What is the Link between Environmental Issues and
Agronomy?
What is the link between environmental issues and agronomy?
The authors, who are both agronomists, comment a paper by Marc Benoît and François Papy titled "a situational analysis of the role of agronomy in environmental issues" (Dossier de l'environnement de l'INRA n°17, Sciences de la société et environnement à l'INRA - matériaux pour un débat (1).
[R] What is the link between environmental issues and agronomy?
From an etymological point of view, the term agronomy refers to the laws regulating crop field management. Far from being a simple scientific subject, agronomy is above all an art and a practice (just as medicine is) and aims at using the above-mentioned laws. Agronomy is considered a scientific discipline in the core of an applied research institutes, such as INRA (French National Institute for Agricultural Research), and is defined by its "object" of research: the problems raised by crop fields management. The aim is not to establish a collection of data on crop field management, but to establish "a constant explanatory and predictive link between cultural operations and the criteria that sanctions plant production activity: quantity and quality of harvested products, production costs, effects on cultivated areas and the environment"(J. Boiffin and G. Lemaire, 1992).
For a long time, agronomy mainly "ignored" the effects of crop management on the environment and far too extensively privileged the study of quantitative production and of its direct economic consequences on farms, yet the current demands of society imply a more balanced and comprehensive taking into account of the crop management effects on the different target variables. This approach to agronomy is more comprehensive and systemic and does not question the general definition of the discipline. However, the widening to clearly defined environmental issues implies considering the input (crop management modalities) and output variables (effects on the crop environment and on the environment in general) of vaster spatial and temporal entities than simple "farm fields" or "crop rotations"; in the past, agronomy was practically exclusively concerned by these entities.
The environment which is at stake here, is that of Man. In English, the term "environment" defines both the environment in which a crop or the Environment evolves, in general; we consider that "environment" cannot be reduced to the former definition and must always be extended to the latter. Agronomy must take into account an environment very different from its traditional research subject, with distant spatial and temporal features: atmospheric deposits in mountain forests, pollution and changes in aquatic environments, quality of underground water, evolution of the atmospheric composition, ecotoxicity of food chains, modification of biodiversity in ecosystems, diffusion of transgenes in natural populations, etc.
Agronomy must moreover take into consideration the effects of sources of pollution that may be generated outside of its traditional field of research and for which agriculture is both a receptacle and regulator: recycling of urban or industrial waste, interactions with urban atmospheric pollution.
The activity of an agronomist involved in environmental issues thus implies
going backwards and forwards between two levels of study: that of the farm
field, the elementary spatial entity where cultural operations are implemented,
and that of vaster spatial entities, which play a functional role in the
field of environmental issues: watersheds, industrial waste infiltration
basins, periurban areas, areas protected by environmental regulations or
areas with poorly defined borders that are affected by the diffusion of chemicals
or the constant move of living organisms. Agronomists cannot specialise in
crop field management without the help of "farm management" specialists and,
so as to understand the environmental variables to be considered, they must
join forces with specialists who understand the functioning of different
spatial entities. Agronomy is thus at the crossroads of two fields of activity
that identify and formalise the two constraints hanging over crop field
management: production constraints and their economic sanctions and environmental
constraints. The objective of agronomy is to create and evaluate certain
agricultural practices (cultural operations, crop management itineraries,
crop systems), as well as their spatial arrangement, that take into consideration
these two constraints and conciliate sometimes contradictory objectives.
At the interface of production and environmental issues, different axes of
integrated research stem from this general objective and are now amongst
the priorities of INRA's Environment and Agronomy Department:
Environmental assessment of crop systems
In the framework of the "life cycle analysis" carried out in industries,
both the evaluation of the crop production environmental impact and the
comparison of crop systems or commodity sectors must take into account all
the environmental parameters likely to be affected and the possibility of
pollution transfers between the different stages of the life of products
(production, use, destruction or recycling) or the different environments
(soil, water, air).
Settling of innovative crop systems, respectful of complex
specifications
In certain cases, conciliating agricultural competition and environmental
protection is extremely challenging. In fact, there is no general solution
to the problem: farmers and development agents must be given the means to
adapt production methods to the diversity of pedoclimatic conditions, market
demands and regulations.
Mastering of the crop systems spatial organisation
The spatial organisation of crops and crop successions depend on the individual
choices of farmers, who do not generally consult each other: this results
in uncontrolled erosion effects, propagation of funghal diseases and will
soon lead to the propagation of transgenes. In order to identify the key
points of the spatial organisation of crop systems subject to consultations
or regulations, we need to have a better knowledge of the water flows, mineral
elements and living organisms in crop fields, as well as of the consequences
of production methods on these flows.
Evaluation of the environmental impact of statutory texts
To estimate the consequences of a regulation, the economic approach alone
cannot infer the relationship between production and techniques applied to
the environment. One of the essential stakes of research is the association
of the agronomic models that account for the effects of these techniques
on production and the environment and the economic models that account for
the behaviour of agents in a given statutory context.
In this context, the further development of knowledge in the field of cultivated
plant populations , soil and atmosphere, all major functional entities, is
essential and must be oriented and organised so as to account - as constantly
and explanatorily as possible - for the effects of cultural operations on
agricultural production but also on relevant environmental variables. It
is thus an extremely different point of view from that which sometimes prevailed
in the past, when agronomy was restrained to using knowledge acquired by
other disciplines. The main aim is to explicitly consider cultural operations
in all studies relative to the different functional entities. To this effect,
the three departments constituting the former Physical Environment and Agronomy
sector are now associated in INRA's new Environment and Agronomy Research
Department.
Such an objective implies that a large place must be assigned to modelling
methodology; this is implemented in three different ways:
- conceptual modelling which allows to organise our knowledge on the functioning
of different entities (plants, crops, soils, hydrological systems, atmosphere,
etc.) so as to explain the multiple effects that stem from cultural operations
and crop field management modes. This approach to modelling must enable us
to identify and hierarchically classify the most relevant functions and
interactions, as well as our lack of knowledge in certain areas, so as to
reach a satisfactory analysis of the functioning of crop fields and crop
systems.
- predictive modelling of the functioning of crop fields and crop systems
which enables us to simulate and quantify both the levels of agricultural
production (in quantity and quality), established through the implementation
of various crop management methods, and the foreseeable environmental impacts.
Economic and environmental risks must be quantified, taking into account
the spatio-temporal variability of physical environment constraints, the
socio-economic risks and uncertainties linked to the failures of the model.
- decision support modelling. The aim is no longer to simultaneously assess
or predict agronomic and environmental outputs resulting from agricultural
practices, but to design and assess the decision-making rules that allow
the implementation of logical and coordinated sequences of cultural operations,
the objective being to satisfy "economic" and "environmental" specifications.
Simulation enables us, at a low cost, to explore new solutions and to conciliate
economic and environmental objectives sometimes first considered to be
irreconcilable.
Therefore, the "Fisher" experiment, which used to be considered as a privileged
tool of agronomy, is more and more frequently used in modelling. It is expected
to support the formalisation of conceptual models and the estimation of the
parameters of predictive and decision-making support models. On-site approaches
are actually less exclusively centred on experimentation: analyses focus
increasingly on the agricultural field (diagnosis-survey); this is the only
way to hierarchically classify determining factors determining the crop systems
impact on the environment and to define the limits within which their effects
should be modelled. In a complementary way, experiments carried out at a
local level and on-site studies remain absolutely necessary to validate these
models.
These experiments and on-site studies are articulated in such a way as to
take account of the problem complexity, owing to the link between our knowledge
of physico-chemical or biological processes and of technical acts. By opening
the black boxes we can enrich the range of solutions: thus if we attribute
a type of ground pollution to a certain crop, the only solution is to change
the crop rotation, which often entails economic or organisational problems
for the farmer; by identifying the technique, the interaction between technics
and physics that is at the base of this problem, we can try to solve it by
adjusting the crop management or crop location without eliminating it altogether.
Therefore, the development of environmental issues follows, enriches and
accelerates the renewal of agronomical methods as well as the issues studied
by agronomy.
This article is taken from the "Dossier de l'environnement de l'INRA,
n°17", by G. Lemaire and J.-M. Meynard.
Translated from French by Nicole Scott.
Note
(1) Vilotte O., Barrès D., (dir.) 1998. Sciences de
la société et environnement à l'INRA - matériaux
pour un débat. [Dossier de l'environnement de l'INRA n°17, 105
p.] On line: www.inra.fr/dpenv/do17.htm [VU]
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