Below is presented the kinds of decisions a farm household can make (FAO, 1990). In farming-systems analysis it is important to know the degree of freedom the farm household has in making decisions. What factors affect the sustainability of farming systems? And how does one find ways to create sustainable farming systems in the CEECs? This section aims at covering these two questions.

All of the decisions in Table 1 are made by the farm-household. It is, therefore, important to consider them all when deliberating sustainability issues.

While identifying factors affecting sustainability, it may be good to recall the various dimensions of the sustainability concept: sustainability includes not only the environmental dimension but also the economic and social dimensions. This is implicitly clear from Table 1. However, some quantifiable measures are needed to check whether a farming system is sustainable or not.

Table 1: What decisions farmers have to make in the medium term (FAO, 1990, 22-23).

As noted in the preceding section, McConell and Dillon (FAO, 1997) presented eight system properties and the criteria for measurement of performance, making a quantification on farm level or on farm and social level possible. The properties are summarized in Table 2.

Table 2 could serve as an example for how the economic and social sustainability factors can be "operationalized". Regarding the CEECs, it would probably be possible to make such tables for each region concerned. One could add a ninth property, equitability. This would imply that the system is socially acceptable in term of income distribution and ownership (no strong polarization). The equality of income distribution can be measured by the Gini coefficient or the Lorenz curve applied in general economics.

Table 2: System properties and indicators for measurement of performance (FAO, 1997)

Sustainable agriculture implies that yields do not decline over time, while the destruction of natural resource capital is avoided. In some cases, the increased intensity of agriculture may have negative effects on the environment. The opposite may also be unsustainable if nutrient depletion leads to impoverishment of the soil. In many CEEC cases, sustainability may be prevented by an intensity in inputs that is too low, or the soil is depleted from nutrients, particularly potassium (K) (Andres, 1996). It is also important to maintain the remaining HNV farming systems, which are of high environmental and amenity value in the CEECs. In the long run, these areas may be very valuable. Some of them may otherwise be lost in the transition process.

Helenius has presented a checklist for ecological sustainability in the use of farmland (Helenius, 1999A, 1999B). He has identified two key issues: protection of the environment and maintenance of the resource base. The checklist is presented below in tabular form in Table 3.

Table 3: Checklist for "operationalizing" ecological sustainability in agriculture: a natural science point of view, which on its own is not sufficient for sustainability research (Helenius, 1999 B)

The term, environmental conservation, means the saving of biodiversity in terms of the genetic richness of populations, the species richness of communities, and the habitat or ecosystem richness of landscapes. The desired function of protecting landscapes is partly to maintain the habitats for species, but also the amenity, aesthetic and cultural value of the landscape. Preventing the loading of nutrients is important (Helenius, 1999A).

The main causes for surface waters being loaded with nutrients are primarily the emissions of phosphorus both in the surface runoff water and attached to the sediments from erosion. The phosphorus (P) and nitrogen (N) nutrients derive from slurry, solid and liquid manure, chemical fertilizers and, to a certain extent, natural leaching independent of human activity. The consequences of this loading may be: an increased turbidity of the water and an accelerated eutrophication. These results may subsequently lead to an increase in undesirable biological productivity, changes in the composition of plant species and changes in the fish species and the stock of fishes. As a consequence, the recreational use of the lakes affected will diminish. Nitrate leaching may increase the nitrate content in ground water and drinking water. This has been a common problem in Western Europe, whereas the fertilizing intensity in most of the CEECs has declined during the transition period. Consequently, nutrient leaching is not a problem everywhere. However, increasing intensity levels in some countries show that nutrient leaching may increase in some countries. Poland, the Czech Republic and Romania have problems with water pollution in connection with agriculture (FAO, 1999A). Leaching is affected by a number of farm management practices.

The sustainable use of natural resources comprises many points. Energy in agriculture and renewal of energy sources are issues of sustainability. In West European agriculture the increased use of non-renewable support energy for crop production has decreased energy efficiency. Energy crops have been suggested as a possible research area for alternative energy sources (Helenius, 1999 a). In many of the CEECs, agriculture is likely to be less energy intensive than West European agriculture.

Mismanagement of agricultural soil and its fertility results in erosion, salinization and desertification. Soil can also become contaminated with chemicals. For instance, in Poland, the Czech Republic and Romania soil degradation and soil erosion are seen as major environmental problems (FAO, 1999A). Biological diversity in the soil is not fully understood yet (Helenius 1999A). Heavy metals in the soil (e.g. as a consequence of impurities, like cadmium, in fertilizers) will also affect soil sustainability in the long run.

Sustainable farming systems should take the effects on the atmosphere into account. Agriculture has a double role here since it works as a sink of carbon dioxide (CO2), but is an emitter of methane (CH4) and nitrous oxide (N2O). Volatilization of ammonia is a source of acid rains. Especially high animal stocking densities may be a reason of ammonia emissions. Stocking density is also significant in determining grazing pressure. Several factors, however, must be taken into account when referring to stocking densities, such as (a) how the foraged area is managed and what the soil type is and (b) whether the grazing of unimproved grass-land is sustainable or not. The distribution of livestock over time is also another important factor. (Baldock and Beaufoy, 1993). Traditional farming systems using transhumance have tried to resolve the pressure by moving their cattle to other areas, for instance, during dry periods or during warmer periods.

Biological diversity in its various forms needs to be preserved. Helenius cites an FAO estimate, according to which 75 percent of the genetic diversity in agricultural crops has disappeared in the past hundred years (Helenius, 1999A). The loss of heritage from former eras is considered to be a main environmental problem in Latvia (FAO, 1999A).

In summary, the above-mentioned factors in farming systems that affect ecological sustainability include:

• pollution of surface and ground waters because of a too intense fertilizer utilization, wrong management practices, or stocking densities that are too high;
• high volatilization of ammonia from animal herds;
• soil degradation and loss of soil;
• increased amounts of heavy metals in soils;
• decline in the number of plant and animal species, including wildlife species and habitats;
• increased air pollution affecting agriculture adversely;
• effects on the visual landscape and loss of cultural heritage;
• contamination of the environment by pesticides.

• Diversity of crop species to enhance the farm’s biological and economic stability that is created, for example, through rotations, relay cropping and intercropping;
• Selection of crop varieties and livestock that are well suited to the farm’s soil and climate and that resist pest and disease;
• Preference for farm-generated resources over purchased materials, as well as for locally available off-farm inputs (when required) over those from remote regions;
• Tightening of nutrient cycles to minimize loss of nutrients off the farm, realized, for example, by composting livestock manure or by rotating using legumes to fix nitrogen;
• Livestock housed and grazed at low density, with a preference for high-roughage rations over concentrated feeds for ruminants, and herd-size scaled to the farm's ability to produce feeds and use livestock manure efficiently;
• Enhancement of the soil's ability to take up applied nutrients for later release as needed by the crop, in contrast to direct uptake by the crop at the time of application;
• Maintenance of the protective cover on the soil throughout the year, through tillage that leaves crop residues on the surface, and through cover crops and living mulches;
• Rotations that include deep-rooted crops to tap nutrients reserves in lower strata and that control weeds by alternating between cool season and warm season crops;
• Use of soluble inorganic fertilizers, if at all, only at a level that the crop can use efficiently, and use of these materials only in case livestock manure and legumes cannot cover nutrient deficits;
• Enhancement of conditions for controlling or suppressing weeds, insect pests, and diseases; if synthetic insecticides and herbicides are used at all, they should be used only as a last resort and only when there is a clear threat to the crop.

By using good agricultural practices, negative environmental impacts of farming systems can be reduced, excessive amounts of leaching can be avoided, ammonia volatilization can be reduced and pesticide losses can be minimized.

What are good agricultural practices from a sustainability point of view depends partly on local conditions. In order to exemplify such practices, the following list (applicable to northern Europe) compiled by Seppänen and Korkman et al. is presented (Seppänen, 1999; Korkman et al., 1993):

1. Cultivation planning and monitoring.

An annual, appropriate cultivation plan for the whole farm is made. Measures carried out on each parcel are recorded, including nutrient inputs amounts. Results from soil analysis are included in the plan.
 
2. Fertilizer and pesticide use.

The appropriate amounts of nitrogen, phosphorus and pesticides vary greatly depending on the productive potential of soil.
 
3. Headland and filter strips.

Buffers zones, filter strips and headlines are left next to waterways to prevent soil, nutrients and other substances from leaching out of arable fields into surface water.
 
4. Plant cover outside the growing season.

Fields are covered with plants in the wintertime to reduce nutrient leakage.
 
5. Reduced tillage.

If no plant cover is used, autumn ploughing can be replaced by direct sowing, stubble cultivation or spring ploughing.
 
6. Stocking densities.

It is somewhat difficult to generalize what should be considered maximum stocking densities, depending on the agroecological system in question (for examples, see Baldock and Beaufoy 1993, p. 30-31). Pork and poultry production tends to be intensive and less sustainable than cattle or sheep production. However, good agricultural practices require not using livestock densities above a certain ceiling. In Finland this ceiling is defined as 1.5 LU/ha (Pirttijärvi et al., 1995).
 
7. Storage and application of manure.

Manure must be appropriately stored and ploughed into the field when spread and alternatively injected or placed under the soil in order to avoid ammonia losses.
 
8. Nature and landscape management.

Biodiversity as well as diversity in the landscape should be taken care of, and possible valuable habitats should be preserved or restored.

In summary, it is possible to use checklists in order to determine factors affecting the sustainability of farming systems. Two examples of such checklists have been presented in this section. The checklists can be used for identifying constraint on sustainability on a local or regional level. The checklists, while tentative, may function as a starting point for defining sustainability problems in selected CEECs. In the long run, sustainable farming in the CEECs will likely be based on so-called good agricultural practices. Examples of such practices have been given. More specific lists on a national level for the various CEECs may be formulated.