The Sub-committee on Production, Economics and Employment has evaluated the total production figures in the optimised 0-scenario on the basis of the analysis in the economic model. With respect to production of sufficient feed units to maintain our present animal production, a production that would do this is planned at dairy farms in the 0-scenario. In the case of pig production, it is estimated that importing from other countries could make up for a reduction in cereal production. The economic consequences of such a change have been taken into account in the economic analyses.

Model for optimisation of crop rotations

Besides the purely agronomic crop rotations described in the foregoing, some types of farm have been set up on the basis of both agronomic and economic factors (see table 9.1 and appendix 1). Some agronomic restrictions have been set up, but it is largely the economic factors that have determined the crop composition. If a crop gives a large financial yield, the model increases the proportion of these crops in the crop rotation. If a crop is less profitable, it is omitted from the rotation. A pesticide ban would change the relative yield of the crops, cf. the losses set up by the Sub-committee on Agriculture. Some would be slightly changed, whereas others would be changed considerably. The consequences of a pesticide ban would thus in reality be a different crop rotation, and the changes would be caused by a mixture of agronomic and economic factors. The economic reactions have been modelled in an optimisation model (Ørum, 1998), which has to some extent been checked to determine whether the types of farm arrived at comply with the necessary agronomic restrictions. The economic analyses have been based on the Danish Institute of Agriculture and Fisheries Economics’ accounts statistics, which are expanded accounts statistics based on 2,000 farms, in which costs and prices are broken down between the 10 different types of farm. In the 0-scenario use has been made of the Sub-committee on Agriculture’s proposed substitutions, including, for example, mechanical instead of chemical weed control. Restrictions are imposed on the proportion of winter cereal and the crop sequence in the crop rotations.

Special crops omitted

Unlike the crop rotations proposed by the Sub-committee on Agriculture, in which the present proportions of special crops (sugar beet, seed and potatoes) are retained, with the existing price relations, these crops are almost totally phased out in the economic model. This accords well with the concerns expressed about these crops, in which the cost of weed control and losses – from potato blight, for example – is expected to be high. That means that other crops in a 0-scenario would outprice these crops.

Increased proportion of set-aside land

The substantial losses in many crops would impair the economy of farms to such an extent that set-aside would become advantageous. The proportion of set-aside acreage would rise (from 10% to 20-30%), particularly at pure arable farms, where the handling of liquid manure and harmonisation rules do not have to be considered. The scenario envisaged by the Sub-committee on Agriculture includes the same set-aside acreage as in present production practice. Whether such large set-aside acreages as those that are economically optimal would be allowed, politically, would depend on the effect this would have on production and economically in the agricultural sector.

The Sub-committee on Agriculture’s 0-scenario includes some rape and peas in several crop rotations. These crops have not been found competitive where farms are economically optimised, but have been replaced by rotation set-aside, which is also assigned a previous-crop value. Spring cereals also gain ground at the expense of winter cereals.

For a more detailed presentation of the different types of farm in the various scenarios, readers are referred to appendices 1 and 3.

10 optimised crop rotations

In the following we comment briefly on each of 10 types of farm described in a 0-scenario as a basis for evaluating whether the model’s propositions are realistic:

1. Arable farms on clayey soil: The proportion of set-side rises from 10 to approx. 30% and the proportion of spring barley from 19 to 41%. Wheat is reduced to 0 and, instead, the rye/triticale acreage is increased to approx. 30%. Spring barley and rye/triticale are increased considerably because they have lower loss functions than wheat in the 0-scenario. Rape and peas are not competitive.
2. Pig farms on clayey soil: Owing to the harmonisation rules, it will not be possible to have more than 10% set-aside. Oats and wheat are grown as the largest cereal crops due to the changed price relations because the cereal has to be grown for pigs, and also because the contribution margin in the base situation is more favourable to oats and wheat than to spring barley and rye. There is also a small production of peas and rape and a little winter barley.
3. Arable farms with beets on clayey soil: The set-aside acreage is increased to 30%; sugar beet is not grown at all because of the high cost of weed control. The cereal acreage consists only of spring barley because the beet producers traditionally get a higher settlement (about 10% higher) for barley that is used for malting.
4. Arable farms with seed production on clayey soil: Seed production is discontinued altogether because of the heavy losses caused by the fact that the seed cannot live up to the purity requirements. Wheat is dropped, while rye/triticale is increased to about 30% of the acreage and spring barley from 19 to 39%. This change is due to the lower losses in rye/triticale and spring barley than in wheat. Set-aside takes up 25% of the acreage.
5. Dairy farms on clayey soil: Here, too, the set-aside acreage is only 10% in order to meet the harmonisation rules. Wheat is dropped almost entirely in favour of more wholecrop, which increases from 9% to 26%. This crop must replace mangolds and maize, which are difficult to grow without using pesticides. There is about 6% with winter barley followed by winter rape. Combined, these two crops compete well with the other crops.
6. Arable farms on sandy soil: The set-aside acreage is close to 30%; wheat is omitted, being replaced by rye/triticale. Spring barley is still grown on about 1/3 of the acreage. There is about 9% with seed grass, which, despite the heavy losses of about 50%, can compete with the other crops. There is already approx. 5% seed production at these farms in present production – mainly rye grass, which thrives on sandy soil.P
7. Pig farms on sandy soil: The set-aside acreage remains at 10% to enable the farms to meet the harmonisation requirements. Wheat is replaced by rye/triticale, while the acreage with spring cereals is increased by about 10%. Here, too, wheat is dropped because of the heavy losses in this crop. There are about 15% with rape, peas and seed grass.
8. Potato producers on sandy soil: The set-aside acreage rises to approx. 30%. Wheat is omitted, being replaced by winter barley on about 22% of the acreage. The spring-barley acreage rises from 28 to 41%. Potatoes are dropped apart from a small production of ware potatoes (3.3%), which we estimate can be sold to consumers with a preference for Danish potatoes who are willing to pay a higher price for them. Winter barley also does well in present production compared with wheat and rye/triticale.
9. Dairy farms with low intensity on sandy soil: The set-aside acreage is kept at 8%. Mangolds and maize are dropped because it would be costly to keep them in a 0-scenario. Instead, coarse fodder is produced from wholecrop and rotation grass. Wheat is dropped and the spring-cereal acreage is kept at around 1/3 of the acreage.
10. Dairy farms with high intensity on sandy soil: The set-aside acreage is reduced from 6% to 3.5%. Mangolds and maize are no longer grown because of the high cost of growing them in a 0-scenario. They are replaced by coarse fodder produced from wholecrop and rotation grass. Cereal for maturity are grown on only 5% of the acreage compared with 16-20% at present.

Mechanical weed control

In a 0-pesticide scenario treatment with herbicides would be extensively replaced by mechanical weed control. It is estimated that this, together with preventive measures, would result in an acceptable level of weed control. However, it severely restricts what can be grown in the different crop rotations. The level of control would generally not reach the level achieved with chemical measures. We would therefore expect the quantity of weed in many fields to rise, contributing to crop losses and increased harvesting and drying costs. We estimate that the weather, in particular, would regularly limit the success of the control measures, which might mean that some fields and crops would have to be abandoned. The long-term proliferation of weeds in the proposed crop rotations is not known either. Particularly on certain types of soil, including organic soil, major problems could arise with weed control, which might mean having to take the acreages in question out of cultivation and putting them under grass. The capacity of the mechanical control methods is generally lower than that of chemical control methods, so phasing out pesticides could have consequences for the size and structure of farms - especially farms with a large production of potatoes.

Resistant varieties

In the scenario without pesticides, the cultivation of resistant varieties would become of increasing importance. However, even if the most resistant varieties were chosen, it would be impossible to avoid attacks by diseases because the existing assortment does not include varieties with good resistance to all major diseases in, for example, cereals and potatoes. The long-term effects and any losses as a consequence of increased pressure of infection when control measures are omitted cannot be determined from the existing plot trials.

There are descriptions of several alternative methods that are being developed to replace dressing agents (Nielsen et al., 1998). However, none of the methods have reached a stage of development at which they could replace the chemical methods. For this reason, the sub-committee has incorporated an assumption that control of seed-borne diseases would be sufficiently ensured by the necessary dispensation schemes in order to minimise the losses.

With our present level of knowledge, there are very few possibilities of reducing pest attacks by alternative methods. Attacks will regularly cause significant crop losses and reduce security of cultivation.

Cultivation without growth regulators is widely practised today through the use of short and strong-stemmed varieties. If tall and more competitive varieties were used, there would be an increased risk of lodging if the nitrogen level was not reduced at the same time (by about 30 kg N). A 30-kg reduction of nitrogen would mean a generally lower yield potential.

Annual fluctuations in yield losses

The losses that could occur must be expected to fluctuate considerably from year to year. That would reduce the existing security of cultivation. Similarly, there would be considerable fluctuations between the different farms, depending on various factors, including the type of soil and the existing weed flora. This would probably increase the differences already seen today. The success of the individual crops and crop rotations would largely depend on how well the individual production manager tackled problems with pests, among which weeds are deemed to be the biggest problem.

We estimate that the crop rotations described could be practised, although typically with 10-25% yield losses compared with present production. Their course is very uncertain, particularly at farms with large proportions of special crops, where the losses can be expected to be closer to 50%. Success would depend on more farsighted planning of production, with pests "controlled" to a far greater extent than at present by a combination of crop rotation, preventive, indirect treatment and direct action. The manager’s decision would therefore necessarily be based on controlling pests rather than only on optimising production on the basis of traditional, economic considerations. This change would require considerable input with respect to training and supplementary training.

Security of cultivation would thus very much depend on how farsighted the individual production manager was because the 0-pesticide solution depends on cultivation elements that are ahead of their time as far as recognition of the problems is concerned. The present security of cultivation rests largely on the fact that pesticides can be used to minimise damage.

Risk of heavy losses

Table 5.8 gives average losses for different crops, together with an estimated maximum loss to illustrate the magnitude of the losses that could occur in individual years countrywide. In situations in which a pest developed to a high level, the losses for commercial crops would lie between 22% and 100%, which can be taken to mean a reduction in the security of cultivation. It is extremely difficult to say anything about how often these maximum years occur, mainly because they depend very much on the weather. For fungal diseases in cereals, there were almost max. outcomes in the years 1987, 1989, 1990, 1996 and 1998 – in other words, in 5 out of 14 years, corresponding to approx. every third year. The attacks in 1989 and 1990 were particularly severe in wheat as a consequence of cultivating a variety that was sensitive to yellow rust on large acreages. In a situation without fungicides, one would expect such a variety to be discarded. In rape there are major attacks of disease approximately every 5 years in a considerable part of the crops. Stapel (1983) has calculated the variations in the degree of attack of both diseases and pests for a 100-year period on the basis of records from monthly reports. This material shows the large annual variations.

However, it is important to stress that there are also considerable fluctuations in yield from year to year in the present, conventional production, due mainly to variations in precipitation, see figure 5.2 (Kjær, 1998).

Mycotoxins

An assessment has been carried out of the risk of an increased occurrence of mycotoxins in harvested crops (Elmholt, 1998). The principal mycotoxins produced in Denmark come from Fusarium and Penicillium fungi. There are no clear indications that the present use of fungicides significantly reduces attacks on cereals by these fungi. It can therefore not be inferred that a phase-out would increase the attacks. Increased quantities of mycotoxins could occur indirectly. In connection with increased occurrences of weeds and the increased risk of lodging, getting the harvested cereals dry could thus become increasingly problematical. This would lead to increased costs for drying cereals and could affect the quality of the cereal, including the content of mycotoxins. Studies of ochratoxin A in flour and grain carried out by the Danish Veterinary and Food Administration showed a tendency towards a higher content in the products from organic farms (Anon., 1998). This could have been due to a higher water content in the harvested grain, combined with inadequate drying.

Soil preparation and mineralisation

Increased mechanical soil preparation, as a significant weed-control factor, can, if a lot of the work is done in the autumn, cause increased leaching of nitrogen. Autumn ploughing results in leaching of approx. 15 kg more nitrogen than spring ploughing. Stubble-harrowing in the autumn, which would be needed to keep couch grass down, also results in increased leaching of nitrogen, the increase being about 10-15 kg/ha (Møller Hansen & Djurhuus, 1996). On the other hand, cultivation of large acreages with second crops must be expected to reduce the risk of nitrogen leaching. The risk in the different scenarios has been analysed by the Sub-committee on Environment and Health.

Reduced need for nitrogen

The smaller cereal yields in the proposed 0-scenario imply a reduced need for nitrogen of 33,000 tonnes for cereals, while an increased acreage with grass and winter rape implies an increased need for nitrogen in relation to fertilisation in present production. Without pesticides, the need for nitrogen would be reduced by a total of 12,000 tonnes.

In the 0-pesticide scenario it would similarly be possible to reduce the amount of phosphate and potassium fertiliser applied. The change in the need for fertilisation has been calculated as the difference in removed commercial product. The increase in rape and pea acreage implies an increased need for phosphate of 4,000 tonnes and a smaller need for potassium of 36,000 tonnes.

There have been very few trials showing the effect of a 0-pesticide scenario compared with conventional cultivation in conditions in which allowance is also made for incorporating alternative control methods. In the following two trial series the cultural practices have been adjusted, but the crop rotation has not been changed.

One year’s result from Køge-Ringsted farmers association

In 1998, two trials commenced in two localities in which crop rotations without use of pesticides are being evaluated in comparison with a crop rotation with a low-input level of pesticides (Kjærsgaard et al., 1998). The crop rotation comprises peas, wheat (1st yr.), wheat (2nd yr.) and spring barley on clayey soil, while on sandy soil it comprises peas, wheat, rye and rye. The trials are multi-year trials and, where possible, include cultural practices in the 0-scenario (mechanical weed control, resistant varieties, late sowing, lower nitrogen level, etc.). The pressure of weed on the land used for the trials is relatively limited.

The results from the first trial year showed in an average of all crops a lower yield level of 23 hkg/ha, which, after inclusion of variable costs and crop earnings, results in a reduced average income of DKK 1,420/ha. The yield losses in the trial year were large owing to severe attacks of septoria and aphids in wheat, brown rust in spring barley, thrips in rye and pea weevil and pea moth in peas. The weed problems are not thought to have been particularly serious in the trial year. This first year’s trial does not tell much about the degree of proliferation that can be expected in the trials. The yield losses in 1998 are estimated to have been higher than in an average year but are a very good indicator of realistic losses in a year with severe pest attacks. Compared with the calculated losses in the 0-scenario, in which the total cereal loss is 23%, the level from Køge-Ringsted is over 30%.

0-pesticide cultivation of malting barley

In the period 1992-96, DIAS carried out 24 trials with 0-pesticide cultivation of malting barley. In the trials, the only adjustment made to cultivation practice was the introduction of mechanical instead of chemical weed control. The yield loss compared with conventional cultivation averaged 11%. Where a more resistant variety was grown, the reduction in yield was approximately halved (Rasmussen, 1998). The trials were not sited in crop rotations with permanent 0-pesticide cultivation. It can thus not be judged from these trials whether weeds would proliferate to such an extent over the years as to cause major losses. The losses in these trials lie 5-7% below the level fixed in this work.

9.9 Conclusion concerning 0-scenario

10-25% yield loss

This chapter suggests what a 0-scenario could be like for 10 different types of farm. It is estimated that the crop rotations described could be practised, although typically with a 10-25% loss in yield compared with present production. There is great uncertainty about its course, particularly at farms with large proportions of special crops, where the loss of yield is expected to be closer to 50%.

Changed crop rotations

In practice, a 0-pesticide scenario would require considerable restructuring of the farms, including crop rotations with a significantly smaller proportion of winter cereals (max. 40% of the crop rotation) in order to reduce the problem of grass weeds. To continue meeting the requirement concerning 65% green crops, second crops have been incorporated in connection with the cultivation of spring cereals. Also incorporated is a wide range of cultural practices that would be needed to minimise pest problems.

Loss in individual crops

Percentage losses as a consequence of 0-pesticide cultivation have been estimated for all crops. The percentage losses for the individual crops have been broken down between different pests. The total average production loss for different crops varies between 7% and 50%. In potatoes, the loss from potato blight, for example, would be about 38%, while the yield from seed grass would be halved due to weed problems and problems with removing weed seed. In wheat, the total loss is estimated to be 27-29%,. Of this, 7-9% is due to leaf diseases, 14% to weed and damage to the crop in connection with harrowing, about 3% is due to pests, and about 7-8% is due to other factors such as postponement of the sowing time and use of resistant varieties.

The smallest losses estimated are in grass and winter rape, which would be affected only minimally. Considerable fluctuations can be expected in the losses that could occur, which would reduce the existing security of cultivation. It must be expected that certain productions with strict requirements concerning purity and freedom from disease would have to be abandoned. Estimating the percentage losses in a 0-pesticide scenario is encumbered with considerable uncertainty because of a significantly different epidemiology and population dynamics for the pests. For example, there is at present only very limited trial documentation on which to base an evaluation of a 0-scenario.

Dispensation for treatment with dressing agents

In the event of pesticides being phased out the sub-committee proposes that dispensation be granted for prevention and control of seed-borne diseases in the early generations of seed because the consequences of an uncontrollable proliferation of seed-borne diseases are incalculable and could result in heavy losses. In fields with severe attacks of stinking bunt, the crop would be worthless as food for either animals or humans. In spring barley we estimate that the combination of treatment of the first generations with a dressing agent and need assessment of the C2 generation could be practised, whereas for winter cereals a more detailed evaluation would be required to determine whether a need assessment of C2 was feasible with the very short time between harvesting and sowing. If treatment of the first generations up to and including C1 with a dressing agent were retained and were followed by a need assessment of C2, the treated acreage could presumably be reduced to less than 10% of the present figure. Such a strategy would have to be followed up by information and advice to ensure that farmers changed their sowing material.

Change in contribution margin II

For the crop rotations used at dairy farms, restructuring would be relatively easy and cause only limited losses, while the biggest loss would be suffered in connection with specialised arable farms, which have a substantial production of, for example, seed, potatoes and sugar beet. It is not deemed realistic to maintain these specialised productions if pesticides are banned altogether. Economic analyses of contribution margin II for whole types of farm, if the present proportion of special crops is maintained, thus show, in relation to present production, an average reduction of 4-8% for dairy farms on sandy soil, 39% and 48%, respectively, for arable farms on sandy soil and clayey soil, and 50% and 93%, respectively, for arable farms with seed production and sugar beet, while the loss for potato producers would be 66% (table 10.9).

Economically optimised crop rotations

Besides the crop rotations proposed with a view to reducing the level of pests and maintaining the present acreage with special crops, we have set up some types of farm based on a mixture of agronomic and economic factors in an economic optimisation model. In a 0-scenario, these farms would almost totally phase out special crops. That accords well with the misgivings expressed about these crops, for which heavy costs can be expected for weed control, together with losses from, for example, potato blight. It is therefore natural that other crops would oust these crops in a 0-scenario. Owing to the substantial losses in many crops, the economy of the farms would be impaired to such an extent that set-aside would become advantageous. The proportion of set-aside would increase to about 30% at pure arable farms, where handling of liquid manure and harmonisation rules do not have to be considered. That would give a total of 18% set-aside, which is in excess of Denmark’s total quota of 15%. In the purely agronomic 0-scenario, some rape and peas have been proposed in several crop rotations. These crops would not be found competitive where economic optimisation was practised but would be replaced by rotation set-aside, which is also assigned a previous-crop value. Spring cereals would similarly generally gain ground at the expense of winter cereals.

CM II in economically optimised crop rotations

Economic analyses of contribution margin II for these optimised farms, where there are largely no special crops, show, in relation to present production, an average reduction of 21-24% for dairy farms on sandy soil, 26% and 34%, respectively, for arable farms on sandy and clayey soil, and 35% and 39%, respectively for arable farms with seed production and sugar beet, while the loss for potato producers would be 51% assuming 1995/96 prices. The losses would be significantly lower at the optimised arable farms with special crops compared with the more agronomically optimised crop rotations (table 10.9).

Meeting quality requirements

The success of a 0-pesticide scenario would depend to a great extent on being able to meet current quality requirements concerning, for example, seed, seed potatoes, starch potatoes and similar. In the case of crops grown in rows, manual weeding would be necessary until new methods were developed. Whether it would be possible to procure sufficient manpower for such very seasonal work is another question that remains to be answered – and one that could make continued production of sugar beet difficult. The lower yields and, in some cases, higher additional costs for, say, weed control and drying, must be judged in relation to whether a premium could be obtained for crops that had not been treated with pesticides.

The percentage losses given in the 0-scenario are deemed to be relatively optimistic. The reasons for this view are as follows:

	The expected losses from weeds have been put at half the losses observed at organic farms today. On the other hand, larger losses have been added as a consequence of expected increased activity with mechanical control compared with existing organic farms.
	It is not known whether epidemics of diseases in a situation without control measures would result in faster proliferation rates and faster reduction of the effect of the incorporated resistant genes.
	Adjustments have not been made for situations in which the assumptions used do not hold good – in the case of heavy pressure of weeds and species of weed that are difficult to control on, for example, organic soil.
	Account has not been taken to any great extent of the fact that the production management would not be optimal in all situations.

Unused alternatives

The sub-committee believes that there are several unused alternatives to chemical control methods that could improve the cultivation conditions in a 0-pesticide scenario. Together with better utilisation of disease resistance, broader distribution and further development of methods of mechanical weed control are among the most obvious. Adjustments to crop rotations would have a powerful effect when pest prevention becomes more important than direct pest control. We consider that the demand for alternative methods would, in itself, promote and stimulate the development of alternative methods.

The Sub-committee on Production, Economics and Employment has evaluated the total production figures in a 0-scenario on the basis of a socioeconomic model. Concerning the production of sufficient feed units to maintain the present livestock production, in the 0-scenario a production is planned at the dairy farms that would maintain the necessary production of feed units. In the case of pig farms, it has been estimated that a reduction in cereal production could be made up for with imports from other countries. The economic consequences of such restructuring have been included in the economic analyses.

References

Anon. (1998): Monitoring programme for ochratoxin A in grain and flour, 1998. Report IFE from the Danish Veterinary and Food Administration.

Elmholt, S. (1998): Concerning the interaction between pesticides and toxins in agricultural crops. Report prepared for the Pesticide Committee, 1998.

Hansen, J.G. & S. Holm (1996): The weather determines the need for control of potato blight. 13th Plant Protection Conference, Diseases and Pests. SP Report No. 4, pp. 41-51.

Holm, S., Knudsen, P.B., Mathiesen, A., Højmark, J., Tolstrup, K. (1999): Problems in potato production with total or partial phasing out of pesticides. Report prepared for the Pesticide Committee.

Kjær, L. (1998): Report on data extracted from the Danish Agricultural Advisory Centre’s field trial database. Report prepared for the Pesticide Committee.

Kjærsgård, J. (1998): Pesticide-free farming. Arable Farming Report from Køge-Ringsted Farmers’ Association, 1998.

Møller Hansen, E., Djurhuus, J. (1996): Nitrate leaching and soil preparation, Vand and Jord (Water and Soil) No. 4, 1996.

Nielsen, B.J., Borgen, A., Scheel, C., Nielsen, G.C. (1998): Evaluation of the overall consequences of phasing out pesticides. Compilation of existing knowledge on possibilities of preventing and controlling problems with seed-borne diseases. Report prepared for the Pesticide Committee.

Rasmussen, I.A. (1998): It does not always pay to use pesticides. Jord og Viden (Soil and Knowledge), 22.10.98, 143 (22): 4-5.

Stapel, C. (1983): Plant diseases in Denmark. 100 years’ reports collected at the Plant Protection Centre, Danish Institute for Plant and Soil Science, 1984.

Ørum, J.E. (1998): Consequences for production economy of phasing out pesticides – optimal pesticide and land use for 10 types of farm in five selected scenarios. Report prepared for the Pesticide Committee.