Agricultural practices and diffuse nitrogen pollution in Denmark: empirical leaching and catchment models

1999 ◽  
Vol 39 (12) ◽  
pp. 257-264 ◽  
Author(s):  
Hans E. Andersen ◽  
Brian Kronvang ◽  
Søren E. Larsen
Keyword(s):  
Agricultural Land ◽  
Root Zone ◽  
Agricultural Practices ◽  
Animal Manure ◽  
Annual Runoff ◽  
N Leaching ◽  
N Loss ◽  
Total N ◽  
Model Calculations ◽  
N Removal

An empirical leaching model was applied to data on agricultural practices at the field level within 6 small Danish agricultural catchments in order to document any changes in nitrogen (N) leaching from the root zone during the period 1989-96. The model calculations performed at normal climate revealed an average reduction in N-leaching that amounted to 30% in the loamy catchments and 9% in the sandy catchments. The reductions in N leaching could be ascribed to several improvements in agricultural practices during the study period: (i) regulations on livestock density; (ii) regulations on the utilisation of animal manure; (iii) regulations concerning application practices for manure. The average annual total N-loss from agricultural areas to surface water constituted only 54% of the annual average N leached from the root zone in the three loamy catchments and 17% in the three sandy catchments. Thus, subsurface N-removal processes are capable of removing large amounts of N leached from agricultural land. An empirical model for the annual diffuse N-loss to streams from small catchments is presented. The model predicts annual N-loss as a function of the average annual use of mineral fertiliser and manure in the catchment and the total annual runoff from the unsaturated zone.

scholarly journals Long term trends in fertility of soils under continuous cultivation and cereal cropping in southern Queensland .V. Rate of loss of total nitrogen from the soil profile and changes in carbon : nitrogen ratios

Soil Research ◽  
1986 ◽  
Vol 24 (4) ◽  
pp. 493 ◽  
Author(s):  
RC Dalal ◽  
RJ Mayer
Keyword(s):  
Root Zone ◽  
Continuous Cultivation ◽  
N Loss ◽  
Total N ◽  
Cultivation Period ◽  
N Removal ◽  
Long Term Trends ◽  
Red Earth ◽  
Kinetics Of

The kinetics of total N loss from the top (0-0.1 m) and the subsoil (up to 1.2 m depth) of six southern Queensland soils after different periods (0-70 years) of cultivation and cereal cropping, were studied. The equation: Nt = Ne + (No - N,)exp(- kt), where No, Ne and N, are total N concentrations initially, at equilibrium and at time t, respectively, and k is the rate of loss of total N from soil, described total N loss from only three soils. For the 0-0.1 m depth, the kw values (based on weight of total Nholume of soil) were 0.061, 0.115 and 0.275 year-1, respectively for Waco (black earth; initially grassland), Langlands-Logie (grey, brown and red clays; brigalow) and Cecilvale soil (grey, brown and red clays; poplar box). The kw values decreased to less than half at 0-0.6 m depths of those at 0-0.1 m depth. In the other three soils, Billa Billa (grey, brown and red clays; belah), Thallon (grey, brown and red clays; coolibah) and Riverview (red earth; silver-leaved ironbark), total N declined linearly over the 20-25 years of cultivation period studied. Average annual rates of N loss from the profiles of the six soils, respectively, were 31.3, 67.1, 34.5, 50.8, 35.8 and 32.0 kg N ha-1 year-1 , from Waco, Langlands-Logie, Cecilvale, Billa Billa, Thallon and Riverview soils. Except for Langlands-Logie, these losses could be accounted for by crop N removal. In the Langlands-Logie soil, besides N removal by crop (51 kg N ha-1 year-1, 1982-1984 period), leaching of N below the root-zone appeared to be the likely factor for N loss. C:N ratios generally increased with depth in the five clay soils but decreased with depth in the red earth (Riverview). Cultivation had no significant effect on the C:N ratios of Cecilvale, Thallon and Riverview soils, but it caused a decrease in Langlands-Logie soil (up to 0.6 m depth) and an increase in Waco soil (up to 1.2 m depth). It was inferred, therefore, that in the latter, remaining soil N was likely to mineralise more slowly with increasing period of cultivation, resulting in a fertility loss which may be greater than that shown by the decrease in total N.

scholarly journals Cropland Soil Salinization and Associated Hydrology: Trends, Processes and Examples

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 1030 ◽  
Author(s):  
Nachshon Uri
Keyword(s):  
Agricultural Land ◽  
Root Zone ◽  
Agricultural Practices ◽  
Soil Salinization ◽  
World Population ◽  
Arid Environments ◽  
Geological Material ◽  
Degradation Processes ◽  
Sources Of Solutes ◽  
Global Food

While global food demand and world population are rapidly growing, land potential for cropping is steadily declining due to various soil degradation processes, a major one of them being soil salinization. Currently, approximately 20% of total cropland and 33% of irrigated agricultural land are salinized as a result of poor agricultural practices and it is expected that by 2050, half of the croplands worldwide will become salinized. Thus, there is a real need to better understand soil salinization processes and to develop agricultural practices that will enable production of the needed amount of food to feed humanity, while minimizing soil salinization and other degradation processes. The major sources of solutes in agricultural environments are: (i) the soil itself, and the parent geological material; (ii) shallow and salt rich groundwater; and (iii) salt rich irrigation water. The salinization of soil is a combination of transport of solutes towards the root zone to replenish evaporation and transpiration and limited washing of the soil by rain or irrigation. Therefore, most salinized soils are present in arid and semi-arid environments where precipitation is low and evaporation is high. In this manuscript, examples of soil salinization processes from croplands around the world will be presented and discussed to bring attention to this important topic, to present the latest scientific insights and to highlight the gaps that should be filled, from both scientific and practical perspectives.

Implementation of best management practices in agriculture: modelling and monitoring of impacts on nitrogen leaching

2002 ◽  
Vol 45 (9) ◽  
pp. 43-50 ◽  
Author(s):  
A. Joelsson ◽  
K. Kyllmar
Keyword(s):  
Best Management Practices ◽  
Management Practices ◽  
Time Perspective ◽  
Agricultural Land ◽  
Root Zone ◽  
Agricultural Practices ◽  
Nitrogen Leaching ◽  
Best Management ◽  
Indexing Technique ◽  
The Impact

In Kattegat and the coastal water of the Baltic Sea, high nitrogen input from agricultural land is considered to be the main reason for eutrophication. International agreements and governmental programs have set a target to reduce the anthropogenic nitrogen load by 50 percent. Improved nitrogen removal in treatment plants and efforts in agriculture have so far not decreased nitrogen transport to a sufficient extent. In this project the impact of agricultural practices on nitrogen leaching was investigated in two small agricultural catchments in Southwest Sweden. The root-zone leaching was estimated by an indexing technique. Simultaneously the transports in the stream outlets were monitored. During 1995 and 1999 the agricultural practices in the catchments were surveyed. Field data from the first survey indicated that fertilisation did not always match crop requirements, the area of undersown catch crop can be increased and autumn cultivation can be reduced. The second survey was preceded by an advisory campaign where each farmer was visited and presented with an environmental plan including fertilisation, cultivation, and crop rotation for the farm. The plan summarised the best management practices that could be realised under actual conditions. Results from the second survey showed that some changes in the agricultural practices were carried out after the advisory campaign. The nitrogen leaching from the root-zone was then estimated by the indexing technique, both for the time before and after the advisory program. The results showed that the estimated nitrogen leaching, as a mean value for 330 fields, decreased from 53 to 50 kgN ha−1, due to adjustments of the agricultural practices. Monitoring of stream transports showed values of the same magnitude after correction for retention and other sources. In this short time perspective, decreases in transport due to changes in agricultural practices could not be separated from influence of weather conditions. In comparison to results from the Swedish monitoring programme for agriculture, the measured transports were normal for the region, where annual variation in precipitation and runoff is large. Theoretically, nitrogen leaching could be reduced by one third without any major economic constraints for the farmers. In general, the farmers were positive to advice and willing to try new farming techniques even if some measurements were not fully implemented during the investigation period.

scholarly journals Variation of runoff and nitrogen leaching in a small agricultural catchment in southern Finland

2004 ◽  
Vol 35 (4-5) ◽  
pp. 335-345 ◽  
Author(s):  
Kirsti Granlund
Keyword(s):  
Relative Proportion ◽  
Agricultural Practices ◽  
Weather Conditions ◽  
N Deposition ◽  
Annual Runoff ◽  
N Losses ◽  
Total N ◽  
Relative Contribution ◽  
Environmental Programme

Long term monitoring data from 1981–2000 was used to study nitrogen (N) losses from a small (15.4 km2) agricultural catchment in southern Finland. The annual loads of total N, NO3-N and NH4-N varied considerably during the study period. The mean total N load was 820 kg km−2 yr−1. More than half of the annual N load was in the form of NO3-N, while the relative contribution of NH4-N was low, which is common in Finnish agricultural fine-textured soils. The measured annual N loads were highly dependent on runoff. The highest annual N load (1310 kg km−2) was observed in 1984, in accordance with the highest annual runoff (616 mm). Due to mild weather conditions during the winters since 1989, the relative proportion of winter runoff was higher than earlier. So far, no decrease could be seen in annual N loads, even though most of the farmers are participating in the Finnish Agri-Environmental Programme established in 1995. However, the amount of NH4-N load seems to have remained very low (less than 50 kg km−2 yr−1) in Savijoki since 1995, which may reflect changes in agricultural practices and a decrease in N deposition.

Soil N process inhibitors alter nitrogen leaching dynamics in a pumice soil

Soil Research ◽  
2008 ◽  
Vol 46 (4) ◽  
pp. 323 ◽  
Author(s):  
John C. Menneer ◽  
Stewart Ledgard ◽  
Mike Sprosen
Keyword(s):  
Soil Conditions ◽  
N Leaching ◽  
Nitrification Inhibitors ◽  
N Loss ◽  
Macropore Flow ◽  
Total N ◽  
Lysimeter Experiment ◽  
Ammonium N ◽  
Cow Urine ◽  
On Farm

A field lysimeter experiment, using a free-draining pumice soil, was carried out to investigate the effect of different soil nitrogen (N) process inhibitors on the fate of 15N-labelled cow urine. The treatments were a urease inhibitor (Agrotain; N-(n-butyl) thiophosphoric triamide), 2 nitrification inhibitors (dicyandiamide, DCD; 4-methylpyrazole, 4MP), a combination (DCD+Agrotain), a urine control, and a nil urine. The inhibitors were mixed with cow urine, which was then applied in a single application (equivalent to 775 kg N/ha) to lysimeters in autumn and monitored over the following 196 days. DCD and 4MP similarly reduced nitrate leaching by 59%, from 114 to 47 kg N/ha compared with the urine control. Of the DCD applied, 58% of it (8.7 kg/ha) was recovered in leachate, and represented an N loss of 5.8 kg/ha. The presence of Agrotain reduced ammonia (NH3-N) emissions by 64% (equivalent to 70 kg N/ha) over the short term (first 20 days), but led to large leaching losses of urea-N (25 kg N/ha) over the medium term (76 days). The Agrotain-DCD combination resulted in even larger losses of urea-N (45 kg N/ha). The major N component measured in leachate (below 450 mm) was ammonium-N, which constituted about 60% of the average total N (205 kg N/ha) leached. Ammonium-N leaching was rapid and almost entirely driven by macropore flow processes. Further research is required in deeper soil profiles, and in relation to climatic risk of high early rainfall on fresh urine patches, to determine the importance of macropore processes on N loss under typical on-farm soil conditions.

scholarly journals SEASONAL DYNAMICS OF NITROGEN IN CULTIVATED SOIL AT GIAO THUY DISTRICT, NAM DINH PROVINCE

2018 ◽  
Vol 56 (2C) ◽  
pp. 186-192
Author(s):  
Ly Thi Thu Ha
Keyword(s):  
Nitrogen Mineralization ◽  
Seasonal Dynamics ◽  
Rainy Season ◽  
Root Zone ◽  
Saline Soil ◽  
Paddy Fields ◽  
N Leaching ◽  
Total N ◽  
Leaching Losses ◽  
Vegetable Rotation

This paper focuses on evaluating the nitrogen mineralization and NH4+ and NO3- leaching from the root zone in cultivated soils of Giao Thuy district, Nam Dinh province using Synthetic accumulation (SIA) method. Main findings reveal that total N content in vegetable fields and rice-vegetable-rotational fields ranges from 17.68 – 113.68 kgN ha-1, and from 14.64 – 132.59 kgN ha-1, respectively. Total N is also significantly different between saline paddy-fields and fresh-water fields, varies between 16.33 – 82.12 kgN ha-1 and from 23.89 – 74.04 kgN ha-1, respectively. NO3- accounts for a larger proportion in vegetable fields and accumulated higher during the dry season; NH4+ predominates in paddy fields and accumulated mainly in rainy season. The N leaching losses decreased in the following order: vegetable, rice-vegetable rotation, non-saline and saline soil. 

Treatment of Wastewater in the Rhizosphere of Wetland Plants – The Root-Zone Method

1987 ◽  
Vol 19 (1-2) ◽  
pp. 107-118 ◽  
Author(s):  
Hans Brix
Keyword(s):  
Wastewater Treatment ◽  
Root Zone ◽  
Treatment Plant ◽  
Wetland Plants ◽  
Treated Wastewater ◽  
Treatment Standards ◽  
Nitrogen And Phosphorus ◽  
Zone Method ◽  
Total N ◽  
N Removal

The present paper describes the theoretical basis of wastewater treatment in the rhizosphere of wetland plants, the so-called “root-zone method”, along with the first working experiences from eight treatment plants in Denmark. Mechanically treated wastewater is led horizontally through the rhizosphere of wetland plants. During the passage of the wastewater through the rhizosphere, the wastewater is cleaned by microbiological degradation and by physical/chemical processes. The wetland plants supply oxygen to the heterotrophic microorganisms in the rhizosphere and stabilize the hydraulic conductivity of the soil. Nitrogen is removed by denitrification and phosphorus and heavy metals are bound in the soil. The first working experiences from Denmark show, that as far as BOD is concerned root-zone treatment plants are very nearly up to conventional secondary treatment standards already from the first growing season (removal efficiency: 51-95%). For the nutrients nitrogen and phosphorus the results vary (total-N removal: 10-88%; total-P removal: 11-94%). The removal efficiencies depended mainly on the composition of the soils and the degree of surface runoff in each treatment plant. It is concluded that root-zone treatment plants seem to be a viable alternative to conventional wastewater treatment technology, especially suitable for single households and small to medium sized communities. There is, however, still very little information on the removal processes for nitrogen (denitrification), on the effect of soil type and on the required surface area to load ratio,

scholarly journals Modelling the risk of nitrate leaching from two soils amended with five different biosolids

2005 ◽  
Vol 29 (4) ◽  
pp. 619-626 ◽  
Author(s):  
Rodrigo Studart Corrêa ◽  
Robert Edwin White ◽  
Anthony James Weatherley
Keyword(s):  
Sewage Sludge ◽  
Plant Nutrition ◽  
Root Zone ◽  
Field Capacity ◽  
Land Application ◽  
N Leaching ◽  
N Loss ◽  
Application Rates ◽  
Agricultural Use ◽  
Composted Sludge

High N concentrations in biosolids are one of the strongest reasons for their agricultural use. However, it is essential to understand the fate of N in soils treated with biosolids for both plant nutrition and managing the environmental risk of NO3--N leaching. This work aimed at evaluating the risk of NO3--N leaching from a Spodosol and an Oxisol, each one treated with 0.5-8.0 dry Mg ha-1 of fresh tertiary sewage sludge, composted biosolids, limed biosolids, heat-dried biosolids and solar-irradiated biosolids. Results indicated that under similar application rates NO3--N accumulated up to three times more in the 20 cm topsoil of the Oxisol than the Spodosol. However, a higher water content held at field capacity in the Oxisol compensated for the greater nitrate concentrations. A 20 % NO3--N loss from the root zone in the amended Oxisol could be expected. Depending on the biosolids type, 42 to 76 % of the NO3--N accumulated in the Spodosol could be expected to leach down from the amended 20 cm topsoil. NO3--N expected to leach from the Spodosol ranged from 0.8 (composted sludge) to 3.5 times (limed sludge) the amounts leaching from the Oxisol treated alike. Nevertheless, the risk of NO3--N groundwater contamination as a result of a single biosolids land application at 0.5-8.0 dry Mg ha-1 could be considered low.

Solute dynamics and the Ontario nitrogen index: II. Nitrate leaching

2016 ◽  
Vol 96 (2) ◽  
pp. 122-135 ◽  
Author(s):  
C.F. Drury ◽  
W.D. Reynolds ◽  
G.W. Parkin ◽  
J.D. Lauzon ◽  
J.K. Saso ◽  
...  
Keyword(s):  
Root Zone ◽  
Agricultural Soils ◽  
Sandy Loam ◽  
N Leaching ◽  
N Recovery ◽  
N Loss ◽  
Solute Dynamics ◽  
N Management ◽  
N Rates ◽  
Leaching Risk

Nitrogen (N) leaching from soil into surface and ground waters is a concern in humid areas of Canada. As a result, N management protocols, including the Ontario N Index, are widely used to identify N leaching risk, although field assessment remains limited. Nitrogen fertilizer and chloride (Cl) tracer were fall-applied to five agricultural soils in Ontario with different textures and hydrologic soil groups (HSG) to assess the Ontario N Index and characterize inorganic N movement over 1 yr. The treatments included three N rates (0, 100, and 200 kg N ha−1) plus Cl tracer and 200 kg N ha−1 rate without Cl. After spring thaw, N loss from the crop root zone (top 60 cm) ranged from 68% for Brookston clay loam to 99% for Harrow sandy loam. A strong linear relationship between apparent N recovery and apparent Cl recovery indicated that N loss from the root zone occurred primarily by downward leaching. Leaching was controlled by the minimum measured saturated hydraulic conductivity (Ksat), and good estimates of N leaching were obtained using a quasi-theoretical relationship between N loss and Ksat. We concluded that Ontario N Index estimates of N leaching risk might be improved by including site-specific measurements of Ksat.

Impact of Nitrogen Management Practices on Total Nitrogen in the Fruits of High Productive Hamlin Orange Trees

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 498e-498
Author(s):  
S. Paramasivam ◽  
A.K. Alva
Keyword(s):  
Crop Production ◽  
Management Practices ◽  
Fine Sand ◽  
Fruit Production ◽  
Perennial Crop ◽  
Total N ◽  
N Removal ◽  
Leaf N Concentration ◽  
N Rates ◽  
Orange Trees

For perennial crop production conditions, major portion of nutrient removal from the soil-tree system is that in harvested fruits. Nitrogen in the fruits was calculated for 22-year-old `Hamlin' orange (Citrus sinensis) trees on Cleopatra mandarin (Citrus reticulata) rootstock, grown in a Tavares fine sand (hyperthermic, uncoated, Typic Quartzipsamments) that received various N rates (112, 168, 224, and 280 kg N/ha per year) as either i) broadcast of dry granular form (DGF; four applications/year), or ii) fertigation (FRT; 15 applications/year). Total N in the fruits (mean across 4 years) varied from 82 to 110 and 89 to 111 kg N/ha per year for the DGF and FRT sources, respectively. Proportion of N in the fruits in relation to N applied decreased from 74% to 39% for the DGF and from 80% to 40% for the FRT treatments. High percentage of N removal in the fruits in relation to total N applied at low N rates indicate that trees may be depleting the tree reserve for maintaining fruit production. This was evident, to some extent, by the low leaf N concentration at the low N treatments. Furthermore, canopy density was also lower in the low N trees compared to those that received higher N rates.

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