Sustainable Cycles of Policies
Crop Rotation as a Metaphor
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Annex 2 of Reordering
Networks of Incommensurable Concepts in Phased Cycles
and their comprehension through metaphor
In searching for appropriate metaphors to illustrate the need for cycles of
policies there is a certain appropriateness to using a process which has traditionally
been considered basic to sustaining the productivity of the land, namely crop
rotation. The rotation of agricultural crops is an interesting 'earthy'
practice to explore in the light of the mind-set which it has required of farmers
for several thousand years.
Crop rotation is the alternation of different crops in the same field in some
(more or less) regular sequence. It differs from the haphazard change of crops
from time to time, in that a deliberately chosen set of crops is grown in succession
in cycles over a period of years. Rotations may be of any length, being dependent
on soil, climate, and crop. They are commonly of 3 to 7 years duration, usually
with 4 crops (some of which may be grown twice in succession). The different
crop rotations on each of the fields of the set making up the farm as a whole
constitute a 'crop rotation system' when integrated optimally. Long
before crop rotation became a science, practice demonstrated that crop yields
decline if the same crop is grown continuously in the same place. There are
therefore many benefits, both direct and indirect to be obtained from good rotational
cycles (38, pp. 170-8):
(a) Control of pests: with each crop grown the emergence of characteristic
weeds, insects and diseases is facilitated. Changing to another crop inhibits
the spread of such pests which would otherwise become uncontrollable (to the
point that some crops should not be grown twice in succession). By rotating
winter and summer crops, the farmer fights summer weeds in the winter crop
and winter weeds in the summer crop.
(b) Maintenance of organic matter: some crops deplete the organic
matter in the soil, other increase it.
(c) Maintenance of soil nitrogen supply: no single cropping system
will ordinarily maintain the nitrogen supply unless leguminous crops are alternated
(d) Economy of labour: several crops may be grown in succession with
only one soil preparation (ploughing). For example: the land is ploughed for
maize, the maize stubble is disked for wheat, then grass and clover are seeded
in the wheat.
(e) Protection of soil: it was once believed necessary to leave land
fallow for part of the cycle. Now it is known that a proper rotation of crops,
with due attention to maintaining the balance of nutrients, is more successful
than leaving the land bare and exposed to leaching and erosion.
(f) Complete use of soil: by alternation between deep and shallow-rooted
crops the soil may be utilized more completely.
(g) Balanced use of plant nutrients: when appropriately alternated,
crops reduce the different nutrient materials of the soil in more desirable
(h) Orderly farming: work is more evenly distributed throughout the
year. The farm layout is usually simplified and costs of production are reduced.
The rushed work characteristic of haphazard cropping is avoided.
(i) Risk reduction: risks are distributed among several crops as
a guarantee against complete failure.
The situation is somewhat different in the case of single-species forests
where 'rotation' is the guiding principle in the special sense of
the economic age to which each crop can be grown before it is succeeded by the
next one. (For example, on a 100-year rotation required for oak, one per cent
of the forest would be clear cut each year, and a further 20 percent thinned
out). In total contrast to crop rotation is the 'monoculture' cropping
system in which the same crop is grown every year. This is possible on a large
scale only by the heavy application of chemical fertilizers, herbicides and
pesticides. It leads to long-term problems of soil structure and erosion, as
well as to the accumulation of pollutants.
Because of the short-term advantages of fertilizers, efforts to design new
approaches to crop rotation have been limited. It is only with the resurgence
of interest in non-exploitive, non-polluting agriculture that such possibilities
are being investigated (39). From an agronomist's perspective, the problem is
to strike a balance between harmonizing the three-fold soil-plant-climate relationship
and those of the economic constraints of production. Because such threefold
relationships are now fairly well understood, rotation cycles can now be considered
as a whole in which the order and the plants used are of secondary importance.
The problem is to ensure that the soil-plant-climate relationship is in an optimally
balanced state at every moment in order to become increasingly independent of
its past. The production constraints complicate this evolution and the choices
possible, especially when requirements change rapidly without taking into account
the recent history of a crop rotation (39).
There is a striking parallel between the rotation of crops and the succession
of (governmental) policies applied in a society. The contrast is also striking
because of the essentially haphazard switch between 'right' and 'left'
policies. There is little explicit awareness of the need for any rotation to
correct for negative consequences ('pests') encouraged by each and
to replenish the resources of society ('nutrients', 'soil structure')
which each policy so characteristically depeletes.
There is no awareness, for example, of the number of distinct policies or
modes of organization through which it is useful to rotate. Nor is it known
how many such distinct cycles are necessary for an optimally integrated world
society in which the temporary failure of one paradigm or mode of organization,
due to adverse circumstances (disaster) is compensated by the success of others.
It is also interesting that during a period of increasing complaints regarding
cultural homogenization ('monoculture'), voters are either confronted
with single-party systems or are frustrated by the lack of real choice between
the alternatives offered. There is something to be learnt from the mind-sets
and social organizations associated with the stages in the history of crop rotation
which evolved, beyond the slash-and-burn stage, through a 2-year crop-fallow
rotation, to more complex 3 and 4-year rotations. Given the widespread sense
of increasing impoverishment of the quality-of-life, consideration of crop rotation
may clarify ways of thinking about what is being depleted, how to counteract
this process, and the nature of the resources that are so vainly (and expensively)
used as 'fertilizer' and 'pesticide' to keep the system
going in the short-term. The 'yield' to be maximized is presumably
human and social development.