325 10 Multi-Scale Integrated Analysis of Agroecosystems: Technological Changes and Ecological Compatibility According to the analysis presented in the previous chapter, a general increase of both the demographic and bioeconomic pressure on our planet is the main driver of intensification of agricultural production at the farming system level. In turn, a dramatic intensification of agricultural production can be associated with a stronger interference on the natural mechanisms of regulation of terrestrial ecosystems—that is, to a reduced ecological compatibility of the relative techniques of agricultural production. To deal with this problem, it is important to first understand the mechanisms through which changes in the socioeconomic structure are translated into a larger interference on terrestrial ecosystems. This is the topic of this chapter. Section 10.1 studies the interface socioeconomic context- farming system. At the farm level, in fact, the selection of production techniques is affected by the typology of boundary conditions faced by the farm. In particular, this section focuses on the different mix of technical inputs adopted when operating in different typologies of socioeconomic context. Section 10.2 deals with the nature of the interference on terrestrial ecosystems associated with agricultural production. A few concepts introduced in Part 2 are used to discuss the possible development of indicators. The interference generated by agriculture can be studied by looking at the intensity of the throughput of appropriated biomass per unit of land area. Changing the metabolic rate of a holarchic system (such as a terrestrial ecosystem) requires (1) a readjustment of the relative size of its interacting parts, (2) a redefinition of the relation among interacting parts and (3) changing the degree of internal congruence between produced and consumed flows associated with its metabolism. When the external interference is too large, we can expect a total collapse of the original system of controls used to guarantee the original identity of the ecosystem. Finally, Section 10.3 looks at the big picture presenting an analysis, at the world level, of food production. This analysis explicitly addresses the effect of the double conversion associated with animal products (plants produced to feed animals). After examining technical coefficients and the use of technical inputs related to existing patterns of consumption in developed and developing countries, the analysis discusses the implications for the future in terms of expected requirement of land and labor for agricultural production. 10.1 Studying the Interface Socioeconomic Systems-Farming Systems: The Relation between Throughput Intensities 10.1.1 Introduction After agreeing that technological choices in agriculture are affected by (1) characteristics of the socioeconomic system to which the farming system belongs, (2) characteristics of the ecosystem managed for agricultural production and (3) farmers’ feelings and aspirations, it is important to develop models of integrated analysis that can be used to establish bridges among these three different perspectives. This requires defining in nonequivalent ways the performance of an agroecosystem in relation to (1) socioeconomic processes, (2) ecological processes and (3) livelihood of households making up a given farming system. © 2004 by CRC Press LLC Multi-Scale Integrated Analysis of Agroecosystems326 The link between economic growth and the increases in the intensity of the throughput per hour of labor and per hectare at the societal level (due to increasing bioeconomic and demographic pressure) has been explored in Chapter 9. That is, that chapter addresses the link related to the first point of the previous list. This chapter explores the implications of the trend of intensification of agricultural production in relation to ecological compatibility—it addresses the link implied by the second point of the list. An integrated analysis reflecting the perspective of farmers seen as agents in relation to the handling of these contrasting pressures at the farming system level—the link implied by the third point of the list—is proposed in Chapter 11. The need to preserve the integrity of ecological systems—the ecological dimension of sustainability— in effect can be seen as an alternative pressure coming from the outside of human systems, which is contrasting the joint effect of demographic and bioeconomic pressure, a pressure for growth coming from the inside. That is, whereas human aspirations for a better quality of life and freedom of reproduction push for increasing the intensity of the throughputs within the agricultural sector, a more holistic view of the process of co-evolution of humans with their natural context provides an opposite view, pushing for keeping as low as possible the intensity of throughput of flows controlled by humans within agroecosystems. As noted in Part 1, the sustainability predicament is generated by the fact that these two contrasting pressures are operating at different hierarchical levels, on different scales, and this makes it difficult to interlock the relative mechanisms of control. At the level of individual farms, at the level of villages, at the level of rural areas, at the level of whole countries and at the supranational level, different rules, habits, allocating processes, laws and cultural values are operating for enforcing the two views. However, an overall tuning of this complex system of contrasting goals is anything but easy—especially when considering that humankind is living in a fast period of transition, which implies the existence of huge gradients among socioeconomic systems (very rich and very poor) operating on different points of the evolutionary trajectory. This implies that human agents at different levels, at the moment of technological choices, must decide the acceptability of compromises (at the local, medium or large scale) in relation to the contrasting implications of these two pressures. This chapter obviously does not claim to be able to solve this Yin-Yang predicament. Rather, the goal is to show that it is possible to use the pace of the agricultural throughput to establish a bridge between the perception and representation of benefits and constraints coming from the societal context (when using the throughput per hour of labor) and the perception and representation of benefits and constraints referring to the ecological context (when using the throughput per hectare) of a farm. To make informed choices, it is important to have a good understanding of the mechanisms linking the two types of pressures: (1) the internal asking for a higher level of dissipation and therefore for an expansion into the context and (2) the external reminding that a larger level of dissipations entails higher stress on boundary conditions and therefore a shorter life expectancy for the existing identity of the socioeconomic system generating the ecological stress. The debate over sustainability, in reality, means discussing the implications of human choices when looking for compromise solutions between these two pressures. The analysis described in Section 9.4 (Figure 9.12 through Figure 9.15) indicates the existence of a clear link between the values taken by: 1. Relevant characteristics of the food system defined at the hierarchical level of society (using the two IV3: APDP and AP BEP ), which can be characterized by a set of variables such as gross national product (GNP) and density of produced flow, which can be related to other relevant system qualities such as age structure, life span of citizens, profile of labor distribution over economic sectors, and workload (as discussed in Chapter 9). These variables refer to the societal system seen as a whole, without any reference to the farming system level. 2. Relevant characteristics of the food system defined at the hierarchical level of the farming system (using the two IV3: AP ha and AP hour ), which are determined by a set of biophysical constraints such as technical coefficients, technical inputs and climatic conditions, and location-specific socioeconomic constraints such as local prices and costs and local laws. These characteristics, for example, refer to the horizon seen by farmers when making their living. The variables used to represent these system qualities are well known to the agronomist, agricultural economists and © 2004 by CRC Press LLC Multi-Scale Integrated Analysis of Agroecosystems 327 agroecologists (technical coefficients, economic parameters characterizing the economic performance of the farm, local indicators of environmental stress). This link among two different hierarchical levels—society as a whole (level n) and individual farming system (level n-1)—can be visualized by using a plane describing the agricultural throughput according to two IV3: (1) agricultural throughput per hectare (when using human activity as EV2) and (2) agricultural throughput per hour (when using land area as EV2). In this way, the technical performance of a farming system can be described in parallel on two levels (Figure 10.1): • On the level n, society as a whole, by considering values of AP DP and AP BEP (which are two types of IV3 n ) assessed by using societal characteristics. These values must be compatible with the constraints coming from the socioeconomic structure associated with the particular typology of societal metabolism. • On the level n-1, individual farming system, by considering values of AP ha and AP hour (which are two types of IV3 n-1). These values must be feasible according to local economic and biophysical constraints and available technology. In this way, the characteristics of an agricultural throughput can be seen as determined by (1) the set of constraints coming from the context (societal level) and (2) the set of constraints operating at the farming system level. On the upper plan of Figure 10.1 (with the axes×and y represented by values of AP DP and AP BEP , respectively) it is possible to define areas of feasibility for agricultural throughputs according to socioeconomic characteristics. As noted earlier, developed countries require agricultural throughputs above 5000 kg of grain per hectare and above 250 kg of grain per hour of labor, when talking of cereal cultivation. On the lower plan (with the axes×and y represented by values of AP ha ? kg ha and AP hour ? kg hour , respectively) it is possible to define areas of feasibility for agricultural throughputs according to farm-level constraints and characteristics of techniques of production. For example, subsistence societies that do not have access to technical inputs cannot achieve land and labor productivity higher than 1000 kg of grain per hectare and 10 kg of grain per hour (clearly, these values are general indications and are not always applicable to special cases—e.g., delta of rivers). As noted earlier, we can expect that farming systems belonging to a particular socioeconomic system tend to adopt techniques of production described FIGURE 10.1 The link between two assessments based on two definitions of IV3. AP hour and AP ha at level n—1 and AP BEP - AP DP at level n. (Giampietro, M, (1997a), Socioeconomic pressure, demographic pressure, environmental loading and technological changes in agriculture, Agric. Ecosyst. Environ., 65, 219–229.) © 2004 by CRC Press LLC Multi-Scale Integrated Analysis of Agroecosystems328 by a combination of values of AP ha and AP hour that keep them as much as possible close to the area determined by socioeconomic constraints. In conclusion, when describing technological development in agriculture on a plane AP DP —APBEP we can expect that: • Farming systems operating within different socioeconomic contexts (in societies described by different combinations of AP DP —AP BEP ) tend to operate in range of land and labor productivity (AP ha —AP hour ) close to the values defined by socioeconomic constraints. As noted in Chapter 9, whenever a biophysical constraint on land imposes an APhour AP BEP (in developed countries), imports (market and trade) must be available to cover the difference. Getting into an economic reading, in a situation in which ELP AG << ELP PW , farmers require protection from international competition and direct subsidies, to keep a level of income similar to that achieved by workers making a living in other economic sectors. This requires the availability of financial resources (surplus of added value), at the country level, which can be allocated to subsidize the agricultural sector. • Changes in demographic and socioeconomic pressure (AP DP —AP BEP ) will be reflected, sooner or later, in changes of technical coefficients of farming techniques (AP ha —AP hour ). As soon as economic growth (parallel increase in GNP per capita (p.c.) and population size) translates into a parallel increase of demographic and socioeconomic pressure, technical progress is coupled to changes in socioeconomic characteristics that require techniques of agricultural production characterized by high values of AP hour The same link between economic development and increases in labor productivity in agriculture is found when adopting a more conventional economic reading of technological development of agriculture (Hayami and Ruttan, 1985). According to this integrated analysis, we should be able to represent general trends in the evolution of food production techniques for different types of socioeconomic systems on the two-dimensional plane (made using IV3): productivity of land (kilograms per hectare) and productivity of labor (kilograms per hour), as illustrated in Figure 10.2. For the sake of simplicity, the plane describes productivity of land and labor mapped in terms of kilograms of grain. Four main types of socioeconomic systems, having different combinations of demographic and bioeconomic pressure, are represented there: 1. Socioeconomic systems with low demographic and low bioeconomic pressure. This situation is characterized by more than 0.5 ha of arable land per capita (this value depends on available productive land and population size) and less than $1000 per year of GNP per capita (depending on economic performance). This type of socioeconomic system includes several African countries, such as Burundi. 2. Socioeconomic systems with low demographic and high bioeconomic pressure. This situation is characterized by more than 0.5 ha of productive land per capita and more than $10,000 per year of GNP per capita. This type of socioeconomic system includes countries such as the U.S., Canada, and Australia. 3. Socioeconomic systems with high demographic and low bioeconomic pressure. This situation is characterized by less than 0.2 ha of arable land per capita and less than $1000 per year of GNP per capita. This type of socioeconomic system includes countries such as China and Egypt. 4. Socioeconomic systems with high demographic and high bioeconomic pressure. This situation is characterized by less than 0.2 ha of arable land per capita and more than $10,000 per year of GNP per capita. This type of socioeconomic system includes several countries of the European Union and Japan, among others. According to existing trends in population growth and economic development for these four different types of socioeconomic systems, we can expect the following movements in the plane (see Figure 10.2): © 2004 by CRC Press LLC Multi-Scale Integrated Analysis of Agroecosystems 329 1. Societies with low demographic and bioeconomic pressure (e.g., some African countries): The population is growing faster than the GNP per capita, which means that AP DP will grow faster than AP BEP . Hence, they will move toward a situation typical of China. 2. Societies with low demographic and high bioeconomic pressure (e.g., Canada, U.S.): Economic development is expected to be maintained (GNP per capita will remain high) and population growth will be relatively slow but steady (medium or low internal fertility but high immigration rate). On the plane, this means a slow movement toward higher values of AP DP 3. Societies with high demographic and low bioeconomic pressure (e.g., China): These societies look for a quick economic growth (increasing GNP per capita) and they are expected to maintain if not expand their already huge population size. At a national level, an increasing GNP per capita will result in an accelerated absorption of the labor force currently engaged in agriculture (e.g., 60% in China at present) by other sectors (primary and service sectors) of the economy. This will inevitably require a dramatic increase in agricultural labor productivity (AP hour ) to maintain food security. Hence, a movement toward the West European conditions of agricultural production is to be expected. 4. Societies with high demographic and bioeconomic pressure (e.g., The Netherlands, Japan): These societies have no alternative but to try to maintain a high material standard of living and keep population growth to a minimum. This means a more or less stable and high level of AP BEP and a very slowly increasing value of AP DP (mainly due to the strong pressure of immigrants). For these societies, trying to reduce the environmental impact of their food production becomes a major factor. Note that food imports from the international market, a must for countries where biophysical or economic constraints determine a value of AP DP > AP ha or AP] BEP >AP hour , are based on the existence of surpluses FIGURE 10.2 Trends and changes in production techniques over a plane labor productivity×land productivity. (Giampietro, M, (1997a), Socioeconomic pressure, demographic pressure, environmental loading and technological changes in agriculture, Agric. Ecosyst. Environ., 65, 219–229.) © 2004 by CRC Press LLC Multi-Scale Integrated Analysis of Agroecosystems330 produced by countries where the relation between these parameters is inverse. Countries producing big surpluses in relation to both types of pressures are scarce. In 1992, the U.S., Canada, Australia and Argentina combined produced over 80% of the net export of cereal on the world market (WRI, 1994), but at their present rate of population growth (including immigration) and because of an increasing concern for the environment (policies for setting aside and developing low-input agriculture), this surplus might be eroded in the near future. For instance, the U.S. is expected to double its population in 60 years (USBC, 1994). However, the situation is aggravated when including in this analysis the legitimate criteria of respect of ecological integrity. This criterion is already leading to a push for a less intensive agriculture all over the developed world (slowdown, at the farming level, of the rate of increase in AP ha ). This combined effect could play against the production of food surpluses in those countries that could do so. In conclusion, at the world level, demographic and bioeconomic pressures are certainly expected to increase, forcing the countries most affected by those two pressures to rely on imports for their food security. It is often overlooked that at the world level, there is no option to import food from elsewhere. When increases in demographic and bioeconomic pressure are not matched by an adequate increase in productivity of land and labor in agriculture, food imports of the rich will be based on starvation of the poor. This simple observation points at the unavoidable question of the severity of biophysical constraints affecting the future of food security for humankind. How do these trends fit the sustainability of food production at the global level? The rest of this section focuses on the changes in techniques of production (in particular in the pattern of use of technical inputs) that can be associated with changes in demographic and bioeconomic pressure as perceived and represented from the lower level (changes in techniques of production at the farm level). Section 10.2 deals with the relation between changes in techniques of production associated with changes in demographic and bioeconomic pressure as perceived and represented from the higher level—the aggregate effect that these changes have on the integrity of terrestrial ecosystems. This is where the ecological dimension of sustainability becomes crystal clear. Agricultural production, in fact, depends on the stability of boundary conditions for the productivity of agroecosystems. Finally, Section 10.3 explores the relation between qualitative changes in the diet—the implications of increasing the fraction of animal products and fresh vegetables and fruits (changes in the factor QDM (quality of diet multiplier))—and changes in the profile of use of technical inputs in perspective and at the world level. Increasing the amount of animal products in the diet requires a double conversion of food energy (energy input to crops and crops to animals). In the same way, increasing the amount of fresh vegetables in the diet requires a mix of crop production associated with a much higher investment of human labor per unit of food energy produced and a reduced supply of food energy per hectare. Both changes (typical of the diet of developed countries) represent an additional boost to the problems associated with higher demographic and bioeconomic pressure. 10.1.2 Technical Progress in Agriculture and Changes in the Use of Technical Inputs The classic analysis of Hayami and Ruttan (1985) indicates that two forces are driving technological development of agriculture: 1. The need to continuously increase the productivity of labor of farmers; this is related to the need of: a. Increasing income and standard of living of farmers b. At the societal level, making more labor available for the development of other economic sectors during the process of industrialization. 2. The need to continuously increase the productivity of agricultural land. This is related to the growing of population size, which requires guaranteeing an adequate coverage of internal food supply using a shrinking amount of agricultural land per capita. It is important to understand the mechanism through which bioeconomic and demographic pressure push for a higher use of technical inputs in agriculture. In fact, the effect of these forces is not the same in developed and developing countries. In developed countries, the increasing use of fossil energy had © 2004 by CRC Press LLC Multi-Scale Integrated Analysis of Agroecosystems 331 mainly the goal of boosting labor productivity in agriculture to enable the process of industrialization. This made possible a massive move of the workforce into industrial sectors, increasing at the same time the income of farmers. For example, in West Europe the percentage of the active population employed in agriculture fell from 75% before the industrial revolution (around the year 1750) to less than 5% today. In the U.S., this figure fell from 80% around the year 1800 to only 2% today. As observed in Figure 9.12, none of the countries considered in that study with a GNP per capita higher than $10,000 per year has a percent of workforce in agriculture above the 5% mark. In the same way, none of the countries with more than 65% of the workforce in agriculture has a GNP per capita higher than $1000 per year of GNP. The supply of human activity allocated in work (HA PS ) is barely capable of producing the food consumed by society; there is no room left for the development of other activities of production and consumption of goods and services not related to food security. In developing countries, the growing use of fossil energy has been, up to now, mainly related to the need to prevent starvation (just producing the required food) rather than to increase the standard of living of farmers and others. Concluding his analysis of the link between population growth and the supply of nitrogen fertilizers, Smil (1991, p. 593) beautifully makes this point: The image is counterintuitive but true: survival of peasants in the rice fields of Hunan or Guadong— with their timeless clod-breaking hoes, docile buffaloes, and rice-cutting sickles—is now much more dependent on fossil fuels and modern chemical syntheses than the physical wellbeing of American city dwellers sustained by Iowa and Nebraska farmers cultivating sprawling grain fields with giant tractors. These farmers inject ammonia into soil to maximize operating profits and to grow enough feed for extraordinarily meaty diets; but half of all peasants in Southern China are alive because of the urea cast or ladled onto tiny fields—and very few of their children could be born and survive without spreading more of it in the years and decades ahead. The profile of use of technical inputs can be traced more or less directly to these two different goals. Machinery and fuels are basically used to boost labor productivity, whereas fertilizers and irrigation are more directly related to the need to boost land productivity. The data presented in this section are taken from a study of Giampietro et al. (1999). Twenty countries were included in the sample to represent different combinations of socioeconomic development (as measured by GNP) and availability of arable land (population density). Developed countries with low population density are represented by the U.S., Canada and Australia. Developed countries with high population density include France (net food exporter), the Netherlands, Italy, Germany, the U.K. and Japan (net food importers). Countries with an intermediate GNP include Argentina (with abundant arable land), Mexico and Costa Rica. Countries with a low GNP and little arable land per capita include the People’s Republic of China, Bangladesh, India and Egypt. Other countries with low GNP include Uganda, Zimbabwe (net food exporters), Burundi and Ghana. The data on input use refer to the years 1989 and 1990. Technical details can be found in that paper. The relation between the use of irrigation and the amount of available arable land per capita over this sample of world countries is shown in Figure 10.3. The upper graph clearly indicates that the different intensities in the use of this input reflect differences in demographic pressure (the curve is smooth in the upper graph—Figure 10.3a) more than differences in economic development. If we use the same data of irrigation use vs. an indicator of bioeconomic pressure (e.g., GNP p.c.), we find that crowded countries, either developed or developing, tend to use more irrigation than less crowded countries, with very little relevance of gradients of GNP (Figure 10.3b). It is remarkable that exactly the same pattern is found when considering the use of synthetic fertilization over the same sample of countries (Figure 10.4). The upper and lower graphs of Figure 10.4 are analogous to those presented in Figure 10.3 for irrigation. The only difference is that they are obtained with data referring to nitrogen fertilizer. The similarity between the two sets of figures (Figure 10.4a and Figure 10.3a vs. Figure 10.4b and Figure 10.3b) is self-explanatory. Demographic pressure seems to be the main driver of the use of nitrogen and irrigation. Completely different is the picture for another class of technical inputs: machinery (tractors and harvesters in the Food and Agriculture Organization (FAO) database used in the study of Giampietro et © 2004 by CRC Press LLC Multi-Scale Integrated Analysis of Agroecosystems332 al. (1999)). The two graphs in Figure 10.5 indicate that machinery for the moment is basically an option of developed countries (Figure 10.5b). Within developed countries, huge investments in machinery can be associated with large availability of land in production. This is perfectly consistent with what is discussed in Chapter 9. To reach a huge productivity of labor, at a given level of yields, it is necessary to increase the amount of hectares managed per worker. This requires both plenty of land in production and an adequate amount of exosomatic devices (technical capital) to boost human ability to manage large amounts of cropped land per worker. This rationale is confirmed by the set of data represented in the graph of Figure 10.6a. Over the sample considered in the analysis of Giampietro et al. (1999), the highest levels of labor productivity are found in the agricultures that have available the largest endowment of land in production per worker. Finally, it should be noted that there is a difference between agricultural land per capita (land in production divided by population) and agricultural land per farmer (land in production divided by workers in agriculture). In fact, a reduction of the workforce in agriculture (e.g., by reducing the fraction of the workforce in agriculture from 80 to 2%) can increase the amount of land per farmer at a given level of demographic pressure. However, this reduction of the workforce in agriculture can only have a limited effect in expanding the land in production per farmer. An economically active FIGURE 10.3 (a) Irrigation and demographic pressure. (b) Irrigation and bioeconomic pressure. (Giampietro, M. Bukkens, S., Pimentel, D., (1999), General trends of technological change in agriculture, Crit. Rev. Plant Sci. 18, 261–282.) © 2004 by CRC Press LLC Multi-Scale Integrated Analysis of Agroecosystems 333 population is only half of the total population, and when the accounting is done in hours of human activity, rather than in people, we find that the effect on AP BEP is even more limited, since HA Working is only 10% of total human activity (THA). When looking at the existing levels of demographic pressure and the existing gradients between developed and developing countries (Figure 10.6b), it is easy to guess that such a reduction, associated with the process of industrialization, will not even be able to make up for the increase in the requirement of primary crop production associated with the higher quality of the diet (higher quality of diet mix and postharvest losses), which industrialization tends to carry with it (more on this in Section 10.3). 10.1.2.1 The Biophysical Cost of an Increasing Demographic and Bioeconomic Pressure: The Output/lnput Energy Ratio of Agricultural Production— The output/input energy ratio of agricultural production is an indicator that gained extreme popularity after the oil crisis in the early 1970s to assess the energy efficiency of food production. Assessments of this ratio are obtained by comparing the amount of endosomatic energy contained in the produced agricultural output to the amount of exosomatic energy embodied in agricultural inputs used in the process of production. Being based on accounting of energy flows, such an assessment is generally controversial (see technical section in Chapter 7). The two most famous problems are (1) the truncation problem on the definitions of an energetic equivalent for each one of the inputs (Hall et al., 1986) (as FIGURE 10.4 (a) Nitrogen fertilizer and demographic pressure. (b) Nitrogen fertilizer and bioeconomic pressure. (Gi-ampietro, M., Bukkens, S., Pimentel, D., (1999), General trends of technological change in agriculture, Crit. Rev. Plant Sci., 18, 261–282.) © 2004 by CRC Press LLC Multi-Scale Integrated Analysis of Agroecosystems334 noted in Chapter 7, this has to do with the hierarchical nature of nested dissipative systems) and (2) the summing of apples and oranges—in particular the most controversial assessment of energy input is that related to human labor (especially the summing done by some analysts of endosomatic and exosomatic energy) (Fluck, 1992). As noted in Chapter 7, this has to do with the unavoidable arbitrariness of energy assessments that, rather than linear analysis, would require the adoption of impredicative loop analysis (ILA). Methodological details are, however, not relevant here. This ratio is generally assessed by considering (1) the output in terms of an assessment of an amount of endosomatic energy that is supplied to the society (e.g., the energy content of crop output) and (2) the input in terms of an assessment of an amount of exosomatic energy consumed in production. To obtain this assessment, it is necessary to agree on a standardized procedure (e.g., on how to calculate the amount of fossil energy embodied in the various inputs adopted in production). If the analysis focuses only on the embodied requirement of fossil energy in the assessment of the input, then the resulting ratio (the amount of fossil energy consumed per unit of agricultural output) can be used as an indicator of biophysical cost of food. In fact, it measures the amount of exosomatic energy (one of the possible EV2—fossil energy—that can be used for the analysis of the dynamic budget of societal metabolism) that society has to extract, process, distribute and convert into useful power to produce a unit of food energy. FIGURE 10.5 (a) Machinery and demographic pressure. (b) Machinery and bioeconomic pressure. (Giampietro, M. Bukkens, S., Pimentel, D., (1999), General trends of technological change in agriculture, Crit. Rev. Plant Sci. 18, 261–282.) © 2004 by CRC Press LLC [...]... © 2004 by CRC Press LLC Multi- Scale Integrated Analysis of Agroecosystems TABLE 10. 4B Animal Products, Feed Ingredients and Forage Used in Animal Production (Million MT) Multi- Scale Integrated Analysis of Agroecosystems • • • • • 359 For pulses—8 MJ/kg in developed countries and 4.7 MJ/kg in developing countries (assuming output/input ratios of 1.8/1 and 3/1) A 10% overhead of fossil energy for making... load of pollution of nitrogen from the ponds) (Gomiero et al., 1997) Actually, weeds are often planted by Chinese farmers around © 2004 by CRC Press LLC Multi- Scale Integrated Analysis of Agroecosystems FIGURE 10. 17 Trophic pyramids in natural and human-managed freshwater systems (Modified from Gomiero, T et al., Agric Ecosyst Environ., 62, 16 9-1 85.) 351 © 2004 by CRC Press LLC 352 Multi- Scale Integrated. .. Figure 6 .10) to the analysis of changes in turnover time of biomass over populations (considered as elements of a network) © 2004 by CRC Press LLC Multi- Scale Integrated Analysis of Agroecosystems 343 In his discussion of the mechanism governing population growth, Lotka (1956, p 129, emphasis mine) downplays the importance of fertility and mortality rates in defining the dynamics of growth of a particular... reshuffling of the profile of investment of the resource chemical bonds available to the ecosystem over the lower-level component (either to boost final consumption or to increase the level of capitalization of the system—increasing SB) This, in Figure 10. 15 at the level of angle (3, translates into a major distortion of the natural profile of the Eltonian pyramid of the disturbed ecosystem An analysis of this... example of biomass of different compartments of different ecosystems, 1 kg of ecosystem biomass in the tundra has a very high level of dissipation (the ratio of energy dissipated to maintain a kilogram of organized structure in its expected associative context).This high level of dissipation can be explained by its ability to survive © 2004 by CRC Press LLC Multi- Scale Integrated Analysis of Agroecosystems. .. the possibility of establishing a relation among certain system qualities That is: 1 To have a high level of GPP, an ecosystem must have a large value of SB In the analogy with the economic narrative, this would imply that to generate a lot of added value, an economic system must have a lot of capital © 2004 by CRC Press LLC 346 Multi- Scale Integrated Analysis of Agroecosystems FIGURE 10. 14 GPP, NPP... hectare on marginal lands requires large amounts of fossil energy-based inputs This occurs at the very same time that the economic growth of many developing countries is dramatically increasing the demand of oil for © 2004 by CRC Press LLC Multi- Scale Integrated Analysis of Agroecosystems 337 FIGURE 10. 8 Adding a third axis to the plane shown in Figure 10. 2 (Giampietro, M., (1997a), Socioeconomic pressure,... by CRC Press LLC 348 Multi- Scale Integrated Analysis of Agroecosystems FIGURE 10. 16 Plane to represent the alteration of terrestrial ecosystems (adopting a thermodynamic rationale) according to the natural process of self-organization Human intervention is therefore viewed as an interference preventing the most probable state of a dissipative system from a thermodynamic point of view This makes it... should not be considered a good optimizing parameter Very high values of © 2004 by CRC Press LLC 336 Multi- Scale Integrated Analysis of Agroecosystems FIGURE 10. 7 Combined effect of demographic and socioeconomic pressure on technical performance of agricultural production (Giampietro, M., Bukkens, S., Pimentel, D., (1999), General trends of technological change in agriculture, Crit Rev Plant Sci., 18, 261–282.)... system © 2004 by CRC Press LLC Multi- Scale Integrated Analysis of Agroecosystems 339 FIGURE 10. 9 Combined effect of demographic and socioeconomic pressure on the environmental loading of agriculture (Giampietro, M., (1997a), Socioeconomic pressure, demographic pressure, environmental loading and technological changes in agriculture, Agric Ecosyst Environ., 65, 21 9-2 29.) 10. 2.2 The Food System Cycle: . 325 10 Multi- Scale Integrated Analysis of Agroecosystems: Technological Changes and Ecological Compatibility According to the analysis presented in the previous chapter, a general increase of. LLC Multi- Scale Integrated Analysis of Agroecosystems 339 10. 2.2 The Food System Cycle: Combining the Two Interfaces of Agriculture The overlapping within the agricultural sector of flows of energy. way, humans keep the FIGURE 10. 11 (a) Low-input agriculture. (b) High-input agriculture. © 2004 by CRC Press LLC Multi- Scale Integrated Analysis of Agroecosystems3 42 flow of produced biomass tightly