Short-term N availability in response to dissolved-organic-carbon from poultry manure, alone or in combination with cellulose

1999 ◽  
Vol 29 (4) ◽  
pp. 386-393 ◽  
Author(s):  
P. Martín-Olmedo ◽  
R. M. Rees
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Poultry Manure ◽  
N Availability ◽  
Short Term

scholarly journals Carbon losses from pyrolysed and original wood in a forest soil under natural and increased N deposition

2014 ◽  
Vol 11 (18) ◽  
pp. 5199-5213 ◽  
Author(s):  
B. Maestrini ◽  
S. Abiven ◽  
N. Singh ◽  
J. Bird ◽  
M. S. Torn ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Forest Soil ◽  
N Deposition ◽  
Main Process ◽  
N Availability ◽  
N Losses ◽  
Mineral N ◽  
C Cycling ◽  
Carbon Losses

Abstract. Pyrogenic organic matter (PyOM) plays an important role as a stable carbon (C) sink in the soils of terrestrial ecosystems. However, uncertainties remain about in situ turnover rates of fire-derived PyOM in soil, the main processes leading to PyOM-C and nitrogen (N) losses from the soil, and the role of N availability on PyOM cycling in soils. We measured PyOM and native soil organic carbon losses from the soil as carbon dioxide and dissolved organic carbon (DOC) using additions of highly 13C-labelled PyOM (2.03 atom %) and its precursor pinewood during 1 year in a temperate forest soil. The field experiment was carried out under ambient and increased mineral N deposition (+60 kg N-NH4NO3 ha−1 year−1). The results showed that after 1 year: (1) 0.5% of PyOM-C and 22% of wood-C were mineralized as CO2, leading to an estimated turnover time of 191 and 4 years, respectively; (2) the quantity of PyOM and wood lost as dissolved organic carbon was negligible (0.0004 ± 0.0003% and 0.022 ± 0.007% of applied-C, respectively); and (3) N additions decreased cumulative PyOM mineralization by 43%, but did not affect cumulative wood mineralization and did not affect the loss of DOC from PyOM or wood. We conclude that mineralization to CO2 was the main process leading to PyOM losses during the first year of mineralization in a forest soil, and that N addition can decrease PyOM-C cycling, while added N showed no effect on wood C cycling.

scholarly journals Changes in Soil Organic Carbon Under Continuous Farming

2020 ◽  
Vol 7 (2) ◽  
pp. 175-181
Author(s):  
Izzah Abd Hamid ◽  
Wan Asrina Wan Yahaya ◽  
Norziana Zin Zawawi
Keyword(s):  
Organic Carbon ◽  
Soil Ph ◽  
Crop Residue ◽  
Flash Flood ◽  
Poultry Manure ◽  
N Availability ◽  
Soil System ◽  
Total N ◽  
Grid Sampling ◽  
Crop Uptake

Cultivating a land without proper crop management may lead to diminished organic carbon. Thus, this study assesses the effects of long-term farming (2014 to 2018) on soil OC. This study was conducted in Share Farm II, Universiti Putra Malaysia Bintulu Sarawak Campus on a selected area that practiced crop rotation. Soil samples have been collected according to grid sampling techniques by beds row and inter-row, and are analysed for soil pH, OM, TOC, and total N. The results show a trend in the alleviation of soil acidity with 2018 > 2016 > 2014, however, there is a diminished of TOC as the year of cultivation increases from 3.42% to 1.87%. The results show insufficient crop residue that returns to the soil system which has been subjected to flash flood and poultry manure application. In return, C retention ability was reduced, which further limit OM capability to supply nutrients upon decomposition. The correlation analysis has revealed that different types of crop residue such as grass clippings that have been applied in 2016 may be another reason for the insufficient N availability (0.44%). Therefore, the quantity and quality of residues may affect the decomposition rate and provide a lower C/N ratio, which significantly affects the soil pH, total N, and other nutrients that are essential for crop uptake. Res. Agric., Livest. Fish.7(2): 175-181,  August 2020

Short-Term Effects of Zooplankton Manipulations on Phosphate Uptake

1987 ◽  
Vol 44 (5) ◽  
pp. 1038-1044 ◽  
Author(s):  
Daniel T. Hamilton ◽  
William D. Taylor
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Phosphate Uptake ◽  
Phosphorus Uptake ◽  
Turnover Time ◽  
Relative Increase ◽  
Short Term ◽  
Nutrient Environment ◽  
Resource Levels

Samples of epilimnetic water were collected, manipulated to alter their zooplankton fauna, and incubated in situ for 24 h. We hypothesized that removal and concentration of zooplankton would decrease and increase phosphate turnover time, respectively, and that the presence of zooplankton would increase the accumulation of added 32PO4 by algae (particles greater than 1.0 μm) relative to bacteria (particles 0.2–1.0 μm). Although the treatments produced significant changes in turnover time and size distribution, neither hypothesis was supported; removal of zooplankton did not decrease turnover time, and it reduced the dominance of 0.2- to 1.0-μm particles in phosphorus uptake. However, concentrating microzooplankton frequently increased turnover time. Zooplankton removal caused a relative increase in ciliates, suggesting that these protozoa may be limited by their predators rather than by resource levels. Our results suggest that microzooplankton were the most important grazers and that the nutrient environment of phytoplankton was not directly affected by mesozooplankton. Phosphate dynamics were probably determined by bacteria, the protozoan predators of bacteria, and the supply of dissolved organic carbon.

Relationships between dissolved organic carbon concentrations, weather, and acidification in small Boreal Shield lakes

2008 ◽  
Vol 65 (5) ◽  
pp. 786-795 ◽  
Author(s):  
W. (Bill) Keller ◽  
Andrew M Paterson ◽  
Keith M Somers ◽  
Peter J Dillon ◽  
Jocelyne Heneberry ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Temporal Variation ◽  
Multiple Regression ◽  
Regression Models ◽  
Short Term ◽  
Multiple Regression Models ◽  
Boreal Shield ◽  
Shield Lakes

We used multiple linear regression analyses to explore empirical relationships between dissolved organic carbon (DOC) concentrations, weather, and acidification in long-term data sets from 12 small Boreal Shield lakes in Ontario, Canada. In two lakes in which pH changes have been very large (4.5 to ~6.0), pH explained most of the temporal variation in DOC concentrations. In the remaining lakes, long-term average previous temperature (on the scale of a decade or more) was usually the best explanatory variable for DOC concentrations. Lake-specific multiple regression models constructed from long-term and short-term attributes of weather (long-term average previous temperature and precipitation, winter–spring precipitation, summer precipitation, summer sunshine) and pH explained between 41% and 96% of the temporal variation in DOC concentrations during the entire monitoring period for these lakes (n = 16–26 years). Multiple regression models considering only the period common to all lakes, 1987 to 2003 (n = 16–17 years), explained 35%–96% of the variation in DOC concentrations. The importance of long-term and short-term attributes of weather in explaining temporal variations in DOC concentrations suggests that changes in climate will have large effects on lake clarity; however, the interactions between weather-related effects may be very complex.

scholarly journals Contrasting microbiome dynamics of putative denitrifying bacteria in two octocoral species exposed to dissolved organic carbon (DOC) and warming

2021 ◽  
Author(s):  
Nan Xiang ◽  
Christiane Hassenrück ◽  
Claudia Pogoreutz ◽  
Nils Rädecker ◽  
Susana Marcela Simancas-Giraldo ◽  
...  
Keyword(s):  
Microbial Community ◽  
Organic Carbon ◽  
Nutritional Status ◽  
Dissolved Organic Carbon ◽  
Bacterial Communities ◽  
Community Dynamics ◽  
Soft Coral ◽  
N Cycling ◽  
N Availability ◽  
Coral Holobiont

Mutualistic nutrient cycling in the coral-algae symbiosis depends on limited nitrogen (N) availability for algal symbionts. Denitrifying prokaryotes capable of reducing nitrate or nitrite to dinitrogen could thus support coral holobiont functioning by limiting N availability. Octocorals show some of the highest denitrification rates among reef organisms, however little is known about the community structures of associated denitrifiers and their response to environmental fluctuations. Combining 16S rRNA gene amplicon sequencing with nirS in-silico PCR and quantitative PCR, we found differences in bacterial community dynamics between two octocorals exposed to excess dissolved organic carbon (DOC) and concomitant warming. While bacterial communities of the gorgonian Pinnigorgia flava remained largely unaffected by DOC and warming, the soft coral Xenia umbellata exhibited a pronounced shift towards Alphaproteobacteria dominance under excess DOC. Likewise, the relative abundance of denitrifiers was not altered in P. flava , but decreased by one order of magnitude in X. umbellata under excess DOC likely due to decreased proportions of Ruegeria spp. Given that holobiont C:N ratios remained stable in P. flava but showed a pronounced increase with excess DOC in X. umbellata host, our results suggest that microbial community dynamics may reflect the nutritional status of the holobiont. Hence, denitrifier abundance may be directly linked to N availability. This suggests a passive regulation of N cycling microbes, which could help stabilize nutrient limitation in the coral-algal symbiosis and thereby support holobiont functioning in a changing environment. Importance Octocorals are important members of reef-associated benthic communities that can rapidly replace scleractinian corals as the dominant ecosystem engineers on degraded reefs. Considering the substantial change in the (a)biotic environment that is commonly driving reef degradation, maintaining a dynamic and metabolically diverse microbial community might contribute to octocoral acclimatization and ecological adaptation. Nitrogen (N) cycling microbes, in particular denitrifying prokaryotes, may support holobiont functioning by limiting internal N availability, but little is known about the identity and (a)biotic drivers of octocoral-associated denitrifiers. Here, we show contrasting dynamics of bacterial communities associated with two common octocoral species, the soft coral Xenia umbellata and the gorgonian Pinnigorgia flava after a six-week exposure to excess dissolved organic carbon (DOC) under concomitant warming conditions. The specific responses of denitrifier communities associated with the two octocoral species aligned with the nutritional status of holobiont members. This suggests a passive regulation of this microbial trait based on N availability in the coral holobiont.

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