scholarly journals Pollution Swapping of N<sub>2</sub>O and CH<sub>4 </sub>Emissions with Dissolved Nitrogen and Phosphorus Export in Drainage Water Managed Agricultural Fields

2020 ◽  
Author(s):  
Jacob Hagedorn ◽  
Eric Davidson ◽  
Rebecca Fox ◽  
Erika Koontz ◽  
Thomas Fisher ◽  
...  
Keyword(s):  
Drainage Water ◽  
Agricultural Fields ◽  
Nitrogen And Phosphorus ◽  
Dissolved Nitrogen ◽  
Phosphorus Export

scholarly journals Land‐use dominates climate controls on nitrogen and phosphorus export from managed and natural Nordic headwater catchments

2020 ◽  
Vol 34 (25) ◽  
pp. 4831-4850
Author(s):  
Heleen A. Wit ◽  
Ahti Lepistö ◽  
Hannu Marttila ◽  
Hannah Wenng ◽  
Marianne Bechmann ◽  
...  
Keyword(s):  
Land Use ◽  
Nitrogen And Phosphorus ◽  
Headwater Catchments ◽  
Climate Controls ◽  
Phosphorus Export

Long-Term Observations of Nitrogen and Phosphorus Export in Paired-Agricultural Watersheds under Controlled and Conventional Tile Drainage

2015 ◽  
Vol 44 (5) ◽  
pp. 1589-1604 ◽  
Author(s):  
M. D. Sunohara ◽  
N. Gottschall ◽  
G. Wilkes ◽  
E. Craiovan ◽  
E. Topp ◽  
...  
Keyword(s):  
Tile Drainage ◽  
Agricultural Watersheds ◽  
Nitrogen And Phosphorus ◽  
Phosphorus Export

scholarly journals Nitrogen Movement and Leaching in Soil

1976 ◽  
Vol 7 (1) ◽  
pp. 19-30 ◽  
Author(s):  
H. E. Jensen
Keyword(s):  
Soil Water ◽  
Field Experiments ◽  
Nitrogen Concentration ◽  
Agricultural Practices ◽  
Field Capacity ◽  
Drainage Water ◽  
Climate Conditions ◽  
Dissolved Nitrogen ◽  
Lysimeter Experiment ◽  
Soil Climate

Movement and leaching of residual nitrogen in soil has been studied in some details in a lysimeter experiment. Profile measurements of soil water and of nitrogen concentration in addition to measurements of amount and composition of the drainage water were carried out. The leaching process could be described by an equation of Day. For a flow rate of approximately 1 cm/day, a dispersion coefficient of 11.5 cm2/day was obtained independent of the concentration level. Using this value, the equation satisfactorily predicted concentration of nitrogen and leached amount of nitrogen in the drainage water. The equation, although the assumptions inherent in the theory are not completely fulfilled, may therefore be used for predictive purposes under field conditions. An excess of precipitation, approximately equal to field capacity, is predicted necessary for leaching 50 per cent of an amount of dissolved nitrogen initially localized at the surface of the soil. Consequently, under many soil/climate conditions, the composition of drainage water is influenced by agricultural practices from previous years, which makes difficult interpretation of the results. This has been illustrated by relating some available data on drainage water quality from field experiments to the concentration of nitrogen in the soil water, as predicted by the theory.

scholarly journals Distributions and stoichiometry of dissolved nitrogen and phosphorus in the iron-fertilized region near Kerguelen (Southern Ocean)

2015 ◽  
Vol 12 (2) ◽  
pp. 623-635 ◽  
Author(s):  
S. Blain ◽  
J. Capparos ◽  
A. Guéneuguès ◽  
I. Obernosterer ◽  
L. Oriol
Keyword(s):  
Southern Ocean ◽  
Organic Nitrogen ◽  
Organic Phosphorus ◽  
Polar Front ◽  
Nitrogen And Phosphorus ◽  
Phosphorus Species ◽  
Dissolved Phosphorus ◽  
Dissolved Nitrogen ◽  
Total Dissolved Nitrogen ◽  
Preferential Uptake

Abstract. During KEOPS2 (Kerguelen Ocean and Plateau Compared Study 2), we determined dissolved inorganic and organic nitrogen and phosphorus species in the naturally fertilized region of Kerguelen Island (Southern Ocean). Above 150 m, stations were clearly separated by the polar front (PF), with concentrations of NO3-, NO2- and PO43- overall lower north of the PF than south. Though less pronounced, a similar trend was detectable for dissolved organic nitrogen (DON) and dissolved organic phosphorus (DOP). At all stations offshore and above the plateau, a subsurface maximum of NH4+ was observed between 50 and 150 m. We examined nutrient stoichiometry by calculating the linear combination N* = [NO3-]-16 [PO43-]. The majority of stations and depths revealed N* close to −3 μM; however, for surface waters north of the PF, N* increased up to 6 μM. This suggests a preferential uptake of PO43- versus NO3- by fast-growing diatoms. Using the tracer TNxs = [TDN]-16[TDP] (TDN, total dissolved nitrogen; TDP, total dissolved phosphorus) revealed that the dissolved organic fraction significantly contributed to changes in TNxs. TNxs values were negative for most stations and depths, and relatively constant in the 0–500 m layer. As for N*, the stations north of the PF had higher TNxs in the 0–100 m layer. We discuss this stoichiometric anomaly with respect to possible external sources and sinks of N and P. Additional data collected in February 2013 at two sites revealed the occurrence of a subsurface minimum of N* located just below the pycnocline, which denotes a layer where remineralization of particulate organic matter with low N : P ratio P, possibly associated with preferential remineralization of P versus N, persists throughout the season.

scholarly journals Efficiency of aquatic macrophytes to treat Nile tilapia pond effluents

2006 ◽  
Vol 63 (5) ◽  
pp. 433-438 ◽  
Author(s):  
Gustavo Gonzaga Henry-Silva ◽  
Antonio Fernando Monteiro Camargo
Keyword(s):  
Total Nitrogen ◽  
Total Phosphorus ◽  
Nile Tilapia ◽  
Aquatic Macrophytes ◽  
Fish Farming ◽  
Pistia Stratiotes ◽  
Fish Pond ◽  
Nitrogen And Phosphorus ◽  
Dissolved Phosphorus ◽  
Dissolved Nitrogen

The effluents from fish farming can increase the quantity of suspended solids and promote the enrichment of nitrogen and phosphorus in aquatic ecosystems. In this context, the aim of this work was to evaluate the efficiency of three species of floating aquatic macrophytes (Eichhornia crassipes, Pistia stratiotes and Salvinia molesta) to treat effluents from Nile tilapia culture ponds. The effluent originated from a 1,000-m² pond stocked with 2,000 male Nile tilapia Oreochromis niloticus. The treatment systems consisted of 12 experimental tanks, three tanks for each macrophyte species, and three control tanks (without plants). Water samples were collected from the: (i) fish pond source water, (ii) effluent from fish pond and (iii) effluents from the treatment tanks. The following water variables were evaluated: turbidity, total and dissolved nitrogen, ammoniacal-N, nitrate-N, nitrite-N, total phosphorus and dissolved phosphorus. E. crassipes and P. stratiotes were more efficient in total phosphorus removal (82.0% and 83.3%, respectively) and total nitrogen removal (46.1% and 43.9%, respectively) than the S. molesta (72.1% total phosphorus and 42.7% total nitrogen) and the control (50.3% total phosphorus and 22.8% total nitrogen), indicating that the treated effluents may be reused in the aquaculture activity.

Variability in surface water chemistry and phytoplankton biomass in two tropical, tidally dominated mangrove creeks

1999 ◽  
Vol 50 (5) ◽  
pp. 451 ◽  
Author(s):  
L. A. Trott ◽  
D. M. Alongi
Keyword(s):  
Surface Water ◽  
Phytoplankton Biomass ◽  
Physicochemical Characteristics ◽  
Nutrient Concentrations ◽  
Wet Season ◽  
Inorganic N ◽  
Dissolved Nutrients ◽  
Nitrogen And Phosphorus ◽  
Surface Water Chemistry ◽  
Dissolved Nitrogen

Surface water concentrations of dissolved nutrients and phytoplankton biomass (as chlorophyll a) were examined monthly in relation to physicochemical characteristics and rainfall for 30 months in two tropical, tidally dominated mangrove creeks in north Queensland, Australia. Dissolved nutrient concentrations and phytoplankton biomass peaked during summer with no or little significant change throughout the rest of the year. Dissolved nitrogen and phosphorus concentrations correlated inversely with salinity changes, implying that fresh water and suspended material from the watershed were the main source of dissolved nutrients.The mean dissolved inorganic N : P ratio in each creek (Control Creek 58 : 1, Sandfly Creek 26 : 1) was greater than the Redfield ratio (16 : 1), suggesting excess nitrogen relative to phosphorus. Variability in phytoplankton biomass did not correlate significantly with dissolved nitrogen or phosphorus concentrations, but did relate to rainfall patterns and changes in dissolved oxygen concentrations.These results suggest that pelagic conditions in these mangrove creeks are constant all year round, except during the summer wet season.

scholarly journals Spatiotemporal evolution of ecosystem services in South China Karst and driving mechanism

2021 ◽  
Author(s):  
Shihao ZHANG
Keyword(s):  
Soil Conservation ◽  
Driving Forces ◽  
Driving Mechanism ◽  
Spatiotemporal Evolution ◽  
Nitrogen And Phosphorus ◽  
Rocky Desertification ◽  
Natural Factors ◽  
Increasing Trend ◽  
Main Factors ◽  
Phosphorus Export

To explore the above-mentioned problems, we analyzed the spatiotemporal evolution of ES (WY, SC, NPP, nitrogen and phosphorus export, HQ, CS, and Bio) in SCK, and combined policy (GFG), natural factors (MP, MT, PET, and VC) and human activities (PD, NL, GDP, FL, Forest, Grass, BL and UL) discussed the driving forces of ES changes in different landscapes. The results showed that from 1982 to 2018, WY, nitrogen Export, HQ, CS and Bio in SCK showed a decreasing trend, while SC and NPP showed an increasing trend. WY had a large decrease in all ES, a decrease of 13.23%; while NPP had a large increase, an increase of 19.16%. Comparing different landscape, the study found that SC, NPP, nitrogen and phosphorus export, CS and Bio in non-karst were higher than in karst, while HQ was the opposite. This study showed that natural factors (MP, MT, PET and VC) are the main factors of affecting ES in SCK, and found that the driving factors of ES indicators in different landscapes (karst and non-karst) are not the same. The study emphasized mountain enclosure for afforestation in karst suitable forests and barren hills to restore ES; fast-growing and pioneer species with a large amount of fine roots were planted in wasteland and rocky desertification areas to increase soil conservation services in the early ecosystems; through the policy of migration and employment, the human disturbance to nature can be reduced and habitat quality and biodiversity service can be improved.

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