Organic agriculture in a closer sense pursues an organizational principle: to manage a mixed farm within a nearly closed system an organism alike. Since site conditions are individual properties by definition, a farm can be conceived as an individual entity. In comparison to mainstream agriculture, organic agriculture depends more on specific site conditions and is therefore forced to combine the best adapted elements to a holistic approach. If environments are dominated one-side by nature (and/or the market), farmers are forced to realize more simplified farming systems under the organic label, too. In central European conditions and humid temperate climate, the organic agriculture's relationship with environmental quality is enhanced by a mix of crop and livestock farming that creates diversified production systems.
Normally, arable farms can be transformed into mixed farms without difficulty. These farms can fulfil the organizational principle better via integrating livestock production which enables integration of arable fodder cropping and diversified rotations. To which extent these measures are able to regulate and stabilize the whole farming system depends on the special site conditions. Often this question can only be answered by using results of long-term experiments, if available. On the other hand, in fertile soils like black earth located in dry areas of Central Europe having less than 500 mm rainfall per year, unproductive loss of water caused by inefficient use of green manure has to be avoided particularly when it is not needed for stabilization of soil-fertility. However, main forage crops, such as lucerne with its potential to increase soil fertility, will consume high amounts of water, an effect which can cause a decreased positive pre-crop effect of this potentially valuable nitrogen fixing crop. Consequently, growth of perennial lucerne must optimize the production system in a continental climate.
Table 1. Potential nutrient imbalances of different organic farm types
Farm Types | ||||
Compensation of imbalances |
Dairy farm on grassland |
Arable farm without animals |
Vegetable growing |
Fruit growing farm |
Possible |
Nutrient surplus due to purchase of concentrates |
High nutrient deficiency due to export of products |
High nutrient deficiency due to export of products |
Nutrient deficiency due to export of products |
=> Export of manure |
=> Purchase of fertilizer / manure |
=> Purchase of fertilizer / manure |
=> Purchase of fertilizer / manure | |
Restricted or Impossible |
High emission of greenhouse gases |
Low diversity of crops |
High energy input |
High energy input Low diversity of crops Use of pesticides |
Potential imbalances of nutrients, especially nitrogen, in different farming types are listed in Table 1. Some of them can be compensated by export or purchase of manures and Fertilizers and by exchange between cooperating farms. In Northern parts of Europe but also in hilly and alpine regions, highly specialized animal farms are dominated by the site-conditions, e.g. permanent pasture that cannot be ploughed, lack of straw and high amounts of purchased nitrogen imported with feed stuffs. Permanent grass land and soil tranquillity are the main elements for stabilized agro-ecosystems, but due to frequently observed N-surplus in animal farms, definite or potential imbalances have to be equalized.
Another extreme showing similar conflicts is represented by highly specialized vegetable farms. Production of several leafy crops with short vegetation periods and fast development show high demand for nutrients. High soil fertility characterized by high soil organic matter content and high amounts of nutrients released, depends generally on purchased nutrients bound in organic manures from outside the farm and on an efficient irrigation system. To combine the one system having surplus of nutrients with the other having a lack of nutrients and a high demand for organic matter, is convincing but normally these farm types are not neighbour farms per se.
It is quite obvious that imbalances of nutrients (and energy) characterize the above- mentioned problems of farms operating under the dominating influence of the natural environment. To start with, analysis of energy and nutrient flows might open and widen our understanding for the organizational principle if farm borders were to be overcome and new system borders of cooperating farms or farm units were to be considered. In many cases it might be that farm gate balances and farm borders will not characterize and define the unit that should be under study, when keeping in mind the organizational principles for establishing a nearly closed farm organism or at least nearly closed nutrient flows.
A tool to optimize organic farming might be the so called eco-balance or life cycle assessment (LCA) (Figure 1). It includes a detailed analysis of several environmental impact categories and their related system of indicators within the set frame (Figure 2).
In a first step, the ecobalance should be limited to analysis of nutrient and energy flows only. In a second step, the method can be extended by further environmental impact categories such as biodiversity, water protection, soil protection, eutrophication, acidification of soils and global warming potentials, altogether often a direct function of the energy and nutrient imbalances described.
Further imbalances oriented on impact categories that might be compensated by cooperating farms are listed in Table 2. In contrast to effects on soil protection and resource depletion which can be evaluated by the farmers themselves, other imbalances can be analysed and compensated under expert guidance only. No compensation of imbalances by farm cooperation can be achieved as regards ecotoxicity, human toxicity and animal welfare.
Combining indicators and environmental quality targets is not only an instrument for environmental assessment in general, but might also help to describe and optimize process quality and quality assessment in organic agriculture in the future. We recently finished a process-life cycle assessment (ecobalances) comparing conventional and organic agriculture in an area of 7 000 ha in Hamburg, Germany (Geier et al., 1998; Geier & Köpke, 1998). In this study organic farming did show advantages in seven out of nine impact categories. For the aims of optimizing organic farming systems by overcoming the farm borders, we also consider ecobalance a feasible impact category.
Geiger, U. and U. Köpke (1998): "Comparison of conventional and organic farming by process-life cycle assessment. A case study of agriculture in Hamburg". In: Ceuterick, D. (Ed.): International Conference on Agriculture, Agro-Industry and Forestry. Proceedings 3-4 December 1998, Brussels, Belgium. 1998 PPE/R/161, 31-38 pp.
Geiger, U., Frieben, B., Haas, G., Molkenthin, V. and U. Köpke (1998): Ökobilanz Hamburger Landwirtschaft - Umweltrelevanz verschiedener Produktionsweisen, Handlungs-felder Hamburger Umweltpolitik. Schriftenreihe Institut für Organischen Landbau. Berlin: Verlag Dr. Köster, ISBN 3-89574-318-6.
Table 2. System of environmental indicators for farms, used in process-life cycle assessment (ecobalance)
Impact categories |
Compensation of imbalances by farm cooperation |
Indicators |
|
Biodiversity |
partly |
Grassland: |
|
Landscape |
partly |
Grassland: |
|
Soil protection* |
partly |
|
|
Drinking water protection |
yes |
|
|
Eutrophication |
yes |
|
|
Acidification |
yes |
|
|
Global warming potential |
partly |
|
|
Resource depletion* |
yes |
|
|
Ecotoxicity** |
no |
|
|
Human toxicity and ** |
no |
|
|
Smell |
yes |
|
|
Animal welfare** |
no |
|
|
Ozone depletion |
yes |
|
Impact categories not marked by asterisks: compensation of imbalances possible by using expert instructions
* Compensation can be performed by farmers themselves
** No compensation possible by farmer cooperation
Figure 1. Components of an ecobalance
Figure 2. Farm-borne impacts on environment
