scholarly journals Oxygen‐controlled recirculating seepage meter reveals extent of nitrogen transformation in discharging coastal groundwater at the aquifer–estuary interface

2021 ◽  
Author(s):  
Thomas Brooks ◽  
Kevin Kroeger ◽  
Holly Michael ◽  
Joanna York
Keyword(s):  
Nitrogen Transformation ◽  
Coastal Groundwater ◽  
Seepage Meter

Orientation of processes of biological nitrogen transformation in winter rye agroecosystems under different levels of fertilization background

2016 ◽  
Vol 3 (3) ◽  
pp. 28-34
Author(s):  
V. Volkogon ◽  
I. Korotka
Keyword(s):  
Root Zone ◽  
Field Studies ◽  
Nitrogen Transformation ◽  
Mineral Nitrogen ◽  
Nitrogen Fertilizers ◽  
Winter Rye ◽  
Podzolic Soils ◽  
Microbial Preparation ◽  
Biological Nitrogen

Aim. To determine physiologically expedient rates of mineral nitrogen in winter rye production on sod-podzol- ic soils based on the orientation of the processes of biological nitrogen transformation in the plants rhizosphere. Methods. Field studies, gas chromatography determination of potential nitrogen fi xation activity and potential emissions of N 2 O. Results. The results obtained have demonstrated that the rates of mineral nitrogen, not ex- ceeding 60 kg/ha, can be considered physiologically expedient for winter rye production on sod-podzolic soils. Under the application of microbial preparation Diazobakteryn, there is a higher physiological need of plants for nitrogen, which allows increasing the rates of nitrogen fertilizers up to 90 kg/ha. Conclusions. The orienta- tion of the processes of biological nitrogen transformation in the root zone of plants is a reliable indicator of determining the appropriateness of nitrogen fertilization of crops.

scholarly journals The Dynamic Response of Nitrogen Transformation to the Dissolved Oxygen Variations in the Simulated Biofilm Reactor

2021 ◽  
Vol 18 (7) ◽  
pp. 3633
Author(s):  
Qianqian Lu ◽  
Nannan Zhang ◽  
Chen Chen ◽  
Miao Zhang ◽  
Dehua Zhao ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Copy Number ◽  
Stable State ◽  
Quantitative Relationship ◽  
Nitrogen Transformation ◽  
Biofilm Reactor ◽  
Short Term ◽  
Nirs Gene ◽  
Biofilm Reactors ◽  
Recovery Times

Lab-scale simulated biofilm reactors, including aerated reactors disturbed by short-term aeration interruption (AE-D) and non-aerated reactors disturbed by short-term aeration (AN-D), were established to study the stable-state (SS) formation and recovery after disturbance for nitrogen transformation in terms of dissolved oxygen (DO), removal efficiency (RE) of NH4+-N and NO3−-N and activity of key nitrogen-cycle functional genes amoA and nirS (RNA level abundance, per ball). SS formation and recovery of DO were completed in 0.56–7.75 h after transition between aeration (Ae) and aeration stop (As). In terms of pollutant REs, new temporary SS formation required 30.7–52.3 h after Ae and As interruptions, and seven-day Ae/As interruptions required 5.0% to 115.5% longer recovery times compared to one-day interruptions in AE-D and AN-D systems. According to amoA activity, 60.8 h were required in AE-D systems to establish new temporary SS after As interruptions, and RNA amoA copies (copy number/microliter) decreased 88.5%, while 287.2 h were required in AN-D systems, and RNA amoA copies (copy number/microliter) increased 36.4 times. For nirS activity, 75.2–85.8 h were required to establish new SSs after Ae and As interruptions. The results suggested that new temporary SS formation and recovery in terms of DO, pollutant REs and amoA and nirS gene activities could be modelled by logistic functions. It is concluded that temporary SS formation and recovery after Ae and As interruptions occurred at asynchronous rates in terms of DO, pollutant REs and amoA and nirS gene activities. Because of DO fluctuations, the quantitative relationship between gene activity and pollutant RE remains a challenge.

Land-use type and temperature affect gross nitrogen transformation rates in Chinese and Canadian soils

2010 ◽  
Vol 334 (1-2) ◽  
pp. 377-389 ◽  
Author(s):  
Man Lang ◽  
Zu-Cong Cai ◽  
Bruno Mary ◽  
Xiying Hao ◽  
Scott X. Chang
Keyword(s):  
Land Use ◽  
Nitrogen Transformation ◽  
Land Use Type ◽  
Canadian Soils ◽  
Transformation Rates
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