6. Consequences for the environment and health, Danish Environmental Protection Agency

Report from the Bichel Committee - Organic Scenarios for Denmark

6. Consequences for the environment and health

6.1	Losses and pollution with nitrogen and phosphorus
6.1.1	Nitrogen
6.1.2	Phosphorus
6.2	Consumption of fossil energy and production of greenhouse gases
6.2.1	Consumption of fossil energy
6.2.2	Greenhouse gases
6.3	Nature content – effect on fauna and flora
6.3.1	Set-aside acreage
6.3.2	Semi-natural ecosystems and small biotopes
6.3.3	Landscape in general
6.4	The biology of the soil
6.5	Health consequences of plant products
6.6	Consumption of veterinary drugs
6.7	Summary and conclusion

This chapter supplements the Bichel Report

This chapter describes the consequences for the environment and health of total restructuring for organic farming in Denmark. The consequences of a phase-out of pesticides are described in the report from the Sub-committee on Environment and Health. In continuation of that, importance is attached here to describing the consequences of the changed crop rotation and the phasing out of artificial fertilisation. This chapter should thus be seen as a supplement to the consequences described in the report from the Sub-committee on Environment and Health. The consequences for the working environment are not described, for example, because they are assumed to be the same as in the case of phasing out pesticides. The consequences of different livestock housing systems for the working environment in the organic scenarios (see section 5.3) are not described.

Sections 6.1 and 6.2, in which production-related pollution and energy consumption are discussed, are based directly on the organic scenarios described in chapter 5. The other sections – 6.3 on nature content, 6.4 on soil biology, 6.5 on consequences of constituents and 6.6 on veterinary drug consumption – are less closely related to the scenarios and are based on a number of Danish and international studies of organic farming and organic products.

6.1 Losses and pollution with nitrogen and phosphorus

Pollution with nutrients is assessed on the basis of the potential for losses

– taking AEP II into account

In this section, the pollution with nutrients in a 100% organic agricultural sector is assessed by describing the potential for loss of nitrogen and phosphorus in the organic scenarios as described in chapter 5. Danish agriculture as it was in 1995/96 is compared with how present agriculture is expected to be with full observance of Aquatic Environment Plan II (AEP II). In this last scenario, the livestock population is assumed to be as in 1995/96, while the growth of organic farming is assumed to continue, with an additional 210,000 hectares restructured in the period 1996-2003, besides the 45,000 hectares restructured in 1996. Other measures in the scenario are set-aside of wetlands and "particularly sensitive rural areas", afforestation, increased use of second crops, reduced use of the nitrogen standard and stricter requirements concerning use of feed and use of manure. It is estimated that these measures will together reduce the yield in all crops by more than 7%, or more than 1,200 million f.u. (Grant 1998). For comparison, the corresponding reduction in yields in the organic scenarios is 20-31%.

6.1.1 Nitrogen

Nitrogen lost

The overall nitrogen balance for the agricultural sector is based on estimates of supplied and removed nitrogen, as described and discussed in section 5.7. Loss of nitrogen to the atmosphere and the aquatic environment, which is not included in the overall balance, is described here. There is a risk of nitrogen loss in different places in the agricultural system's feed and nutrient cycle. The environmental impacts of nitrogen relate particularly to evaporation of ammonia and leaching, but denitrification in the soil and, secondarily, in the aquatic environment, can also result in emission of the greenhouse gas N₂O (see section 6.2).

- including through evaporation of ammonia

Balance – ammonia evaporation = net to soil.

The loss in the form of ammonia evaporating from manure depends on the production system and decreases with decreasing livestock production. However, in AEP II, better utilisation of feed is expected to reduce the amount of ammonia evaporating from manure. This change is not taken into account in the organic scenarios. There is also evaporation of ammonia from crops; this is assumed to be the same in all scenarios. 1995/96 and AEP II also include evaporation from artificial fertiliser and ammonia treatment of lye. The total balance for supply and loss of nitrogen in farming, minus the estimated loss in the form of evaporation of ammonia, gives a figure for the net supply of nitrogen to the soil (table 6.1). It should be noted, however, that the calculations are encumbered with great uncertainty, particularly concerning nitrogen fixation, as mentioned in section 5.7.1.

Net to soil = leaching + denitrifcation + changes in soil pool

All else being equal, the total balance for N to soil gives an indication of the potential for nitrogen leaching and denitification in the soil. This potential must be compared with the possibility of accumulation or release of organically bound nitrogen in the soil. Changes in the soil pool's content of N depend, at any rate in the short term, on cultivation practice. For example, a bigger proportion of perennial clover in the rotation has a beneficial effect on the soil's nitrogen pool, whereas frequent and intensive soil preparation has an adverse effect (Christensen & Johnston 1997). Readers are referred to Christensen et al. (1996) for a more detailed discussion of the effect of cultivation on the decomposition of organic matter in the soil in relation to organic farming.

However, with constant use of the same cultivation practice, it can be assumed that, in the long term, the soil's nitrogen pool will be constant because the mineralisation from the soil pool is assumed to be proportional to the size of the soil pool (Christensen & Johnston 1997). Thus, with constant cultivation practice, the size of the soil pool will gradually reach a point at which there is balance between supply and loss.

Relatively little denitrification

Denitrification is a process in which, in anoxic conditions, bacteria convert nitrate into gaseous nitrogen compounds. In connection with AEP II, denitrification in wet meadowland is used as a means of reducing nitrogen leaching to the aquatic environment. Reestablishment of 16,000 hectares of wet meadowland, where there is considerable denitrification, is expected to result in the removal of 5.6 million kg nitrogen (Iversen et al. 1998). With normal cultivation practice on land under rotation, denitrification depends in part on the type of soil and the water content of the soil. A clear relationship with cultivation practice has not been established, but it is assumed that denitrification is associated particularly with the use of manure and that, in normal circumstances, the quantities lost are relatively small (Petersen 1996).

Net to soil is a potential for leaching
- which is reduced by 50-70%

Assuming equilibrium with the given cultivation practice in farming today and in the organic scenarios, so that the soil's nitrogen pool is constant, the reduction in the net supply of nitrogen to soil can be taken as a reduction of the potential for nitrogen leaching. It will be seen from table 6.1 that the net supply of nitrogen to the soil is reduced by 112 million kg under AEP II compared with Danish agriculture 1995/96, while the reduction is between 164 and 241 (+/-56) million kg per year in the six organic scenarios compared with Danish agriculture 1995/96. The interval indicates an uncertainty in the estimate for nitrogen fixation, which is the item associated with greatest uncertainty. For this reason, in the long term, a considerable reduction in leaching of nitrogen must be expected in the organic scenarios compared with Danish agriculture today. It should be noted, however, that the calculations are encumbered with great uncertainty.

- and a considerable reduction of leaching is expected.

Table 6.1
Overall nitrogen balance for the agricultural sector (mill. kg per year), together with the net supply to the soil and the reduction of this compared with Danish agriculture 1995/96

	Danish agri- culture 1995/ 96	APAE II	Organic scenarios^a
			Present level of yield			Improved level of yield
			0% im- port	15- 25%	Un- limited	0% im- port	15- 25%	Un- limited
N- balance	418	305	146	209	245	167	229	238
Ammonia loss	76	69	45	57	67	50	65	67
N to soil (mill. kg)	342	236	101	152	178	117	164	171
Reduction in N to soil (mill. kg)	–	112^b	241	190	164	225	178	171
Reduction in N to soil (mill. kg)	–	112^b	+/-53^c	+/-53	+/- 53	+/-57	+/-57	+/- 57
N to soil (kg/ha)	126	87	37	56	65	43	60	63

^{a The expected effects of AEP II are not included in the
organic scenarios.
^{b Incl. reduction of 5.6 mill. kg as a consequence of
increased denitrification
^{c This interval gives an uncertainty on the estimate for
nitrogen fixation in clover grass (see section 5.7 for details)
Free-range sows can cause problems
Grazing is far more extensive in the organic scenarios than in present-day
agriculture, and the fields would thus receive about three times as much manure as they do
today. This would cause problems for the environment, particularly in connection with
free-range sows, because sows like rooting in the soil and thereby break the grass cover.
To reduce the risk of leaching of nutrients, it would be necessary to maintain close grass
cover. Rooting could be reduced by ringing the sows. In organic farming, it is recommended
that the sows be allowed to graze and that the use intensity be reduced in relation to the
minimum area of 0.074 hectares per sow. This can be done by establishing buffer pens, pen
rotation or grazing with other livestock. It is also recommended that the sows be supplied
with greenfeed or other filling root material according to their appetite in periods with
reduced grass growth (Larsen et al. 1998).
- and the potential for leaching is uncertain in the short term
With our present-day level of knowledge it is not possible to say anything clear
about the potential for leaching in the short term as a consequence of the changed
cultivation practice with a total switch to organic farming except that there would be a
big incentive to take best possible care of the limited quantity of nitrogen. Assuming a
yield response of 12 kg cereal per kg total N supplied (Askegaard and Eriksen, 1998) and
DKK 1.5 per kg cereal, it can be calculated that the value of one kilo of nitrogen is DKK
18, which is 5-6 times higher than in conventional farming today. A detailed discussion of
the potential for nitrogen leaching in the short term in connection with conversion to
different types of organic farming is to be found in Kristensen & Olesen (1998).
6.1.2 Phosphorus

The environmental effects of phosphorous

- depend particularly on the phosphorus content of the soil
The phosphorus balance is less complex than the nitrogen balance because phosphorus
is neither fixated from nor lost to the atmosphere. In modern agriculture, the undesirable
environmental impacts of phosphorus are associated particularly with loss to the aquatic
environment via soil erosion and transport of phosphorus down through the soil profile.
These environmental impacts depend less on the supply in individual years than on the
soil's total content of phosphorus.
When phosphorus is supplied to the soil with fertiliser or manure, the soluble part
dissolves in the soil water, reacts with the soil's adsorption complex and consequently
participates in an equilibrium process with the soil's less soluble forms of
adsorption/precipitation of phosphorus. That means that phosphorus supplied with
fertiliser/manure is immobilised. Phosphorus in the organic fraction of the fertiliser
must undergo mineralisation before it can participate in the equilibrium process.
Conversely, when crops absorb phosphorus from the soil water or if phosphorus leaches from
the soil water, a reaction takes place from less soluble to more soluble forms, i.e. the
phosphorus is mobilised. The crops normally absorb less than 10% of the fertiliser
supplied in the individual year; the remainder comes from the soil pool.
The losses are small

- but can cause eutrophication
Loss of phosphorus to the aquatic environment through leaching usually accounts for
only a small part of the net supply of phosphorus; the rest accumulates in the soil.
Measurements carried out under AEP II's monitoring programme thus show average transports
of 0.35 kg P/hectare/year in watercourses from farming-dominated catchment areas for the
period 1989/95, which corresponds to a loss of just under 1 mill. kg P per year from the
entire agricultural area. These figures can be compared with the balances in table 6.2.
Although the loss of phosphorus to watercourses is of less agronomic importance, it is so
high that it can cause eutrophication in shallow lakes and fiords.
When the soil's phosphorus content rises far above the agronomically optimum level,
presumably at Pt of around 6, the risk of leaching of P increases drastically. Approx. 15%
of Danish farmland has Pt above 6.0 (Grant 1998). The phosphorus balance in the organic
scenarios is generally lower than in Danish agriculture 1995/96, even allowing for the
lower feed standards since 1996 (section 6.2). In the longer term, a negative phosphorus
balance in land with a very high phosphorus content can reduce the content of phosphorus
and thus also the risk of leaching.
Table 6.2

Phosphorus balances for agriculture, nationally and as an average per hectare agricultural
land, per year (Grant 1998)

Danish
agri- culture 1995/ 96^a
Organic
scenarios

Present
level of yield
Improved
level of yield

0% im- port
15- 25%
Un- limited
0% im- port
15- 25%
Un- limited

P-balance (mill. kg)
36.8
-4.0
11.5
23.2
-2.3
15.6
18.5

P-balance (kg/ha)
13.5
-1.5
4.2
8.5
-0.9
5.7
6.8

^{a Reduced by 3.3 mill. kg in accordance with changed feed
standards for phosphorus for cattle since 1996.
The mobility of phosphorus also depends on the form of fertiliser and on the
cultivation in practice. For example, in English soils, Johnston (1998) found that the
mobility was greater when the fertiliser was supplied as organic fertiliser than when it
was in the form of artificial fertiliser and that phosphorus was transported deeper into
the soil under permanent grass than in rotation. This indicates that the mobility of
phosphorus increases in the presence of fresh organic matter from supplied natural
fertiliser or metabolism under permanent grass. However, there are no research results
that provide a quantitative description of the risk of loss of phosphorus as a consequence
of changed cultivation practice (Grant 1998).
6.2
Consumption of fossil energy and production of greenhouse gases

Consumption of fossil energy results in emission of the greenhouse gas CO₂
In this section we assess the consequences of a 100% switch to organic
farming for agriculture's consumption of fossil energy – both direct consumption in
Danish agriculture and indirect consumption in the production of fertilisers etc. –
and for greenhouse gas emissions. Besides "classic" pollution with sulphur,
nitrogen compounds, etc., the environmental consequences of fossil energy consumption are
increased emission of carbon dioxide (CO₂), which acts directly as a greenhouse
gas in the atmosphere. Other important greenhouse gases that are closely associated with
biological processes in agriculture are methane (CH₄) and nitrous oxide (N₂O).
More qualitatively, we will discuss the effects of changes in land use and livestock
population on the emission of methane and nitrous oxide. Measured in terms of direct
energy consumption per krone of turnover, the agricultural sector is the second-most
energy-intensive industry. The most energy-intensive is the transport sector. In all,
agriculture contributes around one tenth of Denmark's total contribution to the man-made
increase in the greenhouse effect (Dalgaard et al., 1998).

6.2.1 Consumption of fossil energy

The consumption is the sum of the direct and indirect consumption
The agricultural sector's consumption of fossil fuel is calculated as the sum of
the energy consumption for production of crops and animal products, and the energy
consumption for the individual crops and products is the sum of the direct consumption of
fuels and electricity and the indirect energy consumption via artificial fertiliser,
machines, buildings and imported feed.
The direct energy consumption can be calculated and estimated with great certainty, but
it is more difficult to calculate the indirect consumption. The cost of energy via
imported feed, which is a big item, both in present-day agriculture and in the organic
scenarios with imports, thus depends on the type of crop, the cultivation method, etc. We
have chosen to use one and the same energy cost for all imported feed (Dalgaard et al.
1998). For present-day agriculture, energy for production of artificial fertiliser
accounts for a significant part of the indirect energy consumption.
Net energy consumption = energy for plant production + energy for livestock
production – energy production from biofuels
Table 6.3 shows the total net energy consumption in present-day agriculture and in
the organic scenarios, compared with the size of the plant and livestock production. The
total energy consumption is the sum of the energy consumption for crop production plus the
extra energy consumption for livestock production, less the direct energy production from
burning of straw and biogas.
Table 6.3

Agriculture’s consumption of fossil energy, compared with crop and livestock
production (Dalgaard et al., 1998)

Danish
agri- culture 1996

Organic scenarios

Present
level of yield
Improved
level of yield

0% im- port
15- 25%
Un- limited
0% im- port
15- 25%
Un- limited

Crop prod. (bill. f.u.)
15.9
11.0
11.4
11.6
12.3
12.8
12.9

Crop prod. (PJ ME)^a
199
138
143
145
154
160
161

Livestock (mill. l.u.)
2.3
1.7
2.1
2.4
1.9
2.3
2.4

Energy for crop production (PJ)
37
17
17
17
17
17
17

Energy for livestock production (PJ)
41
13
29
41
14
31
37

Energy consumption, total (PJ)
78
30
46
58
31
49
54

Energy production (PJ)
14^b
0
0
0
0
0
0

Net consumption (PJ)
64
30
46
58
31
49
54

^{a Converted from feed units into metabolised energy with
the factor 1 f.u. = 12.5 MJ ME.
^{b There is a potential for further energy production in
present-day agriculture, corresponding to the burning of the grain exported in 1996 (2
bill. kg * 15 MJ/kg = 30 PJ). Utilisation of this potential would have derivative
socioeconomic consequences.
These calculations show that a switch to organic production could mean a reduction of 9
to 53% in net energy consumption, depending on the size of feed import and thus on the
size of livestock production.
Energy can be defined in different ways
Energy consumption must be compared with the differences in production, as also
shown in table 6.3. There is thus 20-30% less plant production in the organic scenarios
compared with agriculture today. It is difficult to set up a complete energy balance for
agriculture in which the energy in the different inputs and products are summed because
energy cannot be precisely defined. For example, the energy in one kilo of clover used as
cattle feed is not the same as if used for pigs or humans, and the calorific value is in
turn different from the metabolic energy. However, generally speaking, there is a net
production of energy in arable farming, whereas energy is consumed in livestock
production.
while energy consumption per feed unit is lower in the organic scenarios
Figure 6.1 shows the energy production from biofuel and the metabolic energy in
plant production in Danish agriculture in 1996 and in the two scenarios with the same
livestock population, compared with the energy consumption for crop production. It will be
seen that more energy is produced net in conventional arable farming. However, energy
consumption per feed unit is considerably smaller in the organic scenarios than in
present-day agriculture (see table 6.4). That is due in part to a different crop
composition, in that it takes considerably less energy to produce feed units in clover
grass than in, for example, cereals. However, also within the individual crops, energy
consumption per feed unit is lower in organic production, mainly because industrially
produced nitrogenous fertilisers are not used.
Conventional arable farming produces most energy
Figure 6.1

Comparison of energy production (PJ biofuel and PMJ metabolic energy) and energy
consumption (PJ) in plant production in 1996 and in the two organic scenarios with the
same livestock production (unlimited import)

(Figure text)

Danish agriculture

1996
Present yield level
Improved yield level

Organic farming
Unlimited import

(Box text)

Energy production, biofuel (PJ)

Metabolic energy in plant production (PJ ME)

Energy consumption for plant production (PJ)

- just as energy consumption per livestock unit is lower
Total energy consumption per livestock unit, including energy for feed, is smaller
in the organic scenarios than in present-day agriculture (table 6.4). In the scenarios in
which the livestock production is maintained, that is mainly due to the smaller energy
consumption in the domestic production of feed, but also to the fact that fossil energy is
not used for heating in organic pig farming. In the other scenarios, the changed
composition of livestock production also plays a role because, in pig farming, the energy
consumption per livestock unit is approximately twice as big as in dairy farming (Dalgaard
et al. 1998).
Table 6.4

Energy consumption per produced feed unit and total energy consumption per livestock unit (Dalgaard
et al. 1998)

Danish
agri- culture 1996

Organic scenarios

Present
level of yield
Improved
level of yield

0% im- port
15- 25%
Un- limited
0% im- port
15- 25%
Un- limited

Energy consumption per feed unit (MJ/f.u.)
2.4
1.4
1.4
1.4
1.3
1.3
1.3

Energy consumption per livestock unit
(MJ/l.u.)
31
17
22
24
18
21
22

Organic arable farming is more energy-efficient, while conventional arable farming
produces most energy per hectare
In an analysis of energy consumption in agriculture, it is important to be aware
that arable farming, seen in isolation, produces a big energy surplus and that some plant
products can be used for energy purposes. For example, cereals for burning contain much
more energy than is consumed in their production. That applies in both conventional and
organic farming. Organic production is more energy-efficient per kg cereal produced, while
conventional farming produces most net energy owing to a larger yield. The energy content
of the 2 billion kg cereal that was exported in 1996 (see table 5.3) corresponds to a
gross calorific value of 30 PJ (Dalgaard et al. 1998). Burning instead of export would
have derivative socioeconomic consequences.
Straw can be used as a fuel
In present-day agriculture (excluding rape, seed grass and peas) there is a surplus
of straw amounting to about 1.8 billion kg, which is ploughed in. That is over and above
the quantity of straw already used for energy purposes today. In the organic scenarios,
straw is not used for energy purposes, although there is some surplus that could be used
to maintain some of the present energy production from straw. In present-day agriculture
there is a potential for increased use of straw for energy purposes, and one of the
objectives of the government's biomass action plan is to increase that use of straw.
Table 6.5

Straw production and straw consumption for feed and bedding in agriculture in 1996 and in
the organic scenarios (billion kg) (Alrøe et al. 1998a, Agricultural Advisory
Service, personal communication)

Danish
agri- culture 1996

Organic scenarios

Present
level of yield
Improved
level of yield

0% im- port
15- 25%
Un- limited
0% im- port
15- 25%
Un- limited

Straw production^a
5.5
2.2
2.6
2.8
3.6
4.0
4.0

Straw for feed
1.9
0.4
0.4
0.5
0.3
0.4
0.4

Straw for bedding
0.8
1.0
1.5
1.8
1.2
1.7
1.8

Straw for energy purposes
1.0
0
0
0
0
0
0

Surplus straw
1.8
0.8
0.8
0.5
1.2
1.0
1.0

^{a Excl. rape and seed grass. Straw production in the
organic scenarios is calculated in relation to present straw production, using a factor of
0.58 (=5.5 bill. kg straw/ 9.5 bill. f.u. cereal) times the yield in cereals and mixed
seed.
- but many other factors have to be considered
Many other factors have to be considered concerning cultivation of agricultural
crops for energy purposes, including the possibility of growing real energy crops and
afforestation. A detailed discussion of biomass for energy in relation to organic farming
is given in Christensen et al. (1996). The organic scenarios analysed in this report have
not been designed for energy purposes. To clarify the role of agriculture as an energy
producer it would be necessary to analyse conventional and organic scenarios that have
energy production as one of their objectives.
6.2.2 Greenhouse gases
The simulated energy consumption has been converted into CO₂emission and
compared with the agricultural sector’s emissions of CH₄ and N₂O
(table 6.6). It will be seen that these two greenhouse gases are of considerably greater
importance than CO₂. In the following we differentiate between domestic and
foreign emission in the economic valuation (see section 7.4), with only the domestic
emission valued in accordance with current international agreements in this area.
Domestic emission

- falls by 8-24%
The calculated fall in the agricultural sector’s energy consumption would mean
a corresponding fall in domestic CO₂ emission in some of the organic scenarios.
The emissions of CH₄ and N₂O would also fall in some of the organic
scenarios. However, it should be noted that these estimates are encumbered with great
uncertainty, particularly in connection with the transition to a different form of
production, such as organic farming. The difference in the emission of N₂O is
due particularly to the size of the nitrogen turnover (see table 5.11). The emission of CH₄
is closely linked to the number of livestock, with ruminants as the biggest source. All in
all, the calculated fall in domestic emission of greenhouse gases is 8 to 24% in the
organic scenarios, measured in CO₂ equivalents (table 6.6) (Dalgaard et al.
1998).
Table 6.6.

Domestic and foreign emission of greenhouse gases in CO₂ equivalents per year
(bill. kg) (according to Dalgaard et al. 1998)

Danish
Agri- culture 1996

Organic scenarios

Present
level of yield
Improved
level of yield

0% im- port
15- 25%
Un- limited
0% im- port
15- 25%
Un- limited

Domestic CO₂
2.5^a
2.0
2.2
2.6
1.7
2.0
2.1

CH₄
6.7
5.6
6.1
6.5
6.0
6.6
6.7

N₂O
4.0
2.4
2.8
3.1
2.5
2.9
3.0

Domestic, total
13.2
10.0
11.1
12.2
10.2
11.5
11.8

Fertiliser etc.
0.9
0.2
0.2
0.2
0.2
0.2
0.2

Import of feed
1.5^b
0
1.0
1.9
0
1.1
1.5

Foreign CO₂, total
2.4
0.2
1.3
2.1
0.2
1.4
1.8

Total emission
15.6
10.3
12.4
14.3
10.4
12.9
13.6

^{a The cost of producing the approx. 2 bill. kg grain
exported in 1996 corresponds to 0.4 bill. kg CO₂.
^{b If the grain export is offset against the feed import on
the assumption that the exported grain can substitute imported feed, the fall in feed
import corresponds to a fall of 0.9 bill. kg CO₂(exported grain / imported
feed * 1.5 bill. kg CO₂).
- and the foreign emission falls sharply with import of feed
In the global CO₂ account, the emission of CO₂in other
countries that is connected with Danish agricultural production also counts. Table 6.6
shows the breakdown of the foreign emission of CO₂ between production of
fertiliser and machines and import of feed. It will be seen that there is less foreign
emission in the organic scenarios and that a smaller livestock population as a consequence
of a smaller import of feed results in less CO₂ emission in other countries in
the organic scenarios. This raises the question of whether a switch to organic farming in
Denmark would result in increased production in other countries, which would reduce the
effect on the global CO₂ account. The feed import in Danish agriculture 1996
could to some extent be substituted by the grain that is exported, which would reduce by
up to 0.9 bill. kg the CO₂ emission in other countries that is connected with
the production of the imported feed. Alternatively, with increased use of crops for energy
purposes, a considerable saving could be achieved in the net energy consumption in Danish
agriculture and thus a fall in the domestic emission of CO₂ – to the
extent that this energy production substitutes fossil fuel. The fall in CO₂
emission with use of the cereal that is at present exported for energy production thus
corresponds to approximately the present domestic CO₂ emission of 2.5 bill. kg
(table 6.6).
Alternative use of cereal export would have a significant effect on these
calculations
6.3 Nature content
– effect on fauna and flora
In this section we summarise the consequences of total switch to organic farming for
flora and fauna in both cultivated and uncultivated land in the Danish rural landscape.
Natural content affected dif-ferently in the different types of biotope
To describe the natural status and relations it is necessary to look at the
country, the regions and the farms etc. as a unit from the point of landscape ecology. At
the same time, it is important to separate the main types of biotope in the agricultural
landscape when evaluating the natural potential of restructuring for organic agriculture.
These main types of biotope are fields in rotation, semi-natural ecosystems and both these
types of biotope’s immediate neighbours, the small biotopes. Because of their small
size and shape, the small biotopes are normally characterised by a high edge: area ratio,
which makes them particularly sensitive to impacts from production in neighbouring areas
(Reddersen 1998).

6.3.1 Set-aside acreage

The density of individuals would increase relatively rapidly in fields in rotation
In acreage in rotation, quantitative changes – an increase in the
density of individuals – would occur relatively rapidly after conversion (within one
to a few years). This applies to both weed flora and insect fauna. The total densities of
individuals would then presumably "stabilise" at a new, higher level. The other
higher fauna, vertebrate fauna, are only rather peripherally or periodically attached to
fields in rotation and would therefore react less, less certainly and less quickly.
However, some field specialists could also react positively and relatively quickly
(Reddersen 1998).
and, in the slightly longer term, the species diversity would also increase

- although most in the case of relatively common species
Owing to the generally big ability to spread in rotation-field species, qualitative
effects in the form of recolonisation and immigration of new species would also occur
immediately after conversion and would continue, gradually increasing in the short and
medium term, and then stabilise. The diversity of species of both flora and fauna would
thus very probably increase significantly in a fully organic scenario. However, a large
part of the increased diversity would consist of species that were already relatively
common. In this development, a few species within all groups of flora and fauna might
become less numerous – calculated as individual densities. Such species include
certain pests and pathogens such as aphids and mildew, but undoubtedly also certain
neutral species. However, they would not be of any great significance in the big picture.
The increase would be due mainly to the absence of pesticides
The complete discontinuation of the use of pesticides would play a vital
role in the increased density and species diversity – including some well-known pests
and pathogens. However, harmful insects and their frequency depend on other factors as
well, such as soil preparation, rotation, choice of variety and variety mixtures,
biological control and the biochemistry of the crop, which is affected by the supply of
nutrients. Without pesticides one would avoid the direct toxic effects – including,
particularly toxic effects on the main species, which are not harmful. At the same time,
one would avoid the often equally big, indirect, non-toxic effects, where organisms higher
up in the food chains are deprived of their basis for life in the form of food, shelter,
etc.
The above benefits from the absence of pesticides are deemed to be far greater than the
negative effects that can be caused by other forms of weed control. However, a few
sensitive organisms within all groups of flora and fauna would be harmed by mechanical
soil treatment, flame treatment and similar (Reddersen 1998).
- while it is more difficult to assess the changes in rotation
It is more difficult to assess the effects on the natural content of the changes in
the crop rotation. The species composition of sprouting weeds would depend on the
crop rotation and the individual crop, but, conversely, the seed bank could have a
strongly moderating effect. It is judged that the organic crop rotation would offer
conditions of life to several different types of weed – considered over the entire
crop rotation. A larger proportion of spring crops combined with more frequent
preservation of stubble fields over the winter is deemed to be of great importance for a
number of less common but mainly unproblematic species of weed and, at the same time, of
benefit to the real field bird species and birds spending the winter in Denmark. The
expected increased proportion of clover grass/lucerne crops would easily replace the lost
rape as important winter larder from some birds and mammals. The increased proportion of
perennial crops would be of great advantage to some field insects with a long life cycle
that spend the winter in the soil, including a few well-known harmful insects (Reddersen
1998).
6.3.2 Semi-natural
ecosystems and small biotopes
In small biotopes and semi-natural ecosystems

- the absence of pesticides

- reduction of fertilisation

- and no longer any centrifugal spreading of fertiliser play a role
Organic farming differs from conventional farming in two ways:

by ensuring against direct placing or drift of pesticides to both small biotopes
and semi-natural ecosystems. In these biotopes, well-preserved vegetation is essential for
the ecosystem. The plant species, in particular, are extremely sensitive to herbicides
– acutely because of high sensitivity and in the long term because of poor
possibilities for recolonisation as a consequence of a low dispensability and a small and
short-lived seed bank.
through a considerable reduction in the placing and drift of fertilisers to both
small biotopes and semi-natural ecosystems. Drift to edge biotopes would be effectively
reduced without centrifugal spreading of fertiliser. On the other hand, organic dairy
farmers also need to control local sources of ammonia deposition that can be deposited
along windbreaks. It can be assumed that the shortage of fertilisers would effectively
stop the placing of fertiliser in semi-natural ecosystems because other crops would be
prioritised.

and grazing would be important
With the extensive use of grazing in organic farming, it can be assumed that
semi-natural ecosystems would also be grazed, which would be necessary to ensure a light,
warm microclimate and avoid overgrowing.
- but there is great "organic inertia"
It is important to stress that very great "ecological inertia" must be
expected after earlier damage to the natural content of small biotopes and semi-natural
ecosystems, especially to the vegetation, because of maintained eutrophication in the
nutrient pool and slow recolonisation. Although organic farming could protect remaining
natural assets, one could only in the very long term expect any real nature restoration
effect on impoverished land. (Reddersen 1998)
6.3.3 Landscape in general

Considerable change in landscape ethic
In a 100% organic agricultural sector there would be a diversified crop rotation
and grazing animals all over the country. The landscape ethic would thus be very different
from Danish agriculture today, where production is far more specialised.
An example of the consequences of the expected changes in both crop-rotation acreage
and semi-natural ecosystems is the consequences for the number of birds. Braa et al.
(1988) thus found that among characteristic farmland birds there were 2-3 times as many
individuals on organic farms than on conventional farms. However, Reddersen (1998) finds
that this difference is not due to the absence of fertiliser and pesticides but, rather,
to the landscape’s mosaic (structural diversity). The significance for the fauna is
described further in the report from the Sub-committee on Environment and Health.
6.4 The biology of the soil
The biology of the soil is here defined as including those organisms that belong to the
soil’s metabolic food chain, i.e. microorganisms (bacteria and fungi), macrofauna
(protozoa, tardigrades and nematodes), mesofauna (cellemboles, mites and enchytrae),
together with macrofauna (earthworms). Insects that have one or more stages of life in the
soil or that live above the soil (e.g. species of flies, gnats and beetles) are not
included.
The soil’s organisms are of importance to the fertility and structure of the
soil

- and the food chain
Microorganisms play an important role for soil fertility and would be of critical
importance to a wide range of cultivation factors in organic farming. The metabolism of
the soil’s organic matter can primarily be attributed to microbial activity. The
microorganisms play a vital role in the structure of the soil and provide food for many of
the soil fauna. Springtails (collemboles) and mites increase the rate of liberation of
nitrogen etc. accessible to plants from the soil’s pool of organic matter by grazing
on the microflora, and they play a role as prey for predators in the springtime, when
other sources of food are in short supply. Earthworms are of great importance to the
structure and fertility of the soil. They are the first link in the decomposition of plant
parts and play a major role in the physical structure of the soil by making passages that
affect the ability of the soil to suck up water and lead it away.
Effect of restructuring

- depends on the type of farm
The quantity of organisms in the soil depends on a wide range of factors – for
example, the type of soil, type of fertiliser, crop rotation, soil preparation, climate,
season, etc., and it is therefore extremely difficult to determine what is the effect of
organic production in itself and what is due to other factors. Only in the case of
microorganisms are there sufficiently comprehensive studies to provide good estimates of
effects across all these factors. These studies have been included to some extent, but it
should be noted that they have not been fully processed statistically. For the other
groups we have mainly assessed the effect of restructuring by assessing the effect of
changes in crop rotations. This means that the biological consequences of converting to
organic production would depend very much on the type of farm that was there already.
Converting from conventional production with a balanced livestock population and mainly
use of manure for organic production would not result in such big changes in the
biological conditions as converting from conventional arable farming without the use of
manure and with what is usually a one-sided crop rotation.
A considerable increase is expected
The effects of restructuring have been calculated by summing the effects of
restructuring from different types of farm in present-day agriculture to 100% organic
farming with a crop rotation as described in chapter 5, taking into account the
distribution of the types of farm with respect to types of soil. The total estimates of
the effect of restructuring must be regarded as rough estimates because a wide range of
sources of variation have not been taken into account here. For the country as a whole it
is estimated that the microbial biomass would increase by 77%, the density of collemboles
by 37%, and the density of earthworms by 154% (Axelsen & Elmholt 1998).
- mainly as a consequence of changed crop rotations
It would thus be possible to considerably increase life in the soil by converting
to organic production. In the calculation of the effect on collemboles and earthworms,
account has only been taken of changed crop rotations. In other words, any effects of the
organic form of production besides crop rotation and type of fertilisation, including the
effect of using pesticides, would increase the effect of restructuring. Besides the
crop-rotation effect, there would probably also be an effect on microbial biomass and
earthworms, since scientific studies point in that direction. An effect of organic
production on the microbial biomass should also penetrate to the mesofauna (collemboles,
mites and enchytrae) or to parts of the mesofauna, since many species from this group of
fauna live on microorganisms. There are just no studies to confirm or disprove that
(Axelsen & Elmholt).
6.5 Health consequences of plant
products

There is not a sharp dividing line between organic and conventional production

- and different perceptions of health
In this section we shall look at possible health consequences of differences
between the organic and the conventional form of cultivation. However, it is not possible
to differentiate sharply between organic and conventional production because, in some
respects, some forms of conventional production do not differ significantly from the
corresponding organic production. On the other hand, the organic perception of health
differs considerably from the analytical approach used here to look at the health
consequences, with the focus on the content and effect of the various physiologically
important substances. Seen from the point of view of the original organic movement, the
health concept covers the entire relationship between diet, farming and environment, and
changes in diet are closely connected with how the food is produced, which is reflected in
the consumers’ preferences (Kølster et al. 1996).
A health difference has not been proven

- our knowledge is limited
There are no published studies that show definitively whether there is a health
difference between plant products from organic and conventional production. A qualitative
review has therefore been carried out of the known knowledge concerning the importance of
cultivation factors to the content of physiologically important substances, including the
so-called secondary metabolites, and an assessment is given here of whether, on the basis
of that knowledge, we can expect differences of an order of magnitude that would be of
importance to health. Here, it is a problem that our knowledge about the importance of the
individual substance to health is in many cases limited, partly because the importance of
some substances has not been fully clarified, partly because most of the substances that
have been thoroughly studied, e.g. vitamins, are only beneficial if there is otherwise too
little of them in the diet and partly because it is not possible to divide natural
components into health-promoting and harmful substances; most of the possibly
health-promoting components also have certain toxic effects in themselves, and,
paradoxically, these may be a condition for their health-promoting effects (Veterinary and
Food Directorate 1999).
- and health-promoting substances are often also toxic
The cultivation conditions that are known to be of direct and indirect importance
to the content of physiologically important substances including the supply of nitrogen,
the type of fertiliser and the use of pesticides.
A possible effect of restructuring for organic production
When considering the importance of the entire form of cultivation, across crops and
products and on the basis of the available knowledge, the main question is whether
differences in the form of cultivation can generally be expected to result in a
significant difference in the population’s intake of groups of substances that
are generally regarded as beneficial or harmful. That gives a qualitative assessment of
the possibility of a health benefit or the reverse with switching to organic production,
but with our present level of knowledge, it is not possible to say anything about the
magnitude of a possible effect (Brandt el al. 1998).
- depends on the content of substances and intake of the food product
If there proves to be a difference in the concentration of physiologically
important substances in a food product, the effect on the population’s intake of a
substance with restructuring for 100% organic production would be the product of changes
in the content of substances and changes in the intake of the food product, with the
latter in turn depending on the price relationship. For a final assessment of the health
consequences for the population and domestic animals, it is therefore also necessary to
take food and feed prices and consumer preferences into account.
The differences are generally small compared with other changes in the diet
The general conclusion is that 100% organic production can be expected to result in
a number of changes in the content of substances that are important to human and animal
health. Some substances can have a beneficial effect on health, and others an adverse
effect. However, the differences are generally small – they are expected to be far
smaller than the effect of the cultural changes in the composition of the diet that have
taken place in the last 50 years (Brand et al. 1998).
6.6 Consumption of veterinary drugs

Different types of veterinary drugs are used

- with most use of growth promoters
A number of veterinary drugs are frequently used in Danish agriculture. Besides the
therapeutic treatment of diseases, a number of substances are also used as growth
promoters. Growth promoters are usually antibiotics, but they can also be compounds of
copper or zinc. They are given regularly to the individual animals in their feed or
drinking water, primarily in order to affect the bacterial flora in the gastrointestinal
tract, so that the animals grow faster and make better use of their feed. The consumption
of prescription drugs and antibiotic growth promoters for domestic animals in 1996 is
shown in table 6.7, broken down into groups, with an indication of the most commonly used
preparation in each group. As will be seen from the table, the consumption of antibiotics
as growth promoters at that time was almost twice the consumption of antibiotics for
treatment of diseases in domestic animals.
The use of growth promoters ends
Restructuring for organic production would result in a considerable reduction of
the consumption of antimicrobial substances in livestock production. The main reason for
the reduction would be an end to the use of antibiotic growth promoters, which, in 1997,
accounted for more than half of the consumption of antimicrobial substances in livestock
production. The consumption of antibiotic growth promoters is expected to be phased out in
1999 on the basis of voluntary schemes agreed within the various branches of Danish
agriculture.
Table 6.7

Consumption of prescription drugs, antibiotic growth promoters and antiparasitic products
for livestock (kg active ingredient per year), and a breakdown of the consumption into
types of animals (Bennedsgaard et al. 1998)

Type of veterinary drug Scope
Total con- sumption in 1996
Breakdown into types of animals

Hormone treatment
27
Mostly for dogs and cats

Central nervous system
237

Digestion and metabolism
1,456

Antibiotics (in feed)
1,706
Aquaculture (80%), poultry (20%)

Antibiotics (growth promoters)
105,548
Pigs (>95%)

Antibiotics (veterinary drugs)
48,676
Pigs (65-70%), cattle (25%)

Coccidiostatics (antiparasitic)
13,600
Broilers

Other antiparasitic products
?
Cattle and pigs

^{a A prescription is not required for antiparasitic products
and there are no official figures for the consumption.
- the consumption of therapeutic antibiotics would fall by about 30%
It is estimated that the consumption of therapeutic antibiotics would also fall in
the event of a switch to organic production. Changes in the consumption per animal are
shown in table 6.8. In all, it is estimated that consumption would fall by about 30% if
livestock production were maintained at the present level and by more with a smaller pig
production. An estimate of the total consumption after restructuring, with pig production
halved, is shown in table 6.8 (Bennedsgaard et al. 1998).
However, the estimate is very uncertain, due in part to limited experience with organic
production of fatteners. Extended retention time in connection with treatment and
restrictions on the access of owners to treat sick animals themselves are expected to lead
to a changed treatment pattern that will result in a lower consumption of antibiotics. A
lower level of yield in milk production, free-range bullock production and free-range pigs
are also expected to reduce the occurrence of infectious diseases.
Table 6.8

Change in consumption of antibiotics per animal with restructuring for organic production
and estimate of the total consumption with pig production halved (kg active ingredient per
year) (Bennedsgaard et al. 1998)

Production
Consumption per animal as % of
present consumption
Total consumption with pig
production halved

Dairy cows
75-85%

Calves
75%

Bullocks
Not known
10,000

Sows and piglets
40%

Fatteners
70-80%
8,000-12,000

Egg layers
No consumption

Broilers
No consumption

Other (sheep, goats, mink, hobby
animals)
Unchanged
3,500

- and consumption of antiparasitic products is also expected to fall
Consumption of antiparasitic products for pigs is expected to fall in step with pig
production. Consumption for cattle would fall because preventive treatment would no longer
be used, but it is not possible to estimate the size of the reduction owing to lack of
knowledge concerning the present use and uncertainty about the consumption of
antiparasitic products in connection with the transition to fattener production
(Bennedsgaard et al. 1998).
Effect on the environment insufficiently clarified
but it is assumed that discontinuing the use of growth promoters will reduce the
development of resistance
The effect on the environment of residual concentrations of veterinary drugs is
generally insufficiently clarified. However, effects have been detected on the insect
fauna and the decomposition of cowpats from use of the antiparasitic product Ivermectine
and on microbiological processes in compost and biogas as a consequence of the use of
growth promoters. It has been found that discontinuing the use of antibiotic growth
promoters results in less resistance development both in pathogenic bacteria and
environmental bacteria and, to a lesser extent, a reduction in the occurrence of resistant
bacteria. It must thus be assumed that discontinuing the use of growth promoters will
reduce the occurrence of antibiotic-resistant bacteria in livestock, including bacteria
that are pathogenic to humans, and reduce the risk of resistant genes being transferred to
bacteria that are pathogenic to humans. However, there are no studies that quantify the
occurrence and importance of this in relation to direct development of resistance in
connection with antibiotic treatment of humans. Increased outdoor production of pigs and
poultry in connection with restructuring for organic production could possibly result in a
slightly increased risk of certain diseases spreading from animals to humans (zoonoses)
(Bennedsgaard et al. 1998).
6.7 Summary and conclusion
A number of environmental consequences of a total switch to organic farming in Denmark
can be documented, although knowledge is lacking in many areas.
The consequences of a phase-out of pesticides are described in the report from the
Sub-committee on Environment and Health. This chapter should be seen as a supplement to
that report since we have tried to describe the possible further consequences of a changed
crop rotation and phasing-out of fertilisers.
Supply of nitrogen to the soil reduced by 50-70%
The calculations showed a 50-70% reduction of the net contribution of nitrogen to the
soil in the organic scenarios compared with Danish agriculture in 1996. Against this
background, we would have to expect a significant reduction of nitrogen leaching in the
long term, retaining the same cultivation practices. It should, however, be noted that the
calculations are encumbered with great uncertainty.
- and energy consumption reduced in step with production
The consumption of fossil energy and production of greenhouse gases would drop in step
with the scale of livestock production. In addition, energy consumption per unit produced
in both plant and livestock production would fall, mainly because of the changed
composition of crops and because manufactured nitrogen fertilisers would not be used. On
the other hand, if some of the crops were used for energy purposes, there would be a
bigger net energy production in conventional arable farming because of the higher yield.
The quantity and diversity of the flora and fauna would increase

- but there is great "ecological inertia"
A complete switch to organic farming would result in larger quantities of flora and
fauna in crop-rotation fields. Species diversity would gradually increase, although mainly
in species that are already rather common. The biggest qualitative effects would be found
in semi-natural ecosystems and in small biotopes because there would no longer be any
spreading and drift of pesticides or unintentional delivery of top-dressed artificial
fertiliser to edge biotopes. However, a very big ‘ecological inertia’ must be
expected after earlier damage to the natural content of small biotopes and semi-natural
ecosystems, especially to the vegetation, because of maintained eutrophication in the
nutrient pool and slow recolonisation. Although organic farming can be assumed to protect
remaining natural assets, one could only in the very long term expect any real nature
restoration effect on impoverished land.
The quantity of organisms in the soil increases considerably
A considerable increase in the quantity of organisms in the soil can be expected with a
switch to organic farming, mainly because of changed crop rotations. Microorganisms and
the soil fauna play an important role for soil fertility and would be of critical
importance to a wide range of cultivation factors in organic farming. The metabolism of
the soil’s organic matter can primarily be attributed to biological activity.
Microorganisms and earthworms play a vital role in the structure of the soil. The
subsoil's fauna play a role as food for predators above the ground.
Changes in the intake of physiologically important substances will be small
The consequences for public health of a total switch to organic farming would depend on
changes in the intake of physiologically important substances, which in turn would depend
partly on changes in the food products’ content of substances and partly on changes
in the population’s intake of different food products. Changes in consumption would
depend on various circumstances with and without connection with the conversion. A number
of changes can be expected in the content of physiologically important substances, but the
effect of these changes would be generally small compared with the effect of changes in
the composition of the diet.
Use of growth promoters will end

- and consumption of therapeutic pharmaceuticals will fall by 30%
Use of antibiotic growth promoters would end altogether with a total switch to
organic farming. It should be mentioned, however, that the use of growth promoters in
conventional farming is going to be phased out in 1999. Overall, it is estimated that the
consumption of therapeutic pharmaceuticals would fall by around 30% with unchanged
livestock production and further still with falling livestock production. Discontinuation
of the use of growth promoters is presumed to reduce the risk of transference of resistant
genes to bacteria pathogenic to humans.

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