Kvælstofanvendelsen i dansk landbrug - økonomi og kvælstofudvaskning

English Summary

This report presents three studies which separately discuss problems linked to the research basis of regulating the agricultural use of fertilizers in Denmark. Analyses with behavioural descriptive models as well as analyses based on monitoring data are presented. In the survey both representative financial data of a sequence of years and more detailed behavioural data of a shorter period from a smaller section of farms are employed.

Current problems

The studies present different problems which are current in connection with the economic and environmental basis towards regulation of agricultural use of nitrogen in Denmark. The focus of all three projects is the use of the fertilizers - inclusive both consumption of commercial fertilizers and livestock manure. In all three parts the main points are analysis of the differences on farm type level and not least the adaptation mechanisms which the different farm types can use when there is a change in the environmental regulations.

New surveys of the use of fertilizers - and regulation

Analysis and modelling of the agricultural use of nitrogen and the nitrogen loss is not a new research field - on the contrary it is a field where several Danish as well as international studies and results are available. Many of the former analyses are on a theoretically level while the few empirical analyses are insufficient. Thus, the analyses presented in this report are not the only ones in this field but represent some of the newest Danish surveys where some of the missing points of the former analyses are taken in consideration in connection with statements and modelling of the use of fertilizers. Furthermore, it is shown that there are still some unsolved questions linked to the analyses of the nitrogen consumption and the resulting effects on economics and environment.

Model basis and results

The report includes comparison and estimation across very different models and analyses both with regard to model basis and results. Therefore this report can be a contribution to proceed in the development of the analysis methods in connection with estimations of the agricultural nitrogen loss regulations. All three parts of the project discuss subjects which give more knowledge about the behavioural reactions of the farm types as to the use of fertilizers. Also many of the aspects which are analysed in the report are important in relation with the work of environmental and nature related problems in future. For example, the aggregated analysis of the use of fertilizers in part A and the analysis of the use of fertilizers in part B can be used to gain new knowledge about the use of phosphorus and potassium, too. Furthermore, the discussions about the basis for regulations and the agricultural adaptation mechanisms in part A and C are essential in the future discussion about regulation of agriculture.

Focus and results of the individual analyses

Part A: substitution between fertilizer types centrally

In part A the differences of the behavioural reactions of the farm types as to consumption of fertilizers based on the financial data of Danish Institute of Agricultural and Fisheries Economics for a period of 20 years are analysed. The study forms the basis towards improvements for the quality of the model when handling realistic modelling of the use of fertilizers in the sectormodel "ESMERALDA". This model has been applied before in connection with quantitative estimations of the regulation of the agricultural nitrogen use. So far some of the limitations of the model when used to environmental analyses are that behavioural differences conditioned by the soil type have not been incorporated explicit as well as differences of price elasticity conditioned by farm type. Concretely, this has lead to that the adaptation mechanisms which possibly will be used by the farmers have been difficult to interpret from the model results. For example, the substitution between commercial fertilizers and livestock manure when the utilization of the livestock manure is increased. The further development of the model basis will done in other already started research projects and the analyses which are presented here forms the basis of the further development.

Demand for fertilizers

In the project the price elasticity on the demand for fertilizer of farm types situated on sand and clay soil respectively and for different farm types is estimated. The elasticity indicates the possibilities of factor substitution. In other words, it is analysed whether the combination of fertilizers with commercial fertilizer and livestock manure will change as a reaction on the changes of regulation and/or price.

Soil types

The analyses of part A indicate that there are no significant differences of the elasticity figures and thereby the factor substitution between the two soil types even though there is very small indications that the elasticity figures are bigger numerically on sand soil for livestock farms - so, the use of commercial fertilizers is replaced more quickly with livestock manure than on clay soil. Even though there seems to be no variation in the adaptation between soil types for a certain farming method there is still a difference in the fertilizer response on sand and clay soil as a reaction to the differences between the individual farming methods when we analyse the problem aggregated on the national level. This is due to the fact that livestock farms mainly are situated on sand soil while crop and part time farms comparatively are represented on the Danish clay soil regions.

Farm types

Further, the results show that the price elasticity figures are numerically a little bigger for pig farms than the other farms. But the results also show that the use of commercial fertilizer forms a smaller part of the total use of fertilizers in pig farms than the other farm types - something that are due to both difference in choice of crop and the possibility for utilization of the fertilizer effect of livestock manure. This leads to a maybe surprising but realistic conclusion of the survey that adaptations of the use of factors as a consequence of price changes or demands towards use of commercial fertilizers are poorest for the pig farms. This may be different for regulations which are aimed at the total use of fertilizers on the farm - that is both livestock manure and commercial fertilizer as well as other sources of nitrogen input.

Part B: Empirical survey

In part B an empirical survey of the use of fertilizers on a few selected farms of LOOP (the fields of the agricultural catchment monitoring programme). Some factors which can explain why farmers use to much fertilizer compared to the agreed levels are discussed. Here the analysis of transport distances and the influence of this is in focus.

Overfertilization

The first part of the study presents data of the use of fertilizers in the catchment area. This survey shows that overfertilization takes place on single fields on more than half of the farms which are included in the survey and not as believed just on some few farms. The term overfertilization is defined as levels beyond 20% of the standard use of fertilizer. Yet, from a economic point of view the term is missleading as it must be assumed that most farmers fertilize their crops with regard to the financial yield. Therefore the registered overfertilization must be an indication that the factors which effects the fertilizer practice of the farmers are composed of many different aspects: practical, financial, experience etc. Aspects which are not reflected in the methods used to determine the need for nitrogen of the crops.

In addition to the empirical survey it is examined whether overfertilization vary according to farm types and not surprisingly it is found that overfertilization is more common on livestock farms than on crop farms.

Application equipment and transport of livestock manure

To illustrate the importance of transport distances and application methods an examination of the financial consequences of partly to use different forms of application technology and to transport livestock manure over various distances is made in the second part of part B. The survey shows that it has been profitable financially to use trailing hoses in the 90ies at the expense of conventional wide spreading which (other things being equal) gives a better adaptation of the livestock manure.

The analysis of transport distances of a selected data set showed that the main part (about 90%) of the fields were less than 2 km from the livestock manure storage. Within this distance a bit more than half of the fields received livestock manure while only a small part the fields situated more than 2 km away received livestock manure.

The study of the transport expenses shows that the expenses increase significantly with increasing transport distance. Especially the spreading of cattle manure is expensive as the efficiency is smaller than that for pig manure. Maybe it would be profitable to employ several smaller livestock manure stores and thus reduce the transport expenses as it would be possible to use lorries, but this is not examined in this project.

Part C: Effects and regulation

In part C existing regulations and studies where different models are applied to analyse the agricultural use of nitrogen and nitrogen strain as well as the effects of regulations are presented. Both regulations within the Action Plan II and other interventions - different levy types among others - are presented.

Sector and farm models

The shown estimations are based on respectively the agricultural sector model ESMERALDA, farm models (optimising models) and with data from the agricultural catchment monitoring programme with leaching functions. The analyses based on the farm type models and ESMERALDA both reflect how the farms til react given that the model basis are realistic. The model results point at various conflicts in the regulation. For example nitrogen-fixing crops and spring cereals and also increase of livestock production as a consequence of a levy on commercial nitrogen fertilizer. Analyses based on the data from the agricultural catchment monitoring programme do not reflect the behavioural reactions in agriculture but show the effects on the nitrogen leaching that a given regulation can have - if the farmers follows the demands as expected - but without a behavioural adaptation for that matter.

Strengths and weaknesses

In this part there is also focused on the differences between the models and the various strengths of the models when applied. In the existing form the ESMERALDA model which is related to the sector level has its strengths in giving results of the total effects of the regulation for the agriculture as a whole. However, the aggregated description of the agricultural production imposes restrictions on the possibilities to analyse very detailed levies and regulations as well as the use of the results for leaching estimations is connected with restrictive assumptions. Analyses with the farm type models have their strengths in their precise description of the productions processes of the chosen farm types. Therefore the results are also very specific for the modelling farms and can only be used to indicate the effects of the regulation. Compared to the other two analysis methods the data from the agricultural catchment monitoring programme has its strengths in the wide extension of the data collection. With that it is possible to examine the effect of compliance with the regulation on a number of farms. But as mentioned they are not combined with a behavioural modelling which would make quantification of the economic effect of the regulation or the effects of levies and similar adjustments possible.

Conclusions of the three parts of the project

Further development

A further development for all the three presented analysis methods is ongoing as to improvement their employment for environmental political analyses. This applies both for the modelling of the use of fertilizers and the delineation of nature determined conditions like soil types for example. In the light of the latest regulation initiatives it seems relevant that the analysis models are improved to illustrate regional differentiated analyses including the necessary description of the agricultural production processes which could make it possible to analyse complex regulations. Examples of regulations which more than ever reflect the nature determined and farm structural conditions which are decisive towards the agricultural environmental and nature effects.

The utilization of livestock manure and prices on fertilizers

While it in part B and C is concluded that the possibilities to utilize the livestock manure in pig farms are good compared to cattle farms because of the composition of the livestock manure and also that the costs by using the manure is lower than for cattle farms it is concluded in part A that the possibilities to adapt the use of manure in pig production are bad if regulations are aimed at the consumption of commercial fertilizer. At first this seems to be a contrast but it is due to the fact that the use of commercial fertilizer is a relatively small part of the total use of fertilizers and manure in the pig farms. Furthermore, the results of part B indicate that the transport costs are considerable and therefore the costs of using livestock manure will be significant on large farms where there is a big distance between store and field. With the increasing sizes of pig farms this could mean that the costs by using livestock manure exceed the fertilizer effect. This is also supported by the results in part A. Therefore one overall conclusion of the three studies (other things being equal) is good substitute possibilities between commercial and livestock manure on pig farms but as the amount of livestock manure covers the need of the crops on many farms and the costs by a better utilization is considerable when the livestock manure has long transport distance the effect of a commercial fertilizer levy seems limited on these farms.

If the regulations are aimed at the total input of nitrogen to the farm this would probably improve the result. In connection with this report no estimations to illustrate the quantitative effects of this kind of regulation have been made.

Other adaptation effects of regulation

On top of the estimated effects on intensity and factor combination other effects in connection with increase of the fertilizer price can be expected. Both in part A and C it is emphasised that the price on fertilizer could have some influence on choice of crop and livestock density. This effects the demand for fertilizers on farm level. If the price on fertilizer increases it could be expected that the effect would tend toward a lower consumption of fertilizer. The analyses of part C indicate that this could mean negative environmental effects as the estimated leaching increases when choice of crop is changed from winter to spring cereals. Further the estimated results discussed in part C indicate that a rise in the fertilizer price could cause an increase in life stock density which will counteract the decrease the consumption of fertilizer. On more aggregated levels (for example on the regional or sector level) this could lead to structural changes.