Intensive agriculture is characterised by high animal densities
and high levels of plant production. In some regions of Europe
the fodder needs of livestock greatly exceed plant production
so that considerable amounts of feeds have to be imported from
other regions.
About one fourth to one fifth of the P and N in fodder leaves
the agricultural system through animal products. The remainder
is excreted from the animals and mainly spread on agricultural
lands as animal manure. Much of the manure N is lost from the
agroecosystem by volatilisation and leaching, however P, with
its lower mobility, largely accumulates in the surface soil.
This accumulation is beneficial if the P fertility of the land
needs improvement. However, in parts of Europe the soil P content
is now much greater than that needed by the crops. This increases
the risk for P losses to the hydrosphere by leaching and erosion.
In large areas of the Netherlands the soil may now be saturated
with P so that P added in excess of crop uptake leaches from
the soil (Van Boheemen, 1987; Breeuwsma and Silva, 1992).
We here attempt a P-balance of the agricultural system in
all European (except the former Soviet) countries. Legislation
by some countries on the application of animal manure to agricultural
land will be presented. The effects of such policy interventions
on P accumulation will be discussed in the context of economic
considerations.
P compartments and flows
There are three main compartments in the agricultural P cycle,
namely animals, soils and crops. In addition, two storage compartments,
one for animal excreta and one for plant products, feeds and
mineral supplements are used to obtain a comprehensive view of
P flows inside, and into and out of the system (Figure 1). However,
only those compartments and flows with the most significant influence
on the P accumulation in soils will be considered.
It is possible to obtain a fair estimate of most of the P
amounts and flows on a farm scale, but this is more difficult
on a national scale. The simplest national agricultural
balance of P is obtained by calculating the P input through mineral
fertilizers, mineral supplements and imported fodder and subtract
the P output through animal and plant products. Such balances
have been computed for the
Netherlands and W. Germany by Isermann (1990), for E. Germany
by Harenz (1989 a,b) and for Ireland by Tunney (1990). More detailed
balances including estimates of P in fodder, animal excreta and
harvested crops were made by Sibbesen (1989) for seven EC countries.
He used the output of P in animal products to calculate P in
fodder and excreta, a method which facilitates the calculation
of P flows through various animal groups like cattle, pigs and
poultry. This method will be used here.
Figure 1. Phosphorus cycling in agriculture.
Data sources and calculation method
Information about livestock numbers and production of animal
products were obtained from FAO (1991d). From this information
the P excreted in animal manure was calculated. The P excretion
per animal varies considerably between animal species but also
from animal to animal within the same species depending on feeding
intensity (Koefoed and Hansen, 1990). However, the fraction of
fodder P excreted by an animal species seems to vary less with
feeding intensity (Koefoed and Hansen, 1990). Consequently, the
fraction of fodder P which ends up in the animal products is
also relatively constant. It is difficult to get information
on fodder use in all European countries, especially on the use
of forage. Information on animal production is more easily obtained.
If P leaving agriculture through milk, eggs and animals for slaughter
can be calculated, then it is straightforward to calculate the
input of P in fodder and output of P through excreta provided
the distribution coefficients between animal products and excreta
are known.
Table 1. Values used for P concentration,
carcass fraction (fca) and distribution of fodder P on excreta
(Pe) and animal products (Pa) (milk, eggs and animals sent for
slaughter). The P concentration values refer to live animals
including contents of digestive and urinary tracts. For mammals,
the carcass fraction is the weight of dressed carcass relative
to live weight. For poultry it is the ready-to-cook weight relative
to live weight.
|
|
P concentration |
Carcass fract. |
Distribution |
|
|
mgkg-1 |
Refs. |
fca |
Refs. |
Pe |
Pa |
Refs. |
|
Cow milk |
1.0 |
1, 2 |
|
|
77 |
23 |
19, 22 |
|
Sheep milk |
1.5 |
2 |
|
|
77 |
23 |
22 |
|
Goat milk |
1.2 |
2 |
|
|
77 |
23 |
22 |
|
Eggs with shell |
1.9 |
3,4 |
|
|
80 |
20 |
21 |
|
|
|
|
|
|
|
|
|
|
Cattle |
7.1 |
5,6,7,8,9,10 |
0.47 |
15 |
78 |
22 |
18,19,20 |
|
Pigs |
5.5 |
5,11,12,13 |
0.70 |
16 |
76 |
24 |
18,19,20 |
|
Sheep, goats |
5.0 |
5 |
0.47 |
22 |
77 |
23 |
22 |
|
Horses |
7.0 |
18 |
0.60 |
22 |
77 |
23 |
22 |
|
Poultry |
5.8 |
5, 14 |
0.82 |
17 |
58 |
42 |
14, 21 |
1) Andersen and Just (1983),
2) Ling (1961), 3) Bergquist (1979), 4) Simons (1986), 5) Günther
(1972), 6) Agricultural Research Council (1984), 7) Ellenberger
et al. (1950), 8) Schulz et al. (1974) 9) Nørgaard
(1989), 10) Van Soest (1983) 11) Jørgensen et al.
(1984) 12) Jørgensen et al. (1986), 13) Just et
al. (1985), 14) Håkansson et al. (1983), 15)
LIK (1986a), 16) LIK 1985), 17) LIK (1986b), 18) Sibbesen (1989),
19) Koefoed and Hansen (1990), 20) Sibbesen (1990), 21) M.G.
Thomsen, pers. comm., 22) Estimated.
For a given animal group the amount of P removed in live animals
(Pla) sent for slaughter is calculated from the equation
Pla = Qmfca-1cla
where Qm is the quantity of meat based on dressed carcasses
excluding offal and slaughter fat (FAO, 1991d), fca is the carcass
fraction (comparable to dressing %, Beaton et al., Ch.
2), i.e. the mean weight of dressed carcasses relative to that
of live animals and cla is the mean P concentration of live animals.
cla is calculated from the equation:
cla = feacea + fgicgi + fucu
where fea, fgi and fu are the mean weight of respectively
empty animal, gastrointestinal content and urine relative to
that of live animal, and cea cgi and cu are the mean P concentration
of respectively empty animal, gastrointestinal content and urine
(Sibbesen, 1990). The P concentrations, carcass fractions and
distribution coefficients in Table 1 were used here.
Calculation of P in harvested crops is straightforward if
crop coverage, yields and P concentrations are known. Coverage
and yields of crops, were obtained from FAO (1991d), Eurostat
(1989) and national agricultural statistical tables. Yields of
forage crops could not be found for most countries outside the
EC, so they were estimated. P concentrations were taken from
Andersen and Just (1983) and Nehring et al. (1972).
All calculations are based on 1989 data except for the yields
of crops which are based on four years (1986-1989) to partly
compensate for year to year variations. Country divisions existing
in 1989 are used. The data are presented relative to the area
of total agricultural (crop and pasture) land.
Land use
To place European agriculture in a global scale, some land
use parameters of world divisions are shown in Table 2. European
agriculture only covers 4.5% of the world agricultural area,
but 60% of Europe’s agricultural area is arable, indicating
an intensive mode of production. Arable areas generally receive
more nutrients and are more prone to P losses by surface runoff
and wind erosion than permanent grassland areas. Denmark has
the largest proportion of arable land and Iceland the least (Table
3). Poland, Czechoslovakia, E. Germany and Hungary also have
relatively large proportions of arable land.
Table 2. Land use of continents in 1989 (FAO,
1991d).
|
|
Total land area |
Agricultural area
Total Arable2 Grass3 |
agric.
of total |
arable
of agric. |
agric.
of world |
|
|
---------------1,000,000 ha--------------- |
-------------%------------- |
|
N + Centr America |
2138 |
636 |
267 |
369 |
30 |
42 |
14 |
|
South America |
1753 |
595 |
116 |
479 |
34 |
19 |
13 |
|
Europe1 |
473 |
209 |
126 |
83 |
27 |
60 |
4.5 |
|
Africa |
2964 |
1059 |
168 |
891 |
36 |
16 |
23 |
|
Asia |
2678 |
1099 |
420 |
678 |
41 |
38 |
23 |
|
Oceania |
843 |
482 |
50 |
432 |
57 |
10 |
10 |
|
USSR |
2227 |
597 |
226 |
371 |
27 |
38 |
13 |
|
|
|
|
|
|
|
|
|
|
World |
13076 |
4677 |
1373 |
3304 |
36 |
29 |
100 |
1 Europe except European
part of USSR.
Stocking rate and P in animal products
The animal density is far greater in Europe than in other
world divisions (Figure 2). The P flow through the animals is
a key parameter with respect to P fertilisation of the land.
The estimated amounts of P leaving agriculture through animal
products (Table 4) vary greatly between countries. The Netherlands
are on an absolute first place delivering almost twice as much
as number two Belgium+Luxembourg which again deliver almost twice
as much as Denmark and W. Germany. Norway, E. Germany and Switzerland
are also positioned well above the European mean while Mediterranean
and Balkan countries except for Italy are positioned well below.
Figure 2. Animal density based
on total agricultural area for world regions in 1989 based on
FAO (1991).
P in animal excreta and mineral fertilizers
In the production of P in animal excreta, countries range
in the same order as with P in animal products (Table 4). In
the Netherlands and Belgium+Luxem-bourg the average production
rate is much higher than the amounts normally taken up by crops.
Monogastric animals like pigs and poultry can be raised on purchased
feed in factory farms without associated land. Ruminants, i.e.
cattle sheep and goats, normally need land for producing the
forage on which they are normally raised. The high excretion
rates of P from ruminants in the Netherlands and Belgium+Luxembourg,
however, indicate that they are largely raised on purchased feeds.
P in mineral fertilizers is ideally used as a supplement to
P in animal manure. One should therefore expect little use of
mineral phosphate fertilizers in countries producing much excreta
P and vice versa. The opposite, however, is observed: countries
producing much excreta P generally also apply much mineral fertilizer
P (Table 4). Mediterranean and Balkan countries, producing little
excreta P, also used little mineral fertilizer P. The average
total P fertilisation rate was 25 kg ha-1
y-1 for all Europe and ranged from 79 kg ha-1 y-1 in the Netherlands
to 1 kg ha-1 y-1 on Iceland (Table 4, Figure 3).
Figure 3. Total P fertilisation
for all agricultural land in Europe in 1989.
CROP REMOVAL AND NET P FERTILISATION
Crop removal of P with harvests was around 20 kg P ha-1 y-1 at the most, i.e. in Denmark, the Netherlands,
Belgium+Luxembourg and W.Germany (Table 5). Crop removal in the
Mediterranean and Balkan countries generally was less than 10
kg P ha-1 y-1. The key figure for an environmental balance sheet
is the net P fertilisation rate, calculated as the difference
between total fertilisation and crop removal. It was positive
for all European countries indicating a steady P enrichment of
European soils (Figure 4 and Table 5). However, the enrichment
rates varied greatly between countries with the Netherlands and
Belgium+Luxembourg having extreme values of 57 and 42 kg P ha-1
y-1 respectively. West and East Germany and Czechoslovakia also
had large net fertilisation rates of well above 20 kg P ha-1
y-1.
Table 4. P removed in animal products (milk,
eggs, animals for slaughter, dead animals), P in excreta (faeces
+ urine) from various animal groups, use of P in mineral fertilizers
and total P fertilisation over the total agricultural area in
1989.
|
Country |
animal |
in excreta from |
miner. |
all |
|
|
prods. |
cattle sheep goats horses |
pigs |
poultry |
all
animals |
fert. |
fert. |
|
|
-------------------------------
kg P ha-1 y-1 ------------------------------ |
|
Iceland |
0.1 |
0.4 |
0.0 |
0.0 |
0.5 |
1.1 |
1.6 |
|
Norway |
4.4 |
12.0 |
2.2 |
0.6 |
14.8 |
16.2 |
31.0 |
|
Sweden |
2.6 |
5.7 |
2.3 |
0.4 |
8.4 |
8.9 |
17.3 |
|
Finland |
2.5 |
6.1 |
1.8 |
0.3 |
8.2 |
24.3 |
32.5 |
|
Denmark |
6.7 |
10.1 |
10.8 |
0.7 |
21.5 |
15.6 |
37.2 |
|
|
|
|
|
|
|
|
|
|
Ireland |
2.7 |
8.3 |
0.6 |
0.2 |
9.1 |
11.5 |
20.6 |
|
U.K. |
2.9 |
6.8 |
1.4 |
0.9 |
9.0 |
10.5 |
19.4 |
|
Netherlands |
19.5 |
31.7 |
25.1 |
4.8 |
61.6 |
17.5 |
79.0 |
|
B.+ Luxemb. |
11.7 |
22.4 |
13.1 |
2.1 |
37.6 |
25.4 |
63.0 |
|
France |
2.9 |
6.9 |
1.5 |
0.7 |
9.1 |
22.1 |
31.3 |
|
|
|
|
|
|
|
|
|
|
W. Germany |
6.8 |
14.9 |
6.7 |
0.9 |
22.4 |
22.2 |
44.6 |
|
E. Germany |
5.2 |
10.0 |
6.2 |
0.7 |
17.0 |
26.2 |
43.2 |
|
Poland |
2.5 |
5.3 |
2.5 |
0.4 |
8.2 |
17.8 |
26.0 |
|
Czechoslov. |
3.6 |
7.3 |
3.6 |
0.7 |
11.7 |
31.4 |
43.1 |
|
Switzerland |
4.6 |
11.2 |
3.6 |
0.3 |
15.1 |
8.5 |
23.7 |
|
|
|
|
|
|
|
|
|
|
Austria |
3.2 |
7.0 |
3.0 |
0.4 |
10.4 |
9.4 |
19.8 |
|
Hungary |
2.9 |
3.1 |
4.4 |
1.0 |
8.5 |
19.8 |
28.3 |
|
Portugal |
1.8 |
3.7 |
1.5 |
0.5 |
5.7 |
9.7 |
15.3 |
|
Spain |
1.4 |
2.1 |
1.6 |
0.5 |
4.3 |
9.5 |
13.8 |
|
Italy |
3.3 |
6.6 |
2.2 |
1.2 |
10.0 |
19.1 |
29.1 |
|
|
|
|
|
|
|
|
|
|
Yugoslavia |
1.5 |
2.8 |
1.5 |
0.4 |
4.7 |
7.5 |
12.2 |
|
Romania |
1.4 |
2.1 |
1.6 |
0.5 |
4.1 |
11.0 |
15.1 |
|
Bulgaria |
1.8 |
3.3 |
1.8 |
0.5 |
5.7 |
16.4 |
22.1 |
|
Albania |
1.4 |
4.2 |
0.2 |
0.3 |
4.7 |
10.8 |
15.4 |
|
Greece |
0.9 |
2.0 |
0.5 |
0.3 |
2.8 |
10.1 |
12.9 |
|
|
|
|
|
|
|
|
|
|
Europe |
2.9 |
6.0 |
2.6 |
0.7 |
9.3 |
15.6 |
24.9 |
|
EC-12 |
3.3 |
6.9 |
2.7 |
0.8 |
10.4 |
15.6 |
26.0 |
Figure 4. Net P fertilisation for all agricultural
land (total fertilisation minus crop removal) in European countries
in 1989.
FODDER P
The use of fodder in the Netherlands and Belgium+Luxembourg
was much greater than the amounts produced on their own land,
requiring a large import of fodder (Table 5). Also Norway, Denmark,
W.Germany, E.Germany and Switzerland showed a net import of fodder
whereas France and Sweden appeared to be net exporters. For all
Europe fodder use and production seemed to balance.
Evaluation of P flows and environmental
loads
The P flows presented are naturally open to debate as there
are many approximations and limitations in calculations of this
scale. However, the net fertilisation rates calculated compare
reasonably well with net import calculations for E.Germany (Harenz,
1989 a,b), W.Germany (Isermann, 1990) and Ireland (Tunney, 1990).
The 57 kg P ha-1 y-1 calculated here for the
Netherlands is greater than the 36 kg P ha-1 y-1 calculated by
Isermann (1990). Part of the reason for this discrepancy may
be that Dutch agriculture has been addressing the P-surplus problem
now for some years. Fine-tuning of P feeding norms and increasing
utilization of phytate P in the fodder may have reduced the fraction
of P excreted from the animals (Jongbloed and Lenis, 1992). In
the Netherlands a small part of the manure is also processed
into marketable fertilizers part of which may leave agriculture.
Table 5. P removed in crops (harvested
or grazed), net P fertilisation (all fertilizer P minus P removed
in crops), and P in fodder. Net import or export of P in fodder
is the difference between P amounts in total fodder used, and
potential fodder available from crop removal, 1989.
|
|
|
|
P in fodder |
|
Country |
Crop
removal |
Net fertilisation |
Total |
Net
import |
Net
export |
|
|
|
|
|
|
|
|
|
------------------------- kg P ha-1
y-1 ------------------------- |
|
Iceland |
0.9 |
0.7 |
0.6 |
|
0.3 |
|
Norway |
15.0 |
15.9 |
19.2 |
4.2 |
|
|
Sweden |
15.0 |
2.3 |
11.0 |
|
4.1 |
|
Finland |
11.9 |
20.6 |
10.7 |
|
1.2 |
|
Denmark |
21.7 |
15.5 |
28.3 |
6.6 |
|
|
|
|
|
|
|
|
|
Ireland |
12.2 |
8.4 |
11.8 |
0.4 |
|
|
United Kingdom |
14.1 |
5.4 |
11.9 |
|
2.2 |
|
Netherlands |
21.8 |
57.2 |
81.0 |
59.2 |
|
|
Belgium+Luxemb. |
21.5 |
41.5 |
49.3 |
27.8 |
|
|
France |
16.6 |
14.6 |
12.0 |
|
4.6 |
|
|
|
|
|
|
|
|
W. Germany |
20.2 |
24.4 |
29.2 |
9.0 |
|
|
E. Germany |
17.7 |
25.5 |
22.1 |
4.4 |
|
|
Poland |
12.0 |
14.0 |
10.8 |
|
1.2 |
|
Czechoslovakia |
16.5 |
26.6 |
15.3 |
|
1.2 |
|
Switzerland |
13.1 |
10.6 |
19.7 |
6.6 |
|
|
|
|
|
|
|
|
|
Austria |
13.5 |
6.3 |
13.6 |
0.1 |
|
|
Hungary |
12.8 |
15.5 |
11.3 |
|
1.5 |
|
Portugal |
7.8 |
7.5 |
7.5 |
|
0.3 |
|
Spain |
7.3 |
6.5 |
5.7 |
|
1.6 |
|
Italy |
12.1 |
17.0 |
13.3 |
1.2 |
|
|
|
|
|
|
|
|
|
Yugoslavia |
7.6 |
4.6 |
6.2 |
|
1.4 |
|
Romania |
7.6 |
7.5 |
5.5 |
|
2.1 |
|
Bulgaria |
9.5 |
12.6 |
7.5 |
|
1.9 |
|
Albania |
7.9 |
7.5 |
6.1 |
|
1.8 |
|
Greece |
5.7 |
7.3 |
3.7 |
|
2.0 |
|
|
|
|
|
|
|
|
Europe |
12.3 |
12.6 |
12.3 |
|
0.1 |
|
EC - 12 |
13.2 |
12.8 |
13.7 |
0.5 |
|
There is, however, no doubt that agricultural land in many
parts of Europe receives much more P than needed by the crops
with the effect that the soil is accumulating P. It should be
borne in mind that the figures presented are averages and that
the surplus P is unevenly distributed. Some regions within a
country, farms within a region and fields within a farm receive
much more P than the country rates presented. At farm level,
the arable land generally receives more animal manure than permanent
grassland. The aforementioned paradox that countries producing
much excreta P also use much mineral fertilizer P is due to a
division of different regions and farms into cereal and animal
production. Transport of animal manure is costly and therefore
limited. Therefore, animal producers are inclined to spread their
animal manure on their own land and grain growers are inclined
to use mineral fertilizer P. For many years the common agricultural
policy in EC countries guaranteed high prices for cash crops
like cereals and rapeseed, which enabled farmers in the more
fertile areas to live solely by this production. This resulted
in a "movement" of the animal production towards less
fertile, regions with sandy soils, so that sandy soils generally
receive more animal manure than clay soils. In Denmark this clearly
shows in the soil-P test values determined according to Olsen
et al. (1954). They are greater and increase at a higher
rate in the sandy regions of Vestjylland and Nordjylland than
in more loamy Østjylland, Fyn and Zjælland (Figure
5). The average Olsen P value for Denmark is 46 mg P kg-1 soil, a level which indicates that crop responses
to further P application are not likely (Johnston et al.,
1986). In the Netherlands in the sandy districts Salland-Twente,
West Veluwe, Meijerij and South Peel about half the maize and
grassland should now be saturated with P due to many years of
surplus addition of animal manure (Breuwsma and Silva, 1992).
In the Italian Po region environmental problems due to intensive
animal production have been reported (Breuwsma and Silva, 1992),
although the national Italian production of excreta P is low
(Table 4). High local nutrient loads are also found in France
in Finistère and Côtes d'Armor (L. Gueguen, pers.
comm.)
Figure 5. Average (Olsen, 1954) soil P test
values for Denmark and regions.
Legislation on animal manure in Europe
Legislation has been introduced in a number of European countries
to control application of animal manure. In some of them, e.g.
in Denmark, France and W. Germany the primary aim seems to be
to control nitrogen losses. In others, e.g. the Netherlands and
Belgium legislative regulations are based on P addition. Table
6 shows the maximum permissible P addition from animal manure
in various countries, either stated or calculated from nutrient
ratios. The permitted rates differ greatly between countries
from 14 to 110 kg P ha-1 y-1, i.e. from a
rate equivalent to crop uptake to five times the crop uptake.
When an application rate of N is used as basis for the permissible
application of animal manure it has the effect that more P can
be applied as pig than as cattle manure (Table 6). Moreover,
in some countries permissible rates differ between crops. This
has traditional or technical reasons and is not based on differences
in crop needs. For instance, in the Netherlands and Belgium very
large rates of animal manure have traditionally been applied
to maize because maize can tolerate it. In Germany, specific
"ground water protection areas" have been created where
crop choice and application of mineral fertilizers and organic
manures are restricted, while income losses of farmers are compensated.
These areas cover between 15 and 20% of the German land area,
and have a major impact on environmental nutrient loads.
So far, permissible rates only apply to P in animal manure.
Phosphorus in mineral fertilizers is not included in the regulations
although there is little or no long-term difference between the
two P sources after incorporation into the soil. More than 85%
of the P in animal slurry is inorganic (Gerritse and Vriesma,
1984). Irrespective of P source, less than 10% of the P applied
is taken up by the crops in the application year. The rest accumulates
in the soil and contributes to the increased P fertility, or
load of soils. In addition to limiting application rates, most
countries stipulate time periods when spreading of animal manure
is not allowed, mainly to limit nitrogen losses. To prevent surface
runoff of animal manure it is generally not allowed to apply
it to snow-covered or frozen ground. Most countries also prescribe
immediate incorporation of applied animal manure.
The EC Council put forward an EC Nitrate Directive (EEC/91/676)
in 1991 prescribing actions to control nitrate leaching from
vulnerable regions. Member states are committed to formulate
codes for good agricultural practices and to establishes rules
for time periods for applying animal manure, for storage of animal
manure and for limitations on total nutrient application. A maximum
permissible rate for animal manure equivalent to 170 kg N ha-1 y-1 has been stipulated. This equals 19 and
43 kg P ha-1 y-1 respectively for cattle and pig manure. However,
during a transitional period of four years 210 kg N ha-1 y-1
equivalent to 24 and 53 kg P ha-1 y-1 is allowed, and higher
application rates will be permitted if they can be justified.
The EC Commission recently hosted an expert workshop on codes
of good agricultural practices (Bonde, 1992). The Commission
expressed concern about the negative impact on the environment
of present animal husbandry practices, intensive use of fertilizers
and degree of mechanisation. The experts agreed that a combined
use of regulatory, advisory and financial instruments was necessary
to regulate agriculture efficiently. As to regulatory measures
the experts concluded that a maximum livestock density of animal
holdings should be based on a maximum application rate of P (or
potassium) in animal manure corresponding to the average need
of common crop rotations of the EC member states.
Table 6. Legislative permissible addition
of P through animal manure. P rates with asterisk are calculated
from permissible animal density or permissible nitrogen addition
through animal manure assuming excretion of 127 kg N y-1 and 14.5 kg P y-1 from one dairy cow
and 4.0 kg N and 1.0 kg P from one fattening pig delivered (Koefoed
and Hansen, 1990).
|
Country |
Year |
Crops |
Permissible
animal density |
Permissible addition of nutrients in
animal manure |
|
|
|
|
|
|
Nitrogen Phosphorus |
|
|
|
|
Cows1 |
Pigs2 |
|
Cows |
Pigs |
Avg. |
|
|
|
|
numbers ha-1 |
------------- kg ha-1
y-1 ----------- |
|
|
|
|
|
|
|
|
|
|
|
Norway |
1989 |
all |
2.54 |
84 |
|
36* |
24*3 |
32* |
|
Sweden |
1995 |
all |
1.65 |
105 |
|
23* |
30*3 |
27* |
|
Denmark |
1993 |
all |
2.36 |
13.66 |
|
33* |
41*3 |
37* |
|
Netherlands |
1991 |
arable |
|
|
|
|
|
557 |
|
|
|
maize |
|
|
|
|
|
1107 |
|
|
|
grassland |
|
|
|
|
|
887 |
|
|
1995 |
arable |
|
|
|
|
|
557 |
|
|
|
maize |
|
|
|
|
|
767 |
|
|
|
grassland |
|
|
|
|
|
767 |
|
Belgium |
|
|
|
|
|
|
|
|
|
Flanders |
1991 |
arable |
|
|
|
|
|
658 |
|
|
|
maize+grassland |
|
878 |
|
France |
|
|
|
|
|
|
|
|
|
Finistère |
1991 |
arable |
|
|
2008 |
23* |
50* |
37* |
|
|
|
grassland |
|
|
3508 |
40* |
88* |
64* |
|
C. d'Armor |
1991 |
arable |
|
|
2008 |
23* |
50* |
37* |
|
|
|
grassland |
|
|
3508 |
40* |
88* |
64* |
|
W.Germany |
|
|
|
|
|
|
|
|
|
Schlesw.-H |
1991 |
all |
|
|
1608 |
18* |
40* |
29* |
|
NR Westf. |
1993 |
all |
|
|
2008 |
23* |
50* |
37* |
|
Nd-Sachs. |
1993 |
all |
|
|
2008 |
23* |
50* |
37* |
|
Bd.Würt. |
1991 |
maize |
|
|
1258 |
14* |
31* |
23* |
|
|
|
grassland |
|
|
2248 |
26* |
56* |
41* |
1 Dairy
cows with no young stock. 2 Number of places for fattening pigs.
3 Assuming three pigs delivered per place and year. 4 Landbruksdepartementet
(1989).
5 Lantbruksstyrelsen (1989). 6 Miljøministeriet (1992).
7 Van Boheemen (1987).
8 Schröder (1992).
Economic aspects of policy interventions to reduce P emission
in livestock intensive production area
The high P emissions from animal intensive farming systems
in parts of Europe create a need to reduce P-flows from soils
to water bodies at a cost acceptable to society. Environmental
economics provides different solutions ranging from statutory
government interventions (bans or regulations) to more market
oriented instruments (taxes, quotas, pollution certificates,
direct negotiations) (Pearce and Turner, 1990; Cropper and Oates,
1992). Most economists prefer the market approach while most
governments opt for legislative measures. There is no clear evidence
that any one approach is superior (Scheele et al., 1992).
The suitability of any intervention depends on certain characteristics
of the environmental problem to be tackled which affect transaction
costs and control costs. Negotiations, as a market oriented instrument,
may not be practicable. It will be difficult to identify specific
people who are affected by phosphate pollution since surface
waters are more or less public goods. Current consumer wealth
may be affected by effects on tourism or property values near
eutrophic lakes, but the environmental damage may only occur
after a considerable time lag so that the interests of future
generations are violated. In general, the large number of people
who are affected results in great transaction costs for negotiations.
It is therefore justifiable that the government take the initiative
as a 'custodian' of the interests of current consumers and future
generations.
Control costs are incurred in the supervision of any policy
measure. A measure’s ability to solve an environmental problem
depends primarily on the number and kind of polluting sources
which also determine the environmental parameters to be monitored.
Non-point sources of pollution are an important part of P fluxes
since any agricultural field is a potential P source. Phosphorus
losses from fields may be controlled by setting specific limits
for maximum "mobile" soil P contents in relation to
local characteristics such as soil type, topography etc. For
cost reasons, only a limited number of checks on such soil-P
levels can be made on agricultural lands. The number of checks
necessary depends on the stability of the parameter to be monitored.
Controls must also be accompanied by sanction mechanisms to be
effective.
In practice, many governments prefer to intervene at the farm
level by limiting the number of animals per hectare. In most
cases of existing legislation, the number of livestock units
per hectare is fixed irrespective the agricultural land use and
the yield potential of the specific location. This may lead to
substantial economic inefficiencies because the economic potential
of many areas may not be optimally used and because it is not
assured that organic manure is really distributed according to
the location-specific capacity to store or assimilate P. Therefore,
effective control measures must consider soil properties and
include soil analyses. Current legislation is unlikely to address
the P-problem effectively.
Legislative measures are often accompanied by market-oriented
policy instruments like the taxation of nutrients provided through
mineral fertilizer. The experience of different European countries
shows that taxation is an effective measure to reduce the use
of mineral fertilizer. Farm incomes have not been curtailed substantially
by this measure which indicates that fertilizer, in particular
organic manure, was used inefficiently before. Potential income
declines can be reduced when such taxes are transferred back
to the agricultural sector (Becker, 1992). A more drastic measure
to reduce mineral fertilizer use is to impose fertilizer production
and trade quotas at the national or regional level. This would
lead to a general rise of fertilizer prices (Scheele et al.,
1992). Although the general impact on the environment will be
positive in Europe, neither measure addresses the P problem of
intensive livestock production areas specifically.
More specific options to counteract the environmental threats
of P are available. Subsidies for the investment into specific
equipment can be used, e.g. for stores for organic manure etc.
Certificates or licenses can be granted for any piece of agricultural
land to allow the application of a certain amount of nutrients
according to crop removal and to natural conditions of the field.
The farmer has to keep records with regard to animal husbandry
(livestock numbers, purchased feeds, products sold) and field-related
information (timing of application and amount of animal manure,
mineral fertilizer, crop rotations etc.). The farmer then has
to ensure that the potential output of manure-P does not exceed
the certified amount of P he can apply. Transfers of animal manure
in exchange for the certificate to neighbouring farmers, other
persons or companies will be explicitly allowed. In this market,
anyone could buy certificates, for instance, in order to reduce
the application of animal manure to agricultural land near areas
where the amenity value of a clean lake is high. This system
is costly for farmers who will have to keep records, but better
information with respect to nutrient balances could substantially
improve farmers' ability to manage natural resources more effectively
and thereby reduce over-fertilisation (Schindler, 1990). 'Nutrient-bookkeeping'
is likely to be introduced in the Netherlands at the beginning
of 1995 when excessive amounts of P will be taxed (Agra-Europe,
1993).
Environmental problems have to be assessed holistically, otherwise,
solving one environmental problem may create a new one at a different
level. For instance, the introduction of licenses for the land-disposal
of animal manure may increase intra-regional transport of animal
manure. This will lead to higher emissions through increased
rural traffic, and to new externalities, in particular, when
transport is subsidised in rural areas (road network, tax abatement
on agricultural vehicles and oil). Thus, careful examination
of secondary effects of environmental policies is indispensable.
Phosphorus emissions from agricultural land from surface runoff
and wind erosion can only partially be controlled through the
determination of a maximum permissible soil P content. Agricultural
practices also must be changed to reduce surface runoff and wind
erosion to acceptable levels. Usually, surface runoff and wind
erosion are checked by clearly visible cultural measures (e.g.
crop choice, wind breaks, grass strips etc.), and government
regulations ('good agricultural practice') with respect to such
measures can be easily imposed and controlled.
It will not be easy to arrive at the most cost-effective combination
of environmental policies, in particular when the interests and
incomes of small, but well-organised pressure groups like the
EC farmers are affected negatively. Social unrest may be the
consequence as seen during the reform of the EC common agricultural
policy associated with the GATT negotiations, or the opening
of the common market for agricultural imports from the East.
It must be noted that economic welfare theory does not provide
an answer to the question how welfare gains of an efficient environmental
policy are distributed among the members of the society as long
as distributional policies do not affect the efficient allocation
of resources. In principle, direct financial compensation of
farmers does not influence the outcome of an environmentally
efficient policy as long as no major administrative costs are
involved.
Acknowledgment
Thanks are due to A. Metherell, AgResearch, New Zealand and
L. Gueguen, INRA, France for valuable criticism of the manuscript.
|
Phosphorus in the Global Environment.
Edited by H. Tiessen
© 1995 SCOPE. Published in 1995 by John Wiley &
Sons Ltd. |
|
Last updated: 12.07.2001