The spatial heterogeneity of agricultural soil-landscapes is mostly not taken into account in environmental policies. Most environmental goals have been defined at national level or farm level but not at the landscape level. The potential for setting up a regional environmental monitoring network that supports self governance was explored. The research was performed in the Northern Friesian Woodland

Knotters, M.

Kros, J.

Sonneveld, M.P.W.

Vos, J.A., de

Vries, W., de

English

Wageningen Yield 

© 2010 19th World Congress of Soil Science, Soil Solutions for a Changing World 
1 – 6 August 2010, Brisbane, Australia.  Published on DVD. 
99 
Environmental monitoring in heterogeneous soil-landscapes; A Dutch case study 
 
M. P. W. Sonneveld
A
, J. A. de Vos
B
, W. De Vries
B
, M. Knotters
B
 and J. Kros
B
 
 
ALand Dynamics Group, Wageningen University, Wageningen, The Netherlands, Email Marthijn.sonneveld@wur.nl 
BAlterra, Wageningen University and Research centre, The Netherlands. 
 
 
Abstract 
There is scope for developing environmental monitoring programs at the landscape level to address the 
feedback mechanisms at this scale. For a Dutch landscape dominated by dairy farming we have i) derived the 
environmental goals for atmospheric quality and water quality and ii) assessed the current environmental 
quality using a combination of measurements and model calculations. The analysis was limited to nitrogen 
(N) and phosphorus (P) compounds which are the chemical elements most closely related to agriculture. 
Environmental goals at the landscape scale were derived for five individual indicators: NH3 emission, critical 
atmospheric N deposition, N in surface water, P in surface water and NO3 in the upper groundwater. 
In the study area, the NH3 emission goal for 2010, is not exceeded in 2004. However, simulation results 
suggest that critical N deposition rates on nature areas are exceeded on more than half of the area (53%), 
mainly as a result from non-agricultural sources and sources outside the NFW region. For the region as a 
whole, annual NO3 concentrations in the upper groundwater almost never exceed the EU threshold of 50 
mg/L. The national N standards for surface water regarding N and P are only slightly exceeded  
 
Key Words 
Environmental quality, dairy farming, nitrogen, phosphorus. 
 
Introduction 
The spatial heterogeneity of agricultural soil-landscapes is mostly not taken into account in environmental 
policies. Most environmental goals have been defined at national level or farm level but not at the landscape 
level. Consequently, most environmental monitoring programs are operational at national level or farm level. 
There is scope however for developing monitoring programs from a regional landscape and watershed 
perspective because of the extent of environmental contaminants, their potential for transport through 
complex hydrological and atmospheric pathways and the impacts beyond local conditions (Bruns and 
Wiersma 2004). In this study, we used the DPSIR framework as a tool to distinguish between various 
environmental indicators. For a Dutch landscape dominated by dairy farming we have i) derived for 
environmental goals for atmospheric quality and water quality and ii) assessed the current environmental 
quality using a combination of measurements and model calculations (STONE and Initiator). The potential 
for setting up a regional environmental monitoring network that supports self governance was explored. The 
analysis was limited to nitrogen (N) and phosphorus (P) compounds which are the chemical elements most 
closely related to agriculture. 
 
The research was performed in the Northern Friesian Woodlands (NFW), which is located in the province of 
Friesland in the North of The Netherlands (Figure 1). A large part of the 600 km
2
 area as been appointed as a 
Dutch National Landscape because of the small scale parcelling structure, a high concentration of hedge-
rows bordering the individual fields and the occurrence of many pingo-remnants from the Weichsel glacial 
period. The area dominantly consists of sandy soils (Gleyic Podzols) at elevations of 1 to 5 m above mean 
sea level. Clay soil and peat soil are found in the north and the west of the study area in lower landscape 
positions.  
 
Agriculture dominates the landscape using 76% of the total area. Mostly this is grassland (69%) used for 
dairy farming. Surface water occupies 5% of the area and the remainder is used for built-up (13%) and nature 
(6%). In 2004, 92% (1169) of the total number of farms were animal farms, mostly dairy farms. 
Environmental goals at the landscape scale were derived for five individual indicators: NH3 emission, 
critical atmospheric N deposition, N in surface water, P in surface water and NO3- in the upper groundwater.   
Based on areal fractions, a provincial goal of 12 kton NH3/yr can be calculated for the province of Friesland 
using the national EU derived emission ceiling as input. With the model Initiator (De Vries et al. 2003), the 
NH3 emission goal for the NFW region was calculated at 2.6 kton NH3/yr for 2010. To derive the regional 
goals for critical N deposition, the inventories of Bal et al. (2006) were used which indicate critical N  
© 2010 19th World Congress of Soil Science, Soil Solutions for a Changing World 
1 – 6 August 2010, Brisbane, Australia.  Published on DVD. 
100 
 
Figure 1. Distribution of soils in the study area, in the North of the Netherlands. 
 
deposition targets for specific types of vegetation. The provincial map for nature areas was then used to map 
the critical N deposition targets for the NFW region. According to this approach, more than 9000 ha (15%) 
in the NFW region is targeted at nature area with critical N depositions ranging from 400 mol N/ha/y to 2500 
mol N/ha/y.  The EU threshold of 50 mg NO3/L was adopted (EC, 1991) as a goal for nitrate concentrations 
in the upper groundwater for all soil types. For surface water quality, the EU Water Framework directive 
specifies a good ecological and chemical quality to be reached by 2015. At EU level, no specific thresholds 
are specified but the Dutch Commission on Integrated Water management has specified thresholds for N and 
P. For the summer-period (April 1 – October 1) for stagnant surface waters, the N concentration limit is set at 
2.2 mg N/L whereas the P concentration limit is set at 0.15 mg P/L. 
 
Material and methods 
Calculations for the emission of NH3 and the deposition of N in the NFW were performed for 2004 with the 
integrated nutrient model Initiator2 in combination with the atmospheric OPS transport model (Jaarsveld 
2004).  Nationally available GIS datasets were used as inputs, including the 1: 50,000 scale soil and 
hydrology map, the LGN land use map, the GIAB dataset on animal numbers and the national parcel 
registration system. A distribution module was included to simulate the application of manure N to the 
individual fields. The model STONE was used for mapping soil chemical characteristics at a spatial 
resolution of 250x250 m which was used as input for the INITIATOR model. 
 
An assessment of water quality in the region with regard to N and P was done using a combination of 
modelling and measurements. The monitoring network from the regional Water Board for surface water 
yielded monthly data for the years 2000 to 2005 for six locations in the NFW area, four locations were in the 
peat area; one location was in the clay area; and one location was in the sand area. These data can be used for 
status monitoring through time (trend monitoring) but are not suitable for compliance monitoring that is 
requested by the Water Framework Directive (Knotters and Brus 2008).  
 
Monitoring data on nitrate concentrations in the upper groundwater at the provincial scale were not available. 
NO3 concentrations in the upper groundwater and N and P loading of surface waters were modelled using the 
STONE model. Additionally, a validation was performed for nitrate concentration in the upper groundwater 
for farms on sandy soils (Sonneveld et al. 2010). 
 
Results 
Both NH3 emissions from point locations (stables, storage) as well as emissions from fields (manure 
application) appear to be uniformly distributed throughout the area. Within relatively small distances (< 1 
km) large variations in field emissions can be found however ranging from < 10 kg NH3-N/ha/y to > 40 kg 
NH3-N/ha/y. For 2004, a total emission of 2.4 kton NH3/yr was calculated. This implies that for 2004 there 
was no exceedance of the downscaled EU NEC goal (2.6 kton NH3/yr) for the NFW region.  
 
The largest rates of atmospheric inputs of N are calculated for the central-eastern part of the study area (> 30 
kg N/ha/y). Calculated deposition rates for most of the area are between 5 to 10 kg N/ha/y. Apart from 
agricultural sources inside the NFW region, also other (industrial) sources and sources outside the NFW area 
© 2010 19th World Congress of Soil Science, Soil Solutions for a Changing World 
1 – 6 August 2010, Brisbane, Australia.  Published on DVD. 
101 
contribute to the total N deposition (Table 1). It appears that a major part of the N deposition, 72%, 
corresponding with 17.5 kg N/ha/y, is due to non-agricultural sources and NOx sources outside the NFW 
region. Accordingly, less than a third of the total N deposition comes from agricultural sources within the 
NFW region. Especially in the central part of the region, the Initiator2 model calculates for 2004 N 
deposition levels that exceed the critical levels substantially. For 2004, critical N deposition values are 
exceeded on almost 53% of the total area with (planned) nature. 
 
Table 1. Sources for N deposition in the study area in 2004. 
Deposition Sources 
(kg N/ha/y)  (%) 
     
Total NOx deposition + NH3 from non-agricultural  
sources (background) 
 17.5  72 
NH3 from stables and storage facilities 2.7  11  
NH3 from land application of manure 4.2  17  
Total NH3 deposition from agriculture  6.9  28 
     
Total N deposition  24.5  100 
 
Calculated average NO3 concentrations are below the 50 mg/L threshold throughout the entire year. Over the 
entire year, the NO3 concentration fluctuates more or less between 10 and 30 mg/L with an annual average 
of 15 mg/L. Thus, the 50 mg/L threshold is for the entire NFW region not exceeded on an annual basis. Low 
NO3 concentrations are especially found in areas with peat and clay soils, probably due to higher 
denitrification rates, whereas higher NO3 concentrations, sometimes locally exceeding the 50 mg/L 
threshold, are mostly found in the (drier) sandy regions.  For the period 2000-2005 a downward trend was 
observed for N and P in surface water, with some fluctuations between the years. For 2005, the median N 
concentration was below the 2.2 mg/L threshold but the upper boundary of the confidence interval exceeded 
this threshold for the previous years. For P, all median concentrations in the surface water were below the 
0.15 mg/L threshold. 
 
Conclusions 
In the NFW study area, the down-scaled national NH3 emission goal for 2010, based on the NEC directive, 
is not exceeded in 2004. However, simulation results suggest that critical N deposition rates on nature areas 
are exceeded on more than half of the area (53%), mainly as a result from non-agricultural sources and 
sources outside the NFW region. For the region as a whole, annual NO3 concentrations in the upper 
groundwater almost never exceed the EU threshold of 50 mg/L. The national N standards for surface water 
regarding N and P are only slightly exceeded for the summer period and monitoring data indicates a 
decreasing trend in time.  From the viewpoint of self-governance, monitoring by regional organizations has 
the most potential for indicators that are related to sources. Environmental monitoring networks should 
preferably be maintained by formal (governmental) institutions, also because of monitoring obligations. 
There is room for developing simple monitoring kits for farmers with the aim to establish feedback loops 
between monitoring and their farming strategies. 
 
References  
Bal D, Beije H, Van Dobben HF, Hinsberg H (2006) ‘Overzicht van kritische stikstofdeposities voor 
natuurdoeltypen’. In: LNV, Directie Kennis, Ede. 
Bruns DA, Wiersma GB (2004) Conceptual Basis of Environmental Monitoring Systems: A Geospatial 
Perspective. In ‘Environmental monitoring. Boca Raton, FL [etc.]’ (Ed Wiersma GB), pp. 631-647. CRC. 
De Gruijter JJ, Brus DJ, Bierkens MFP, Knotters M (2006) Sampling for Natural Resource Monitoring. 
Springer, Berlin. 
De Vries W, Kros H, Oenema O, De Klein J (2003) Uncertainties in the fate of nitrogen II: A quantitative 
assessment of the uncertainties in major nitrogen fluxes in The Netherlands. Nut. Cycl. in Agr. 66, 71-102. 
Jaarsveld JA (2004) The Operational Priority Substances model. Description and validation of OPS-Pro 4.1. 
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Knotters M, Brus DJ (2008) Sampling design for compliance monitoring of surface water quality: A case 
study in a Polder area. Water Resources Research 44, doi:10.1029/2007WR006123 
Sonneveld MPW, Brus DJ, Roelsma J (2010) Validation of regression models for nitrate concentrations in 
the upper groundwater in sandy soils. Environmental Pollution 158, 92-97. 


Conceptual Basis of Environmental Monitoring Systems: A Geospatial Perspective.

Overzicht van kritische stikstofdeposities voor natuurdoeltypen’. In: LNV, Directie Kennis,

Sampling design for compliance monitoring of surface water quality: A case study in a Polder area. Water Resources Research 44, doi:10.1029/2007WR006123 Sonneveld MPW,

Sampling for Natural Resource Monitoring.

The Operational Priority Substances model. Description and validation of OPS-Pro 4.1. In:

Uncertainties in the fate of nitrogen II: A quantitative assessment of the uncertainties in major nitrogen fluxes in The Netherlands.

Environmental monitoring in heterogeneous soil-landscapes; A Dutch case study

Environmental monitoring in heterogeneous soil-landscapes; A Dutch case study

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