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Regional planning as a strategy
Landscapeand Urban Planning, 18 (1990) 265-273 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands
265
Regional Planning as a Strategy
D. SIJMONS State Forest Service, Utrecht (The Netherlands) (Accepted for publication 22 August 1989 )
ABSTRACT Sijmons, D., 1990. Regional planning as a strategy. Landscape Urban Plann., 18: 265273. In landscape planning the emphasis up till now has been predominantly on the preservation of historic values. A shift in attention to the moulding of new landscapes requires focusing on the analysis of elements and forces that underlie the formation of the existing landscapes and also an understanding of their potential for
future development. This new course must be taken for the sake offuture rural landscapes. In view of the uncertain developments in future land use the new landscapes need to be planned in a flexible way, allowing for dynamic development without damage to stable systems. This sort ofplanning is most viable when prepared and implemented at a regional level.
INTRODUCTION The modernization and industrialization of agriculture is the driving force behind the process of change in rural landscapes. One could say that agriculture in The Netherlands, when seen in a rosy perspective, is a highly successful branch of industry that has succeeded in creating a spectacular rise in productivity in a very short time. All this, of course, has been accompanied by negative environmental effects. This impact on the environment is as yet only partly visible in the decrease of differentiation in species, both in flora and fauna. The other effect is at the moment still invis0169-2046/90/$03.50
0 1990 Elsevier Science Publishers B.V.
ible: the ticking time bomb of the percolating nitrates and heavy metals into the subsoil, on their way to our fresh water resources. The intensification of agriculture and the accompanying improvements in the external production system was followed by a dynamic change in the layout of the land. This implies a fading away of the original identity of various manmade landscapes. Relations between landscape units are disappearing and only remnants of the once coherent patterns survive. The tendency towards more uniformity is caused by developments in rural engineering and in breeding techniques. Conditions in which everything can happen everywhere are
Fig. I. First stage of a dynamic landscape development in an agricultural area in the Eastern part of The Netherlands (Achterhoek). of 1862, the original scale was I : 50 000. Black dots are forests. the grey tone is “waste land”. Source: Topografische Dienst. Delft.
Topographic map
REGIONAL PLANNING AS A STRATEGY
267
Fig. 3. Third stage of development Topogratische Dienst, Delft.
of the same area shown in previous figures. The situation in 1952, the original scale of the map was 1: 25 000. Source:
REGIONAL PLANNING AS A STRATEGY
269
270
approaching, The variety in soil conditions for instance has partly lost its differentiating effect. A planning methodology should be devised for a modernization of our cultural landscapes that reintroduces a unified way of dealing with the process of change and development. PHYSICAL CHANGE
OF LANDSCAPES
The call for better planning is not a new one in The Netherlands: back in the 1960s policies were developed to modify or call to a halt the developments that lead to environmental degradation. In some areas physical planning agencies tried to regulate this process by setting up guidelines that would stipulate the degree, the way and the scale in which agricultural and natural land use types should be mixed. The nature conservation agency has converted this policy into measures that enable farmers to sign contracts stipulating a form of farm management in which for instance the disturbance of birds’ nests is prevented and the maintenance of non-functional hedges and tree stands is assured. Finally, landscape planners have tried to fit socioeconomic developments into the fabric of the existing landscape. Where this proved to be impossible it was attempted to fit in new developments in such a way that the outcome somewhat resembled the historical landscape (Figs. l-4). THE REMEDY FOR LANDSCAPE PLANNING
This analysis leads to the inevitable and painful conclusion that all these efforts, based on good intentions, accompanied by lengthy consultations and procedures, and costing large amounts of money, have not led to satisfactory solutions. In analysing the situation more closely, we must conclude that for the major part of the rural landscape the guiding planning policies of the past and their familiar strategies trying to Iit the new into the existing, or to make the
“modern” look like the “old and familiar” are no longer realistic. This is so for the simple reason that the historical identity of places and patterns has dissolved so much that we cannot find enough points of reference on which to base our prospects for the future. If we reject a historicizing approach to the planning of rural areas we must focus our attention on those patterns and processes that are the formative elements to be used in moulding new landscapes. By exploiting these elements we should be able to create an attractive and viable landscape. How should this new and demanding task be tackled? There is an urgent need to formulate a new course of action. We must recognize that the creation of new landscapes cannot be left to the free interplay of social and economic factors. Planning is needed. But our policy makers have not demonstrated a great deal of interest in problems such as the loss of identity of landscapes. This is not an issue of political concern and will never be the dominant argument for action in this respect. An attempt to plot out a new course is based on the following general considerations: - When the impending loss of the identity of the landscape is not a political issue the action of both the policy makers and the planning bureaucracy will normally be spurred by the needs and claims of various land use types and their mutual conflicts, or a misfit between land use and existing physiographic conditions. - A new course of action must be based on a consensus about quality requirements. Future landscape quality will depend on the possibility to create a new coherence among economic, ecological and aesthetic qualities. - Planning and management actions should be coordinated in a better way. This consideration is linked to the notion that highly praised qualities of the now disappearing historic landscapes can be attributed to the continuity and unity of both management
REGIONAL PLANNING
AS A STRATEGY
controls and land use types over a long period of time. The highly valued differentiation in landscape types can be seen as the product of deviations from the main course of development caused by circumstances in specific locations during certain periods of time. - With these considerations in mind an effort is currently being made in landscape planning in The Netherlands to develop new design strategies that offer alternatives to the prevailing approach which is unable to solve the existing tension between claims arising from the needs of agricultural production and those of nature conservation. A NEW STRATEGY FOR REGIONAL PLANNING AND DESIGN
On the basis of the previous discussion we can distinguish two key factors: - how to deal with the factor “time”; - how to deal with the issue of “uncertainty”. The planning and design of new landscapes involve, among other things, the manipulation of living material. Here, the factor of time is of prime importance. It is one that can never be manipulated by man. Nature has invested much time in existing forest land, in hedgerows, and even more so in certain ecosystems as well as in soil formation processes. When locating new woodlands, greenbelts and nature development projects, one must always take into account the fact that nature is the main contractor and should be given ample time to do its job. This is not a easy condition to full3 within the standard short term planning periods adopted in conventional physical planning procedures. One must bear in mind that even the so-called “temporary” tree stands, such as poplar timber for the paper industry, need three consecutive planning periods to mature. An important conclusion is that some land use types in rural areas apparently need a high degree of stability in space and time, and do
271
not permit a major disturbance in external conditions. These types of land use are: - Nature conservation and development; - Forestry and woodlands; - Hedgerows and tree plantings; - Fresh water retention and supply; and derived from these, to a certain degree: - extensive forms of outdoor recreation - certain types of low input farming. In view of their needs these land use types can be designated metaphorically as “the slow turning wheels”in the landscape. The planning and design problem here is to develop a strategy warranting the survival of “low dynamic” land use types by not letting them be overrun by extreme dynamic land use: the “j&t turning wheels” in the landscape, such as agriculture and urban activities. This brings us to the second issue: dealing with uncertainty. It has proved to be extremely difficult to predict the direction of dynamic processes within certain land use types. In looking back at, for instance, post-war developments in agriculture we see several moments when forecasts were made about its prospects. We can now conclude that all these forecasts have misjudged some essential aspects and have proved to be inaccurate. It is impossible and even undesirable to try and predict technological development in agriculture and combine these predictions with attempts to slow down or prevent this. Technological innovation in the future will continue to offer spectacular opportunities for the agricultural entrepreneur to increase productivity and to reduce costs. Every decision to invest or de-invest will eventually be made and implemented at the level of the individual agricultural enterprise and it is therefore very difficult to predict developments and their visual and ecological impact. The same goes for the forecasting of government measures to improve external conditions for production. Predicting the future will become even more haz-
272
ardous if one takes into account the possibility of the so-called “trend breaks”. Trend breaks may have various origins: - Agriculture is at the moment surpassing the carrying capacity of the natural environment. In some places the very survival of agriculture itself is at stake, especially where soil quality is deteriorating. Counter measures are required to stop this process. - Agricultural production in the whole of Europe must adapt to the rules of an open market. The issue of over-production may be solved in various ways, such as a drastic reorganization, the imposition of quotas, the extensification of production, set-aside programmes, etc. One can distinguish a rupture between the period when a raise in production was the central objective and the new era where both makers and private enterprise look upon the lowering of production costs as a primary goal. - A shift in consumer needs can be observed at the moment: from quantity to quality of products and to a greater variation in types of product. Agriculture will have to meet this challenge in an adequate way. The uncertainties caused by these trend breaks cannot be reduced by an increased research effort or better judgement on the part of planners. We will have to learn and live with uncertainty. The only certainty might well be change itself. The consequence for landscape planners is to set up plans that incorporate a marked degree of flexibility. Flexibility can only be achieved by the demarcation of areas for agricultural use and by setting up a structural framework in between and around these areas that does not collapse whenever developments in agriculture change in scope and direction. This implies a separation in space of those land use types that are in conflict in terms of pace of development, and the use of design models for agricultural land use that can absorb a broad range of types of development. In many cases this will come down to a
D. SIJMONS
search for a layout with stable configurations in the form of interconnected zones containing those land use types that depend on a low degree of dynamism. These zones form a body, or framework, enveloping types of land use that demonstrate a high degree of dynamism. The framework is more or less independent of the dynamic areas it encloses and agriculture can be offered a wide array of developments as long as it stays within the limits of the environmental boundaries. This type of strategic planning is most effective when applied at a regional level of scale, because: complete landscape units can be taken into account; nature development can be analysed at the level of interrelated ecosystems; major ecological and hydrological units can be discerned; drainage patterns can be delineated. These last two points are particularly relevant in The Netherlands, where water is a design tool of prime importance. DISCUSSION
AND CONCLUSIONS
The approach described in this article could only lead to the desired result if the following requirements are met: ( 1) The search for new quality in the landscape must be based on regional plans that pay equal attention to the economic, the ecological and the aesthetic aspects. (2 ) The analysis of landscapes should focus on those land use types that demonstrate the viability and strength to lead the way in the process of change. They can be seen as the driving force that can be exploited in the setting up of variables in planning models. (3) Land use types with a low degree of change over time should be linked and combined wherever possible, while the more dynamic forms of land use should be allowed a maximum of flexibility in the amount of space
213
REGIONAL PLANNING AS A STRATEGY
they want to use. This implies a separation of the two (Kerkstra and Vrijlandt, 1988). (4) Agricultural land use should primarily be located in areas with a potential for further development (Mentink, 1987). Areas with natural limitations for agricultural production should be identified. These are mostly the locations where stepped up production would require large investments, and farmers could not survive in the long run if left unaided. This land could be used better to locate the low dynamic framework. (5 ) Large expanses covered by nature areas and forests may form the basis from which the low dynamic network of zones is developed. This allows for a maximum profit of what nature has already invested over a long period of time in these areas (Bruin et al., 1987). (6 ) Design proposals at the regional level will have to comply with criteria set by long term management and control. The landscape must be under control in the ecological sense in order to survive for a long period, and be manageable from a financial point of view, which means that costs and gains should be more or less balanced. In order to achieve ecological stability the bio-geographical foundations of the landscape must be taken into account. In The Netherlands this means paying special attention to the hydrological situation. This will help in deciding on the most appropriate location of the framework and its detailing, and making use of the combined potentials of the abiotic substrate and the present land use.
(7) Land use types within the low dynamic part of the framework should be combined and integrated in order to function properly. The following combinations would be feasible: - water retention + nature development; - water quality management + nature; - forestry + nature; - forestry+ recreation. In other words, in looking for possibilities for natural development it is wise to try and find a combination with some other use, thereby fulfilling different needs of society simultaneously in the same place. In this way a generally accepted “slowly turning wheel” can be given form. Natural water purification systems such as helophyte filters could be seen as the “hedgerows” of the 2 1st century: they are new and necessary functional components of the contemporary landscape and can simultaneously full3 an ecological function.
REFERENCES Bruin, D. de, Hamhuis, D., Nieuwenhuijze, L. van, Overmars, W., Sijmons, D. and Vera, F., 1987. Ooievaar; de toekomst van het rivierengebied. Stichting Gelderse Milieufederatie, Arnhem. Kerkstra, K. and Vrijlandt, P., 1988. Het landschap van de zandgebieden; probleemverkenning en oplossingsrichting. Directie Bos- en Landschapsbouw, Ministerie van Landbouw en Visserij, Utrecht en Vakgroep Landschapsarchitectuur Landbouwuniversiteit Wageningen. Mentink, H.R.M., 1987. De landbouw naar 2050. In: Cammen, H. van der, Nieuw Nederland. Achtergronden. Stichting Nederland Nu Als Ontwerp. Staatsuitgeverij, s’cravenhage, pp. 151-155.
265
Regional Planning as a Strategy
D. SIJMONS State Forest Service, Utrecht (The Netherlands) (Accepted for publication 22 August 1989 )
ABSTRACT Sijmons, D., 1990. Regional planning as a strategy. Landscape Urban Plann., 18: 265273. In landscape planning the emphasis up till now has been predominantly on the preservation of historic values. A shift in attention to the moulding of new landscapes requires focusing on the analysis of elements and forces that underlie the formation of the existing landscapes and also an understanding of their potential for
future development. This new course must be taken for the sake offuture rural landscapes. In view of the uncertain developments in future land use the new landscapes need to be planned in a flexible way, allowing for dynamic development without damage to stable systems. This sort ofplanning is most viable when prepared and implemented at a regional level.
INTRODUCTION The modernization and industrialization of agriculture is the driving force behind the process of change in rural landscapes. One could say that agriculture in The Netherlands, when seen in a rosy perspective, is a highly successful branch of industry that has succeeded in creating a spectacular rise in productivity in a very short time. All this, of course, has been accompanied by negative environmental effects. This impact on the environment is as yet only partly visible in the decrease of differentiation in species, both in flora and fauna. The other effect is at the moment still invis0169-2046/90/$03.50
0 1990 Elsevier Science Publishers B.V.
ible: the ticking time bomb of the percolating nitrates and heavy metals into the subsoil, on their way to our fresh water resources. The intensification of agriculture and the accompanying improvements in the external production system was followed by a dynamic change in the layout of the land. This implies a fading away of the original identity of various manmade landscapes. Relations between landscape units are disappearing and only remnants of the once coherent patterns survive. The tendency towards more uniformity is caused by developments in rural engineering and in breeding techniques. Conditions in which everything can happen everywhere are
Fig. I. First stage of a dynamic landscape development in an agricultural area in the Eastern part of The Netherlands (Achterhoek). of 1862, the original scale was I : 50 000. Black dots are forests. the grey tone is “waste land”. Source: Topografische Dienst. Delft.
Topographic map
REGIONAL PLANNING AS A STRATEGY
267
Fig. 3. Third stage of development Topogratische Dienst, Delft.
of the same area shown in previous figures. The situation in 1952, the original scale of the map was 1: 25 000. Source:
REGIONAL PLANNING AS A STRATEGY
269
270
approaching, The variety in soil conditions for instance has partly lost its differentiating effect. A planning methodology should be devised for a modernization of our cultural landscapes that reintroduces a unified way of dealing with the process of change and development. PHYSICAL CHANGE
OF LANDSCAPES
The call for better planning is not a new one in The Netherlands: back in the 1960s policies were developed to modify or call to a halt the developments that lead to environmental degradation. In some areas physical planning agencies tried to regulate this process by setting up guidelines that would stipulate the degree, the way and the scale in which agricultural and natural land use types should be mixed. The nature conservation agency has converted this policy into measures that enable farmers to sign contracts stipulating a form of farm management in which for instance the disturbance of birds’ nests is prevented and the maintenance of non-functional hedges and tree stands is assured. Finally, landscape planners have tried to fit socioeconomic developments into the fabric of the existing landscape. Where this proved to be impossible it was attempted to fit in new developments in such a way that the outcome somewhat resembled the historical landscape (Figs. l-4). THE REMEDY FOR LANDSCAPE PLANNING
This analysis leads to the inevitable and painful conclusion that all these efforts, based on good intentions, accompanied by lengthy consultations and procedures, and costing large amounts of money, have not led to satisfactory solutions. In analysing the situation more closely, we must conclude that for the major part of the rural landscape the guiding planning policies of the past and their familiar strategies trying to Iit the new into the existing, or to make the
“modern” look like the “old and familiar” are no longer realistic. This is so for the simple reason that the historical identity of places and patterns has dissolved so much that we cannot find enough points of reference on which to base our prospects for the future. If we reject a historicizing approach to the planning of rural areas we must focus our attention on those patterns and processes that are the formative elements to be used in moulding new landscapes. By exploiting these elements we should be able to create an attractive and viable landscape. How should this new and demanding task be tackled? There is an urgent need to formulate a new course of action. We must recognize that the creation of new landscapes cannot be left to the free interplay of social and economic factors. Planning is needed. But our policy makers have not demonstrated a great deal of interest in problems such as the loss of identity of landscapes. This is not an issue of political concern and will never be the dominant argument for action in this respect. An attempt to plot out a new course is based on the following general considerations: - When the impending loss of the identity of the landscape is not a political issue the action of both the policy makers and the planning bureaucracy will normally be spurred by the needs and claims of various land use types and their mutual conflicts, or a misfit between land use and existing physiographic conditions. - A new course of action must be based on a consensus about quality requirements. Future landscape quality will depend on the possibility to create a new coherence among economic, ecological and aesthetic qualities. - Planning and management actions should be coordinated in a better way. This consideration is linked to the notion that highly praised qualities of the now disappearing historic landscapes can be attributed to the continuity and unity of both management
REGIONAL PLANNING
AS A STRATEGY
controls and land use types over a long period of time. The highly valued differentiation in landscape types can be seen as the product of deviations from the main course of development caused by circumstances in specific locations during certain periods of time. - With these considerations in mind an effort is currently being made in landscape planning in The Netherlands to develop new design strategies that offer alternatives to the prevailing approach which is unable to solve the existing tension between claims arising from the needs of agricultural production and those of nature conservation. A NEW STRATEGY FOR REGIONAL PLANNING AND DESIGN
On the basis of the previous discussion we can distinguish two key factors: - how to deal with the factor “time”; - how to deal with the issue of “uncertainty”. The planning and design of new landscapes involve, among other things, the manipulation of living material. Here, the factor of time is of prime importance. It is one that can never be manipulated by man. Nature has invested much time in existing forest land, in hedgerows, and even more so in certain ecosystems as well as in soil formation processes. When locating new woodlands, greenbelts and nature development projects, one must always take into account the fact that nature is the main contractor and should be given ample time to do its job. This is not a easy condition to full3 within the standard short term planning periods adopted in conventional physical planning procedures. One must bear in mind that even the so-called “temporary” tree stands, such as poplar timber for the paper industry, need three consecutive planning periods to mature. An important conclusion is that some land use types in rural areas apparently need a high degree of stability in space and time, and do
271
not permit a major disturbance in external conditions. These types of land use are: - Nature conservation and development; - Forestry and woodlands; - Hedgerows and tree plantings; - Fresh water retention and supply; and derived from these, to a certain degree: - extensive forms of outdoor recreation - certain types of low input farming. In view of their needs these land use types can be designated metaphorically as “the slow turning wheels”in the landscape. The planning and design problem here is to develop a strategy warranting the survival of “low dynamic” land use types by not letting them be overrun by extreme dynamic land use: the “j&t turning wheels” in the landscape, such as agriculture and urban activities. This brings us to the second issue: dealing with uncertainty. It has proved to be extremely difficult to predict the direction of dynamic processes within certain land use types. In looking back at, for instance, post-war developments in agriculture we see several moments when forecasts were made about its prospects. We can now conclude that all these forecasts have misjudged some essential aspects and have proved to be inaccurate. It is impossible and even undesirable to try and predict technological development in agriculture and combine these predictions with attempts to slow down or prevent this. Technological innovation in the future will continue to offer spectacular opportunities for the agricultural entrepreneur to increase productivity and to reduce costs. Every decision to invest or de-invest will eventually be made and implemented at the level of the individual agricultural enterprise and it is therefore very difficult to predict developments and their visual and ecological impact. The same goes for the forecasting of government measures to improve external conditions for production. Predicting the future will become even more haz-
272
ardous if one takes into account the possibility of the so-called “trend breaks”. Trend breaks may have various origins: - Agriculture is at the moment surpassing the carrying capacity of the natural environment. In some places the very survival of agriculture itself is at stake, especially where soil quality is deteriorating. Counter measures are required to stop this process. - Agricultural production in the whole of Europe must adapt to the rules of an open market. The issue of over-production may be solved in various ways, such as a drastic reorganization, the imposition of quotas, the extensification of production, set-aside programmes, etc. One can distinguish a rupture between the period when a raise in production was the central objective and the new era where both makers and private enterprise look upon the lowering of production costs as a primary goal. - A shift in consumer needs can be observed at the moment: from quantity to quality of products and to a greater variation in types of product. Agriculture will have to meet this challenge in an adequate way. The uncertainties caused by these trend breaks cannot be reduced by an increased research effort or better judgement on the part of planners. We will have to learn and live with uncertainty. The only certainty might well be change itself. The consequence for landscape planners is to set up plans that incorporate a marked degree of flexibility. Flexibility can only be achieved by the demarcation of areas for agricultural use and by setting up a structural framework in between and around these areas that does not collapse whenever developments in agriculture change in scope and direction. This implies a separation in space of those land use types that are in conflict in terms of pace of development, and the use of design models for agricultural land use that can absorb a broad range of types of development. In many cases this will come down to a
D. SIJMONS
search for a layout with stable configurations in the form of interconnected zones containing those land use types that depend on a low degree of dynamism. These zones form a body, or framework, enveloping types of land use that demonstrate a high degree of dynamism. The framework is more or less independent of the dynamic areas it encloses and agriculture can be offered a wide array of developments as long as it stays within the limits of the environmental boundaries. This type of strategic planning is most effective when applied at a regional level of scale, because: complete landscape units can be taken into account; nature development can be analysed at the level of interrelated ecosystems; major ecological and hydrological units can be discerned; drainage patterns can be delineated. These last two points are particularly relevant in The Netherlands, where water is a design tool of prime importance. DISCUSSION
AND CONCLUSIONS
The approach described in this article could only lead to the desired result if the following requirements are met: ( 1) The search for new quality in the landscape must be based on regional plans that pay equal attention to the economic, the ecological and the aesthetic aspects. (2 ) The analysis of landscapes should focus on those land use types that demonstrate the viability and strength to lead the way in the process of change. They can be seen as the driving force that can be exploited in the setting up of variables in planning models. (3) Land use types with a low degree of change over time should be linked and combined wherever possible, while the more dynamic forms of land use should be allowed a maximum of flexibility in the amount of space
213
REGIONAL PLANNING AS A STRATEGY
they want to use. This implies a separation of the two (Kerkstra and Vrijlandt, 1988). (4) Agricultural land use should primarily be located in areas with a potential for further development (Mentink, 1987). Areas with natural limitations for agricultural production should be identified. These are mostly the locations where stepped up production would require large investments, and farmers could not survive in the long run if left unaided. This land could be used better to locate the low dynamic framework. (5 ) Large expanses covered by nature areas and forests may form the basis from which the low dynamic network of zones is developed. This allows for a maximum profit of what nature has already invested over a long period of time in these areas (Bruin et al., 1987). (6 ) Design proposals at the regional level will have to comply with criteria set by long term management and control. The landscape must be under control in the ecological sense in order to survive for a long period, and be manageable from a financial point of view, which means that costs and gains should be more or less balanced. In order to achieve ecological stability the bio-geographical foundations of the landscape must be taken into account. In The Netherlands this means paying special attention to the hydrological situation. This will help in deciding on the most appropriate location of the framework and its detailing, and making use of the combined potentials of the abiotic substrate and the present land use.
(7) Land use types within the low dynamic part of the framework should be combined and integrated in order to function properly. The following combinations would be feasible: - water retention + nature development; - water quality management + nature; - forestry + nature; - forestry+ recreation. In other words, in looking for possibilities for natural development it is wise to try and find a combination with some other use, thereby fulfilling different needs of society simultaneously in the same place. In this way a generally accepted “slowly turning wheel” can be given form. Natural water purification systems such as helophyte filters could be seen as the “hedgerows” of the 2 1st century: they are new and necessary functional components of the contemporary landscape and can simultaneously full3 an ecological function.
REFERENCES Bruin, D. de, Hamhuis, D., Nieuwenhuijze, L. van, Overmars, W., Sijmons, D. and Vera, F., 1987. Ooievaar; de toekomst van het rivierengebied. Stichting Gelderse Milieufederatie, Arnhem. Kerkstra, K. and Vrijlandt, P., 1988. Het landschap van de zandgebieden; probleemverkenning en oplossingsrichting. Directie Bos- en Landschapsbouw, Ministerie van Landbouw en Visserij, Utrecht en Vakgroep Landschapsarchitectuur Landbouwuniversiteit Wageningen. Mentink, H.R.M., 1987. De landbouw naar 2050. In: Cammen, H. van der, Nieuw Nederland. Achtergronden. Stichting Nederland Nu Als Ontwerp. Staatsuitgeverij, s’cravenhage, pp. 151-155.