Diffuse nutrient losses in Denmark

1996 ◽  
Vol 33 (4-5) ◽  
pp. 81-88 ◽  
Author(s):  
B. Kronvang ◽  
P. Græsbøll ◽  
S. E. Larsen ◽  
L. M Svendsen ◽  
H. E. Andersen
Keyword(s):  
Aquatic Environment ◽  
Nutrient Loading ◽  
Nitrogen Loading ◽  
Point Sources ◽  
Phosphorus Loading ◽  
Total N ◽  
Diffuse Sources ◽  
Agricultural Catchments ◽  
Annual Total ◽  
Total P

Since 1989, nutrient loading of the Danish aquatic environment has been monitored in 270 Danish streams draining catchment areas differing in climate, physico-geographic and land usage. Diffuse nutrient loading from non-point sources (mainly agricultural) is now the main cause of eutrophication of the Danish aquatic environment; thus in 1993, diffuse sources accounted for 94% of riverine nitrogen loading and 52% of riverine phosphorus loading. Annual riverine total nitrogen (total-N) loading from diffuse sources during the period 1989-93 was on average 10 times greater in 66 small agricultural catchments (median 23.4 kg N ha−1) than in 9 natural catchments (median 2.2 kg N ha−1). Correspondingly, annual riverine total phosphorus (total-P) loading from diffuse sources was on average 3.5 times greater in the agricultural catchments (0.29 kg P ha−1) than in the natural catchments (0.07 kg P ha−1). The annual total-N and total-P load was found to increase with the proportion of agricultural land in the catchments. In 1993, intensive measurements of phosphorus load in 8 agricultural catchments showed that normal point sampling (fortnightly) underestimates annual total-P loading by a median of 37% as compared to that estimated by frequent sampling. Moreover, estimates of monthly total-P loading are even more biased, especially in late summer and early autumn (−50% to −65%).

Sources and transport of phosphorus in the Vltava river basin (Czech Republic)

1996 ◽  
Vol 33 (4-5) ◽  
pp. 137-144 ◽  
Author(s):  
Josef Hejzlar ◽  
Vojtech Vyhnálek ◽  
Jirí Kopácek ◽  
Jirí Duras
Keyword(s):  
Czech Republic ◽  
Population Density ◽  
Atmospheric Deposition ◽  
River Basin ◽  
Point Sources ◽  
Diffuse Sources ◽  
River Elbe ◽  
Municipal Wastewaters ◽  
Total P

Export and sources of P in the Vltava basin (subbasin of upper Elbe: total area – 28,093 km2; population density – 115 km−2; forests – 35%, farmland – 51%) were evaluated during 1972–1993. Annual export rates of total P from the basin to the river Elbe ranged between 38 and 68 kg km−2 a−1. Reservoirs with hydraulic retention times longer than 15 days were efficient traps for phosphorus retaining 20 to 30% of total P loading into the watercourses. Point sources (municipal wastewaters) were most important throughout the period and their share varied from approximately 60% in wet years to more than 90% in dry years. Export from diffuse sources (dominated by output from farmland) was highly dependent on discharge and fluctuaded between 5 and 40 kg km−2 a−1 in dry and wet years, respectively. Only about 2% of the P input into the basin from the fertilisation of farmland and from the atmospheric deposition was exported to the watercourses.

Nutrient removal from on-site wastewater in horizontal subsurface flow constructed wetlands in Ireland

2011 ◽  
Vol 6 (3) ◽  
Author(s):  
N. O'Luanaigh ◽  
L. W. Gill
Keyword(s):  
Subsurface Flow ◽  
Septic Tank ◽  
Tertiary Treatment ◽  
Total N ◽  
Annual Total ◽  
Isotope Studies ◽  
Horizontal Subsurface Flow ◽  
Domestic Effluent ◽  
15N Stable Isotope ◽  
Total P

Two horizontal subsurface flow wetlands were constructed on separate sites in Ireland - one to provide secondary treatment and the other to provide a tertiary treatment for single house domestic effluent. A comprehensive analysis over three years provided a robust characterisation of the internal dynamics of the systems with respect to N and P removal. The removal of Total N was only 29% and 30% in the secondary and tertiary treatment wetlands respectively and revealed a drop off in performance over time with a higher release of org-N during summer periods. 15N stable isotope studies confirmed that 35% of the ammonium from the septic tank was passing straight through the process without taking part in any biogeochemical processes. However, the study showed that influent N in both wetlands was being biologically assimilated into organic nitrogen (biomass or plants) and then released again as soluble ammonium – so-called nitrogen “spiraling”. Removal of Total P in the wetlands averaged 45% and 28% respectively. The results also showed that if the annual above ground stem matter was completely removed it would only account for 8.4% and 1.3% of the annual total P-load to the respective wetlands. Accordingly the effluent PO4-P concentrations were still found to be >5 mg/l on average.

Mapping areas at risk of diffuse phosphorus losses to water: a pilot study of Lake Haderslev Dam, Denmark

2008 ◽  
Vol 58 (11) ◽  
pp. 2173-2178 ◽  
Author(s):  
Hans Estrup Andersen ◽  
Goswin Heckrath ◽  
Hans Thodsen
Keyword(s):  
At Risk ◽  
Pilot Study ◽  
Point Sources ◽  
Mitigation Measures ◽  
Phosphorus Loading ◽  
Ecological Quality ◽  
Risk Areas ◽  
Lake Catchment ◽  
Phosphorus Losses ◽  
Total P

Haderslev Dam is a 272 ha lake in southern Denmark with a high recreational value. For decades the lake has been severely eutrophicated due to excessive phosphorus loading. Major point sources were cut off in the early 1990s and an upstream wetland was recreated. However, the ecological quality remains unsatisfactory. In this study we estimate the importance of agriculture on diffuse phosphorus (P) input to the lake by modelling combined with independent estimates for contributions from scattered dwellings not connected to a sewer and from background losses. We apply a newly developed Danish P index to the lake catchment for mapping of risk areas for diffuse phosphorus losses. For risk areas we suggest mitigation measures and estimate the effect of the mitigation measures on the total P loading of the lake as well as the associated costs.

Is the destabilisation of lake Peipsi ecosystem caused by increased phosphorus loading or decreased nitrogen loading?

2005 ◽  
Vol 51 (3-4) ◽  
pp. 267-274 ◽  
Author(s):  
T. Nõges ◽  
R. Laugaste ◽  
E. Loigu ◽  
I. Nedogarko ◽  
B. Skakalski ◽  
...  
Keyword(s):  
Catchment Area ◽  
Nutrient Loading ◽  
Nitrogen Loading ◽  
Phosphorus Loading ◽  
Lake Area ◽  
Fish Kills ◽  
Lake Peipsi ◽  
Temporary Reduction ◽  
Loading Ratio

Lake Peipsi (3,555 km2, mean depth 7.1 m) located on the border of Estonia and Russia is the largest transboundary lake in Europe. L. Peipsi consists of three parts. The shared largest northern part L. Peipsi s.s. (2,611 km2, 8.3 m) and the southern L. Pihkva (708 km2, 3.8 m) which belongs mainly to Russia are connected by the river-shaped L. Lämmijärv (236 km2, 2.5 m). The catchment area (44,245 km2 without lake area) is shared between Estonia (33.3%), Russia (58.6%) and Latvia (8%). Intensive eutrophication of L. Peipsi started in the 1970s. The biomass of N2-fixing cyanobacteria was low at heavy nutrient loading in the1980s. After the collapse of soviet-type agriculture in the early 1990s, the loading of nitrogen sharply decreased. A certain improvement of L. Peipsi s.s. was noticed at the beginning of the 1990s together with the temporary reduction of phosphorus loading from Estonian catchment while in recent years a destabilisation of the ecosystem has been observed. This deterioration has been expressed mainly as intensive blue-green blooms and fish-kills in summer. Reappearance of blooms has been explained by the decrease in N/P loading ratio due to reduced N discharge while in some periods increased phosphorus loading could have supported this trend.

scholarly journals Treatment of Agricultural Drainage Water by Surface-Flow Wetlands Paired with Woodchip Bioreactors

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1891
Author(s):  
Lorenzo Pugliese ◽  
Henrik Skovgaard ◽  
Lipe R. D. Mendes ◽  
Bo V. Iversen
Keyword(s):  
Drainage Water ◽  
Surface Flow ◽  
Design Concept ◽  
Ecological Disturbance ◽  
Total N ◽  
Agricultural Catchments ◽  
Management Plans ◽  
Nutrient Mass Balance ◽  
Total P ◽  
P Removal

Nutrient losses from agricultural fields have long been a matter of concern worldwide due to the ecological disturbance this can cause to surface waters downstream. In this paper a new design concept, which pairs a surface-flow constructed wetland (SFW) with a woodchip bioreactor (WB), was tested in relation to its capacity to reduce both nitrogen (N) and phosphorus (P) loads from agricultural tile drainage water. A nutrient mass balance and a comparative analysis were carried out together with statistical regressions in order to evaluate the performance of four SFW+WBs under different catchment conditions. We found marked variations between the systems in regard to hydraulic loading rate (0.0 to 5.0 m/day) and hydraulic retention time (1 to 87 days). The paired system worked as nutrient sinks throughout the study period. Total N and total P removal efficiencies varied from 8% to 51% and from 0% to 80%, respectively. The results support the use of the new design concept for nutrient removal from tile-drained agricultural catchments in Denmark as part of national management plans, with the added advantage that smaller areas are needed for construction (0.1% to 0.2% of the catchment area) in comparison to standalone and currently used SCWs (~1%).

Nutrient status of Lake Liddel, New South Wales: mass loadings of nitrogen and phosphurus, industrial modification, and trophic state

1992 ◽  
Vol 43 (2) ◽  
pp. 443 ◽  
Author(s):  
RN Royle ◽  
RJ King
Keyword(s):  
Point Source ◽  
New South ◽  
Nutrient Status ◽  
Nutrient Concentrations ◽  
Nitrogen And Phosphorus ◽  
Total N ◽  
South Wales ◽  
Annual Total ◽  
The Mean ◽  
Total P

The concentrations of nitratehitrite-N, Kjeldahl-N and total P in point-source additions to and losses from Lake Liddell (32° 22'S,150° 1'E) were measured fortnightly from September 1987 to September 1988. These data were used in conjunction with flow-rate data to construct a nitrogen and phosphorus budget from Lake Liddell. The annual net point-source loadings of nitrogen and phosphorus were 23 400 and 5700 kg, respectively. There was little relationship between changes in lake nutrient concentrations and fortnightly mass loadings. The mean molar N: P ratio for point source mass additions was 13: 1, whereas that within the lake was 33: 1. These features indicate that within-lake processes were the dominant processes in determining lake nutrient concentrations. Retention in the sediments of a greater proportion of the total P pool than of the total-N pool appeared to be one of these processes. The use of Lake Liddell water in power-station operations resulted in substantial increases in nitrate/ nitrite-N and total-P concentrations in waters returned to the lake. The use of Dillon's model to predict mean annual total-P concentrations from mass loadings indicates that Lake Liddell is on the border between mesotrophic and eutrophic states.

scholarly journals Testing the INCA model in a small agricultural catchment in southern Finland

2004 ◽  
Vol 8 (4) ◽  
pp. 717-728 ◽  
Author(s):  
K. Granlund ◽  
K. Rankinen ◽  
A. Lepistö
Keyword(s):  
Land Use ◽  
Stream Water ◽  
Inorganic Nitrogen ◽  
Hydrological Regime ◽  
Nitrogen Loading ◽  
Integrated Modelling ◽  
Total N ◽  
Climate Conditions ◽  
Heterogeneous Soil ◽  
Annual Total

Abstract. Nutrient leaching from agricultural production is still recognised as a major environmental problem in Finland. To estimate agricultural nitrogen loading under changing land-use and climate conditions, the Integrated Nitrogen Model for Catchments (INCA) was applied in Savijoki, a small (15.4 km2) agricultural catchment, which represents the intensively cultivated areas in south-western Finland. Hydrological calibration and testing of the INCA model was first carried out in Savijoki during 1981–2000. In spite of heterogeneous soil and land-use conditions, INCA was able to reproduce the overall hydrological regime in the stream. The model was calibrated further in respect of nitrogen processes during 1995–2000. The model was able, reasonably well, to simulate the overall annual dynamics of the inorganic N concentrations in the stream water and the annual N export from the catchment. The average simulated NO3-N export was 550 kg N km–2 yr–1 and the observed one (constituting more than half of the annual total N export) was 592 kg N km–2 yr–1. For NH4-N, the simulated export was somewhat higher than that measured but NH4-N was only 4% of the total N export. In spite of some underestimation of flow and N concentration during extreme hydrological conditions, the INCA model proved to be a useful tool for analysing flow pattern and inorganic nitrogen leaching in a small agricultural catchment, characterised by a rapid response to rainfall. Keywords: nitrogen, integrated modelling, hydrology, catchment, agriculture

Non-point-source nutrient losses to the aquatic environment in Denmark: impact of agriculture

1995 ◽  
Vol 46 (1) ◽  
pp. 167 ◽  
Author(s):  
B Kronvang ◽  
R Grant ◽  
SE Larsen ◽  
LM Svendsen ◽  
P Kristensen
Keyword(s):  
Surface Water ◽  
Point Source ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Aquatic Environment ◽  
Nutrient Loading ◽  
Agricultural Land ◽  
Agricultural Catchments ◽  
Surface Water And Groundwater ◽  
The Impact

As part of a coordinated programme for nationwide monitoring of the Danish aquatic environment, initiated in 1988, nutrient fluxes are measured in 270 rivers, and nutrient cycling is studied in six agricultural catchments. This enables assessment of the degree of non-point-source nutrient loading of Danish surface water and groundwater as well as of the impact of agriculture practised under different climatic and physiographic conditions and with different farming practices. Comparison of annual median losses of total nitrogen and total phosphorus in agricultural catchments and undisturbed catchments revealed an average loss ratio of 14:l for total nitrogen (23.4 and 1.7 kg N ha-1, respectively) and 4:1 for total phosphorus (0.29 and 0.070 kg P ha-1, respectively). Assessment of nitrogen cycling in six small agricultural catchments with either sandy soil or loamy soil revealed marked differences in annual net input to the soil (142 v. 77 kg N ha-1), annual leaching from the root zone (154 v. 78 kg N ha-1), and annual riverine loss of nitrogen (13 v. 25 kg N ha-1). The differences in the rates of leaching and riverine loss in the two soil types reflect the different potential for surface-water and groundwater pollution with nitrogen and also the fact that the denitrification potential is higher in both the soil and the riparian areas of sandy ecosystems. Modelling of data from 77 small representative river basins revealed significant empirical relationships (P <0.001) between annual loss of both nitrogen and phosphorus and various predictor variables (e.g. runoff, proportion of agricultural land, soil type). Runoff and proportion of agricultural land explained, respectively, 41% and 26% of the variance in the nitrogen-model and 45% and 8%, of the variance in the phosphorus model. Such loading models are valuable tools for systems analysis and management at the catchment level, such as when assessing measures implemented to reduce non-point-source nutrient pollution.

LAND USE TYPES AND SOIL CHARACTERISTICTS: A CASE STUDY IN HUONG VINH COMMUNE, HUONG TRA TOWN, THUA THIEN HUE PROVINCE

2017 ◽  
Vol 126 (4B) ◽  
Author(s):  
Trần Thanh Đức
Keyword(s):  
Land Use ◽  
Sweet Potato ◽  
Soil Analysis ◽  
Soil Characteristics ◽  
Low Ph ◽  
Clay Loam ◽  
Total N ◽  
Land Use Types ◽  
Total P

This research carried out in Huong Vinh commune, Huong Tra town, Thua Thien Hue province aimed to identify types of land use and soil characteristics. Results showed that five crops are found in Huong Vinh commune including rice, peanut, sweet potato, cassava and vegetable. There are two major soil orders with four soil suborders classified by FAO in Huong Vinh commune including Fluvisols (Dystric Fluvisols<em>, </em>Gleyic Fluvisols and Cambic Fluvisols) and Arenosols (Haplic Arenosols). The results from soil analysis showed that three soil suborders including Dystric Fluvisols<em>, </em>Gleyic Fluvisols and Cambic Fluvisols belonging to Fluvisols were clay loam in texture, low pH, low in OC, total N, total P<sub>2</sub>O<sub>5</sub> and total K<sub>2</sub>O. Meanwhile, the Haplic Arenosols was loamy sand in texture, poor capacity to hold OC, total N, total P<sub>2</sub>O<sub>5</sub> and total K<sub>2</sub>O

Nitrogen and phosphorus in the Vistula River, Poland -- changes from source to mouth

1994 ◽  
Vol 30 (5) ◽  
pp. 177-186 ◽  
Author(s):  
Karin Sundblad ◽  
Andrzej Tonderski ◽  
Jacek Rulewski
Keyword(s):  
Central Region ◽  
Northern Region ◽  
Point Sources ◽  
Nutrient Loss ◽  
Phosphorus Concentration ◽  
Nitrogen And Phosphorus ◽  
Concentration Data ◽  
Diffuse Sources ◽  
Vistula River ◽  
South Central

Nitrogen and phosphorus concentration data representing samples collected once a month for nine months at 13 locations along the Vistula River are considered in a preliminary discussion of the sources of the nutrients transported to the Baltic Sea. Concentrations in relation to flow data indicated substantial differences between subbasins. Based on those differences, on the area-specific nutrient loss for a six-month period and on the wastewater discharge in each subbasin, four regions could be recognized in the river basin: i) the southern region with a large impact of point sources, ii) the south central region, where diffuse sources seemed to be of major importance, iii) the north central region with a combined effect of point and diffuse sources, and retention in two reservoirs, iv) the northern region where point sources seemed to be the dominating source, at least for phosphorus. Our results illustrate the importance of differences in phosphorus retention between the basins. Long-term retention along the course of the river, particularly in the two reservoirs, must be estimated to allow proper source apportionment in the Vistula basin. Concentration decreases in the Wloclawek Reservoir varied between 44 and 68% for P, and 11 to 37% for N, in the months with significant retention. In some months, however, concentrations increased, indicating a release of nutrients.

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