«Measuring Agricultural Sustainability Chapter · September 2010 DOI: 10.1007/978-90-481-9513-8_2 CITATIONS READS 3 authors, including: Zahra Ranjbar ...»
4 Components of Sustainability Measurement System theory has proven valid for sustainability assessment. First, it contributes to clarifying the conditions of sustainability. By definition, system theory forces one to define the boundaries of the system under consideration and the hierarchy of aggregation levels. In agricultural land use systems the most relevant subsystems (or levels) are the cropping system (plot level); farming system (farm level); watershed/village (local level); and landscape/district (regional level). Higher levels (national, supranational, and global) influence agriculture more indirectly by policy decisions or large-scale environmental changes (e.g., acid rain or global warming).
By identifying the system hierarchy, externalities between levels and tradeoffs among components can be traced and explicitly taken into consideration. For example, in an agro-ecological system analyzed at the farm level, the effects of national policies are externalities as long as they are outside the decision context of the farmer (Olembo 1994). Typical tradeoff among components within a farming system includes unproductive fallow lands in a rotation system for the sake of soil recovery for future use. In resource economics the aspect of externalities has gained great importance in that methodologies are being developed to convert such externalities into accountable quantities (Steger 1995), as well as the assignment of “opportunity costs” to tradeoff effects.
Similarly, the “tragedy of the commons” i.e., individual use of common resources can be analyzed adequately only by considering the higher system level to find proper policies for sustainable use e.g., the case of overgrazing in pastoral societies. Such conflicting interests among different groups – or hierarchical levels of the system – is a typical problem in sustainability strategies. Problem analysis is greatly facilitated by system theory to derive alternative scenarios of future development, depending on the policy chosen (Becker 1997).
Thus, agricultural sustainability not only is a difficult concept to define but also is difficult to implement and monitor/measure. This complexity is demonstrated in Table 3 which shows the expected interactions among the three components of sustainability and the five levels of influence. Although sustainability tends to be 80 D. Hayati et al.
expressed, and the ‘secondary’ cells represent other factors that can influence sustainability (Norman et al. 1997) locational or site specific (at the field, farm, and community levels), as Norman
et al. (1997) noted, it is very much influenced by:
1. What happens at the higher levels? National policies have a great influence on ecological and economic sustainability at the field/farm levels. Other policies at that level related to social/institutional issues also can have major effects on the viability/ welfare of communities and, hence, on quality of life. International markets and influences (particularly in smaller countries) are increasingly affecting what happens at the lower levels. Such influences tend to be relatively greater in countries that are poor (low income) and/or where agricultural production is influenced heavily by the export market. Thus, it is necessary to understand the interaction between these levels, because “each level finds its explanations of mechanism in the levels below, and its significance in the levels above” (Bartholomew 1964; Hall and Day 1977).
2. Interactions among the sustainability components. In the focus group discussions with Kansas farmers, some of them indicated that those who were in conventional agriculture were often on an economic treadmill e.g., having to raise enough money to service debts and hence had little time to consider ecological sustainability issues. They also had to make compromises concerning quality of life because of having to work very long hours. In fact, the prevailing attitude among the farmers was that all three components of sustainability (environmental, economic, and social) had to be pursued at the same time, if progress was to be achieved (Norman et al. 1997). A more extreme example of the potentially negative interactions among the components of sustainability occurs in many low income countries, where a close link has been established between poverty and ecological degradation. In parts of West Africa, for example, population pressures and low incomes are forcing farmers to cultivate land that is not suitable for agriculture. They are aware of the problems of doing this, but the short-run economic needs of survival are forcing them to sacrifice long-run ecological sustainability (Ibid). In such a situation, ensuring ecological sustainability without solving the problems of poverty and population pressure on the land is impossible (World Bank 1992).
According to three components of sustainability, Zhen and Routray (2003), proposed operational indicators for measuring agricultural sustainability. These indicators are
summarized in Fig. 1:
Measuring Agricultural Sustainability 81
Fig. 1 Proposed agricultural indicators for measuring sustainability (Zhen and Routray 2003) 5 Criteria for Indicators Selection Considering sustainable agriculture in the global context, preliminary indicators were developed for assessing agricultural sustainability. The preliminary indicators
meet the following suitability criteria (Nambiar et al. 2001):
1. Social and policy relevance (economic viability, social structure, etc.)
2. Analytical soundness and measurability
3. Suitable for different scales (e.g. farm, district, country, etc.)
4. Encompass ecosystem processes and relate to process oriented modeling
5. Sensitive to variations in management and climate
6. Accessible to many users (e.g. acceptability) Table 4, developed by Becker (1997), presents criteria for the selection and evaluation of sustainability indicators. The first demand on sustainability indicators is their scientific validity (BML 1995). Bernstein (1992) demanded that “the ideal trend indicator should be both ecologically realistic and meaningful and managerially useful.” These two key properties should be complemented by the requirement that appropriate indicators be based on the sustainability paradigm (cf. RSU 1994).
This last property explicitly introduces the normative element, guiding selection of the indicator according to the value system of the respective author, institution, or society (Becker 1997).
82 D. Hayati et al.
Fig. 2 Steps in a sustainability assessment procedure (Nijkamp and Vreeker 2000) In the regional sustainability assessment Nijkamp and Vreeker (2000) presented the following steps (Fig. 2). Clearly, various feedback mechanisms and/or iterative steps may also be envisaged and included in this stepwise approach. It goes without saying that the above simplified and schematic general framework for a regional Measuring Agricultural Sustainability 83 sustainability assessment study is fraught with various difficulties of both a theoretical/methodological and empirical/policy nature (Bithas et al. 1997).
6 Indicators of Agricultural Sustainability Two basic approaches to sustainability assessment have been developed: First, the exact measurement of single factors and their combination into meaningful parameters. Second, indicators as an expression of complex situations, where an indicator is “a variable that compresses information concerning a relatively complex process, trend or state into a more readily understandable form” (Harrington et al. 1993).
The term sustainability indicator will be used here as a generic expression for quantitative or qualitative sustainability variables. According to WCED (1987) and Conway’s (1983) definitions, which focuses on productivity trends, both quantitative and qualitative variables concentrate on the dynamic aspect of sustainability over time. Indicators to capture this aspect belong to the group of trend indicators, while state indicators reflect the condition of the respective ecosystem (Bernstein 1992).
In developing environmental indicators for national and international policies it has become common practice to distinguish pressure, state, and response indicators (OECD 1991; Adriaanse 1993; Hammond et al. 1995; Pieri et al. 1995; Winograd 1995). An overview on current sustainability indicators is presented in Table 5.
Extensive set of indicators including biophysical, chemical, economic and social can be used to determine sustainability in a broader sense (Nambiar et al. 2001).
These indicators are:
6.1 Crop Yield Long-term crop yield trends to provide information on the biological productive capacity of agricultural land and the ability of agriculture to sustain resource production capacity and manage production risks.
6.2 Agricultural Nutrient Balance Excessive fertilizer use can contribute to problems of eutrophication, acidification, climate change and the toxic contamination of soil, water and air. Lack of fertilizer application may cause the degradation of soil fertility. The parameters of agriculture nutrient balance are gross nutrient balance (B) and input: output ratio (I/O).
Gross nutrient balances of the total quantity of N, P and K, respectively, applied to agricultural land through chemical fertilizers and livestock manure, input in irrigation, rain and biological fixation minus the amount of N, P and K absorbed by agricultural plants, run-off, leaching and volatilization.
6.3 Soil Quality
Soil quality indicators include physical properties, e.g. soil texture, soil depth, bulk density, water holding capacity, water retention characteristics, water content, etc., chemical properties, e.g. total organic C and N, organic matter, pH, electrical conductivity, mineral N, extracted P, available K, etc., and biological properties, e.g.
microbial biomass C and N, potentially mineralisable N, soil respiration, biomass C/total organic C ratio, respiration: biomass ratio, etc.
6.4 Agricultural Management Practices Management and the type of fertilizers and irrigation systems will affect the efficiency of fertilizer, pesticide and water use. Agricultural management indicators here include efficiencies of fertilizer, pesticide, and irrigated water uses.
6.5 Agri-Environmental Quality These agri-environmental indicators provide information on environmental impacts from the production process. Degrees of soil degradation and water Measuring Agricultural Sustainability 85 pollution are included. The degree of soil degradation is measured by the effects of water and wind erosion, Stalinization, acidification, toxic contaminants, compaction, water logging and declining levels of soil organic matter. The quality of surface, ground and marine water is measured by concentrations in weight per liter of water of nitrogen, phosphorus, dissolved oxygen, toxic pesticide residues, ammonium and soil sediment.
6.6 Agricultural Biodiversity
Biodiversity of plants and livestock used for agricultural production is important to conserve the agro-ecosystem balance. However, the dependence on a limited number of varieties and breeds for agricultural production may increase their susceptibility to pests and diseases. Biodiversity measurement is reflected by the total number of varieties/breeds used for the production of major crops/livestock, and the number of animals and microorganisms in the production.
6.7 Economic and Social
Aspects and sustainable agriculture sustainability of agroecosystems is reflected not only in environmental factors but also in economic soundness and social considerations. These aspects are included as real net output (real value of agricultural production minus the real cost), and the change in the level of managerial skills of farmers and land managers in income and farming practice.
6.8 Agricultural Net Energy Balance
Agriculture not only uses energy such as sunlight and fossil fuels, but also is a source of energy supply through biomass production.