Geerts, R.H.E.M.

Korevaar, H.

Visser, W., de

Name not available

Multifunctional land use and its impact on the nitrate concentration in groundwater under grassland

Wageningen Yield 

313
Multifunctional land use and its impact on the nitrate 
concentration in groundwater under grassland  
Korevaar, H.*, Geerts, R.H.E.M. & Visser, W. de
Plant Research International, P.O. Box 16, 6700 AA Wageningen, the Netherlands 
* E-mail: hein.korevaar@wur.nl 
Abstract
During three years data of six grassland types were collected on 14 farms. Grass production, number of plant 
species, N fertilization, Nmin in autumn and nitrate leaching in following spring showed a large variation. There was 
no relation between N-fertilization level and Nmin, neither between Nmin in autumn and nitrate concentration in the 
following spring.
Multifunctional land use, including diversification and extensification of grassland, can help to meet the target of 
50 mg nitrate per l in groundwater.  
Keywords: DM production, fertilizer, grassland, leaching, nitrate, nitrogen 
Background and objectives 
The objective of multifunctional land use is to combine different functions (e.g. food production, nature conservation, 
environmental protection and recreation) within one area. Multifunctional land use is considered as an option to 
enlarge the economical and environmental sustainability of an area. In 1998 a large program on sustainable land use 
started in the Winterswijk area. The area consists of a small-scale landscape with a dominant role for agriculture. 
Substantial parts of the area are covered by nature, forests, recreation areas and campsites. The focus of the 
program is: 
? to create more variation in grasslands and arable crops, than only perennial ryegrass swards and silage maize 
? to enlarge the ecological values of farmland 
? to make the area more attractive for recreation and tourism 
? to reduce environmental losses like nitrate leaching.  
Material and methods 
From 2002 till 2004 an intensive monitoring programme was carried out on 14 farms covering a broad range in 
farming types. Relations between fertilization, production, farm income, biodiversity and environmental issues were 
analysed thoroughly.
In this paper we present results of different grassland management types on dry matter production, number of plant 
species, N-fertilization (fertilizer N and effective N from slurry), N harvested in the crop, residual Nmin in autumn and 
nitrate in upper groundwater in the following spring.  
Results and conclusions 
The grasslands were grouped into the six types (Table 1). Total N-fertilization (mainly cattle slurry) on grass-clover 
swards was less than half the amount of fertilized ryegrass swards (which were regarded as a kind of control for the 
ordinary farming system in that region), but the average dry matter production, N-uptake and nitrate concentration 
on grass-clover swards were similar. The average clover content (expressed as ground cover by clover leaves) on 
the grass-clover fields was 33%. 
314
Fertilization levels on the fertilized grass mixtures (of native grasses) and species-rich grasslands (grassland with 
wild flowers) were low. Nitrate concentration in groundwater under grass mixtures and species-rich grasslands 
(fertilized and unfertilized fields) was far below the EU-limit.  
Table 1.  Number of plant species, dry matter yield, N-fertilization, N-uptake, N-min in autumn and NO3-
concentration in groundwater in following spring on different multifunction grassland types in 2002 
to 2004. 
Grassland type  n Number 
of plant
species on 
100 m2
DM
production
t ha-1
N-
fertilization
kg ha-1
N-uptake by 
the grass 
kg ha-1
N-min
autumn
(layer
0-60 cm) 
kg ha-1
NO3 in
upper
ground-
water
mg l-1
NO3
% of fields
<50 mg l-1
Ryegrass;
fertilized 
9 11 12.1 191 370 59 92 33 
Grass-clover 7 8 11.9 84 384 36 95 43 
Grass-mixtures;
fertilized 
5 18 9.3 57 239 29 18 80 
Grass-mixtures; 
unfertilized
6 17 8.1 0 153 25 18 100 
Species-rich;
fertilized 
8 29 9.8 62 235 17 25 75 
Species-rich;
unfertilized
9 21 5.2 0 83 8 5 100 
0
20
40
60
80
100
120
140
160
180
200
0 200 400 600
N fertilization kg ha-1
N
m
in
 k
g 
ha
-1
Ryegrass/
Grass-clover
Grass-mixtures/
Species-rich
Figure 1.  Relation of N fertilization and mineral N in autumn. 
315
0
20
40
60
80
100
120
140
160
180
0 50 100 150 200
Nmin kg ha-1
N
itr
at
e 
m
g 
l-1 Ryegrass/
Grass-clover
Grass-mixtures/
Species-rich
Figure 2.  Relation of mineral N in autumn and nitrate in upper groundwater in the following spring. 
There was no relation between N-fertilization level and Nmin (Figure 1), neither between Nmin in autumn and nitrate 
concentration in the following spring (Figure 2).  
0
20
40
60
80
100
120
140
160
180
0 100 200 300 400 500
N fertilization kg ha-1
Ni
tr
at
e 
m
g 
l-1
Ryegrass/ Grass-
clover
Grass-mixtures/
Species-rich
Figure 3.  Relation of N fertilization and nitrate in upper groundwater in the following spring. 
The relation between N fertilization and nitrate is a complicated one (Figure 3). There were two subgroups in the 
data. The ryegrass and grass-clover swards had a high N input by fertilization, fixation by clover and excretion by 
cattle and most of them (10 of the 16) were located on soils with a good water management (low groundwater 
table). The 28 grass-mixtures and species-rich grasslands had a much lower N input (all < 200 kg N ha-1) and almost 
all these fields (15 of the 28) were situated on wet soils. These fields were not of only a part of the season grazed 
and cut once or twice a year for hay or silage. On wet soils more denitrification may be expected. So the lower 
nitrate concentration under grass-mixtures and species-rich grasslands is explained as a combination of a lower N 
input, less grazing and more denitrification. 
Grass-mixtures and species-rich grasslands are more common on soils with a high groundwater table, for instance 
along brooklets, than grass-clover and fertilized ryegrass fields. A low fertilization with a maximum of 100 kg N ha-1
stimulates grass production to a level that still a high biodiversity is achievable and the nitrate leaching stays at an 
acceptable level. 
316
Conclusions 
Multifunctional land use, more precisely diversification and extensification of grassland, in most cases brings by less 
grass production, but more plant species and more often meeting the target of 50 mg nitrate per l in groundwater. 
A low total N-fertilisation level (on grass-clover swards) however is no guarantee to meet the NO3 target. 
Acknowledgements 
This project is supported by farmer’s organisation LTO Noord, European Agricultural Guidance and Guarantee Fund, 
Province Gelderland and the Ministry of Agriculture, Nature Conservation and Food 


Multifunctional land use and its impact on the nitrate concentration in groundwater under grassland

Abstract

Similar works

Full text

Available Versions

Name not available

Wageningen Yield