Decrease in soil microbial activity and biomasses owing to nitrogen amendments

1983 ◽  
Vol 29 (11) ◽  
pp. 1500-1506 ◽  
Author(s):  
B. Söderström ◽  
E. Bååth ◽  
B. Lundgren

Microbial biomass and soil respiration rate decreased after application of 150 kg NH4NO3–N∙ha−1 to different coniferous forest podzols. The decrease was already found 3 months after fertilization and was still evident after 3–5 years. Changes in pH, organic matter, or water content in the soils could not explain the decreases. In laboratory experiments, several unfertilized forest soils were treated with 2 mg of NH4NO3–N or of urea–nitrogen∙g wet soil−1. The ammonium nitrate addition resulted in severe depressions of the respiration rates during and up to 175 days of incubation and the decrease was evident after about 1 week. The urea treatment initially increased the respiration rate of the soils, but this appeared to be a transitory effect.

Author(s):  
Beata Klimek ◽  
Hanna Poliwka-Modliborek ◽  
Irena M. Grześ

AbstractInteractions between soil fauna and soil microorganisms are not fully recognized, especially in extreme environments, such as long-term metal-polluted soils. The purpose of the study was to assess how the presence of Lasius niger ants affected soil microbial characteristics in a long-term metal-polluted area (Upper Silesia in Poland). Paired soil samples were taken from bulk soil and from ant nests and analysed for a range of soil physicochemical properties, including metal content (zinc, cadmium, and lead). Microbial analysis included soil microbial activity (soil respiration rate), microbial biomass (substrate-induced respiration rate), and bacteria catabolic properties (Biolog® ECO plates). Soil collected from ant nests was drier and was characterized by a lower content of organic matter, carbon and nitrogen contents, and also lower metal content than bulk soil. Soil microbial respiration rate was positively related to soil pH (p = 0.01) and negatively to water-soluble metal content, integrated into TIws index (p = 0.01). Soil microbial biomass was negatively related to TIws index (p = 0.04). Neither soil microbial activity and biomass nor bacteria catabolic activity and diversity indices differed between bulk soil and ant nests. Taken together, ant activity reduced soil contamination by metals in a microscale which support microbial community activity and biomass but did not affect Biolog® culturable bacteria.


Agriculture ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 244 ◽  
Author(s):  
Kerstin Nielsen ◽  
Christina-Luise Roß ◽  
Marieke Hoffmann ◽  
Andreas Muskolus ◽  
Frank Ellmer ◽  
...  

Digestates are commonly used as organic inputs in agriculture. This study aimed to answer four questions: (1) What are the immediate and longer-term impacts of digestates on soil microbial activity?; (2) How much of the digestates’ carbon is mineralized within the first months? (3) How do the nitrogen, lignin, cellulose, and hemicellulose contents of digestates influence microbial activity and carbon mineralization? (4) How does the soil type influence mineralization? To investigate this, dehydrogenase activity (DHA) was measured in a field trial and in laboratory experiments with five digestates (DGs), cattle slurry, and cattle manure. DHA measurements were supplemented with soil respiration experiments using two different soils. DHA was significantly increased by all organic inputs, but decreased back to the control level within seven months under field conditions. Twenty percent to 44% of the organic carbon (Corg) in the digestates was converted to CO2 after 178 days. Soil respiration was significantly negatively correlated to lignin content (r = −0.82, p < 0.01) and not correlated to nitrogen, cellulose, or hemicellulose content. On the basis of equal carbon application, slurry promoted soil respiration and DHA more strongly than digestates in the short term.


1990 ◽  
Vol 20 (7) ◽  
pp. 910-913 ◽  
Author(s):  
P. O. Salonius

Organic soil materials from a spruce forest were submitted to simulated rain of pH 2.6, 3.6, 4.6, and 5.6. Marked decreases in soil microbial activity were found only with pH 2.6 rain, but responsiveness to increasing temperature was lower as rain of greater acidity was applied to the soil. Ammonium nitrogen mineralization rates were not affected by treatment of soil with acidified precipitation.


1960 ◽  
Vol XXXIII (III) ◽  
pp. 428-436 ◽  
Author(s):  
W. N. Holmes

ABSTRACT Relatively large doses of vasopressin administered intraperitoneally to the trout significantly enhanced the kidney respiration rate. In contrast to vasopressin a single dose of oxytocin depressed the kidney Qo2 value. This depression continued throughout the observed 24 hour period after injection. Cortisol enhanced the kidney Qo2 values significantly and to a greater extent than vasopressin. These results are discussed in relation to possible adaptive mechanism in euryhaline species of teleosts.


1992 ◽  
Vol 26 (5-6) ◽  
pp. 1355-1363 ◽  
Author(s):  
C-W. Kim ◽  
H. Spanjers ◽  
A. Klapwijk

An on-line respiration meter is presented to monitor three types of respiration rates of activated sludge and to calculate effluent and influent short term biochemical oxygen demand (BODst) in the continuous activated sludge process. This work is to verify if the calculated BODst is reliable and the assumptions made in the course of developing the proposed procedure were acceptable. A mathematical model and a dynamic simulation program are written for an activated sludge model plant along with the respiration meter based on mass balances of BODst and DO. The simulation results show that the three types of respiration rate reach steady state within 15 minutes under reasonable operating conditions. As long as the respiration rate reaches steady state the proposed procedure calculates the respiration rate that is equal to the simulated. Under constant and dynamic BODst loading, the proposed procedure is capable of calculating the effluent and influent BODst with reasonable accuracy.


2016 ◽  
Vol 3 (10) ◽  
pp. 160361 ◽  
Author(s):  
Anne l-M-Arnold ◽  
Maren Grüning ◽  
Judy Simon ◽  
Annett-Barbara Reinhardt ◽  
Norbert Lamersdorf ◽  
...  

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.


Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 665
Author(s):  
Ladislav Holik ◽  
Jiří Volánek ◽  
Valerie Vranová

Soil proteases are involved in organic matter transformation processes and, thus, influence ecosystem nutrient turnovers. Phytohormones, similarly to proteases, are synthesized and secreted into soil by fungi and microorganisms, and regulate plant rhizosphere activity. The aim of this study was to determine the effect of auxins, cytokinins, ethephon, and chlorocholine chloride on spruce forest floor protease activity. It was concluded that the presence of auxins stimulated native proteolytic activity, specifically synthetic auxin 2-naphthoxyacetic acid (16% increase at added quantity of 5 μg) and naturally occurring indole-3-acetic acid (18%, 5 μg). On the contrary, cytokinins, ethephon and chlorocholine chloride inhibited native soil protease activity, where ethephon (36% decrease at 50 μg) and chlorocholine chloride (34%, 100 μg) showed the highest inhibitory effects. It was concluded that negative phytohormonal effects on native proteolytic activity may slow down organic matter decomposition rates and hence complicate plant nutrition. The study enhances the understanding of rhizosphere exudate effects on soil microbial activity and soil nitrogen cycle.


2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
A. Marais ◽  
M. Hardy ◽  
M. Booyse ◽  
A. Botha

Different plants are known to have different soil microbial communities associated with them. Agricultural management practices such as fertiliser and pesticide addition, crop rotation, and grazing animals can lead to different microbial communities in the associated agricultural soils. Soil dilution plates, most-probable-number (MPN), community level physiological profiling (CLPP), and buried slide technique as well as some measured soil physicochemical parameters were used to determine changes during the growing season in the ecosystem profile in wheat fields subjected to wheat monoculture or wheat in annual rotation with medic/clover pasture. Statistical analyses showed that soil moisture had an over-riding effect on seasonal fluctuations in soil physicochemical and microbial populations. While within season soil microbial activity could be differentiated between wheat fields under rotational and monoculture management, these differences were not significant.


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