbic Cryosol) collected at the Daring Lake Research Station in Canada’s Northwest Territories. Soil organic C (SOC) and nitrogen (N) stocks (g m-2) and concentration (%) were significantly different (P < 0.05) between soil horizons for both soil types. Stable isotope analysis showed a significant enrichment in δ13C and δ15N with depth and a depletion in δ13C and δ15N with increasing SOC and N concentration. In laboratory incubations, microbial respiration showed three distinct phases of decomposition: a phase with a rapidly increasing rate of respiration (phase 1), a phase in which respiration reached a peak midway through the incubation (phase 2), and a phase in the latter part of the incubation in which respiration stabilized at a lower flux than that of the first phase (phase 3). Fluxes of CO2 were significantly greater at 21°C than at 14°C. The δ13C of the evolved CO2 became significantly enriched with time with the greatest enrichment occurring in phase 2 of the incubation. Soil microbial activity, as measured using Biolog EcoplatesTM, showed a significantly greater average well color development, richness, and Shannon index at 21°C; again the greatest change occurred in phase 2 of the incubation. Principal component analysis (PCA) of the Biolog data also showed a change in the distinct clustering of the soil microbial activity, showing that C sources from the soil were metabolized differently with time at 21 than at 14°C, and between soil horizons. Our results show that Canadian arctic soils contain large stores of C, which readily decompose, and that substantial increases in CO2 emissions and changes in the metabolic diversity of culturable soil microorganisms may occur when ambient temperatures increase from 14 to 21°C. Key words: CO2 flux, C fractionation, global warming, soil organic C and N, stable isotopes

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Effect of Water Potential, Temperature, and Soil Microbial Activity on Release of Starch‐Encapsulated Atrazine and Alachlor

Journal of Environmental Quality ◽

10.2134/jeq1992.00472425002100030013x ◽

1992 ◽

Vol 21 (3) ◽

pp. 382-386 ◽

Cited By ~ 15

Author(s):

Brian J. Wienhold ◽

Timothy J. Gish

Keyword(s):

Water Potential ◽

Microbial Activity ◽

Potential Temperature ◽

Soil Microbial Activity ◽

Soil Microbial ◽

Effect Of Water

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Forest defoliator pests alter carbon and nitrogen cycles

Royal Society Open Science ◽

10.1098/rsos.160361 ◽

2016 ◽

Vol 3 (10) ◽

pp. 160361 ◽

Cited By ~ 12

Author(s):

Anne l-M-Arnold ◽

Maren Grüning ◽

Judy Simon ◽

Annett-Barbara Reinhardt ◽

Norbert Lamersdorf ◽

...

Keyword(s):

Climate Change ◽

Leaf Litter ◽

Soil Microbial Activity ◽

Quercus Petraea ◽

Oak Forests ◽

Operophtera Brumata ◽

Winter Moth ◽

Carbon And Nitrogen ◽

Soil Microbial ◽

C And N

Climate change may foster pest epidemics in forests, and thereby the fluxes of elements that are indicators of ecosystem functioning. We examined compounds of carbon (C) and nitrogen (N) in insect faeces, leaf litter, throughfall and analysed the soils of deciduous oak forests ( Quercus petraea L.) that were heavily infested by the leaf herbivores winter moth ( Operophtera brumata L.) and mottled umber ( Erannis defoliaria L.). In infested forests, total net canopy-to-soil fluxes of C and N deriving from insect faeces, leaf litter and throughfall were 30- and 18-fold higher compared with uninfested oak forests, with 4333 kg C ha −1 and 319 kg N ha −1 , respectively, during a pest outbreak over 3 years. In infested forests, C and N levels in soil solutions were enhanced and C/N ratios in humus layers were reduced indicating an extended canopy-to-soil element pathway compared with the non-infested forests. In a microcosm incubation experiment, soil treatments with insect faeces showed 16-fold higher fluxes of carbon dioxide and 10-fold higher fluxes of dissolved organic carbon compared with soil treatments without added insect faeces (control). Thus, the deposition of high rates of nitrogen and rapidly decomposable carbon compounds in the course of forest pest epidemics appears to stimulate soil microbial activity (i.e. heterotrophic respiration), and therefore, may represent an important mechanism by which climate change can initiate a carbon cycle feedback.

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