As noted earlier in the course, agriculture employs a high proportion of people in the Third World. In this section, we will look at population growth and agricultural development, with a particular emphasis on how population growth results in changes in land use and in utilization of the natural resource base.
The discussion begins with a brief look at the arguments of Boserup concerning induced technological change in agriculture, and then focuses on Rosenzweig and Binswanger's broader analysis of the effects of population growth on production relations in agriculture. We'll conclude with an examination of two case studies: one from Zaire and the other from Rwanda.
Population growth and production relations in agriculture: Boserup and beyond
In considering how population growth influences agricultural development, we begin by noting two points. First, adding more workers to a fixed amount of agricultural land will, other things being equal, result in a diminishing marginal product of labor (law of diminishing marginal returns). Second, it is unlikely that other things will remain equal (i.e., unchanged).
More specifically, in our review of the National Research Council's 1986 report on population growth and economic development in the Third World, we noted that counter to the various arguments that have been made suggesting that there will be adverse effects of population growth, Ester Boserup has stressed the notion that there will be positive effects as well. Most notable in this regard is her view that population pressure on the land will stimulate the search for and adoption of new technologies of production. In essence, then, population growth induces technological change, resulting in higher productivity of agricultural workers.
Boserup's Table 3.2 (overhead presented in class) shows various food supply systems, arrayed in order of the frequency of cropping (i.e., the intensity of land use). The shift from long-fallow to short-fallow systems and then to annual cropping and multicropping is typically associated not only with more intensive land use, but also with increasing population density and technological sophistication in agricultural production.
Rosenzweig et al., in the context of a broad-ranging assessment of production relations in agriculture, provide a concise summary of Boserup's arguments regarding the effects of population growth on agriculture, identifying eight principal consequences:
1. reduced fallow periods;
2. increased investment in land;
3. shift from hand-hoe cultivation to animal traction;
4. adoption of soil fertility maintenance via manuring;
5. reduced average cost of infrastructure;
6. encourages more specialization in production activities;
7. induces a change from general to specific land rights; and
8. reduced per capita availability of common property resources such as forest, bush, and/or grass fallows and communal pastures.
The first four of these effects represent efforts to increase land productivity and to offset the increased labor requirements stemming from more intensive cultivation. The fifth and sixth effects are due to economies of scale resulting from increased population density. The seventh effect generates incentives to undertake investments in specific plots of land in order to intensify production and preserve soil fertility. The eighth effect raises the possibility of overutilization of common property resources (the "tragedy of the commons").
Not only the intensity of agricultural production, but numerous other aspects of production relations in agriculture are affected by population growth and increased population density. This is best illustrated by Rosenzweig et al.'s Table 4.1 (overhead presented in class), which shows how markets for land and labor, credit markets, and various other aspects of production relations in agriculture are likely to vary between land-abundant settings and land-scarce economies.
Boserup and Bandundu: Case study #1
The Boserup induced-technological-change hypothesis, in which there is a positive feedback from population growth and increased population density to agricultural development, provides a basis for some optimism. My paper on "Population Growth, Changing Agricultural Practices, and Environmental Degradation in Zaire" presents a distinctly more pessimistic view.
The paper focuses on the province of Bandundu, immediately to the east of Kinshasa. The population density in this predominantly rural province is rather low (about 19 per square kilometer), and historically food production has been via a long-fallow system of slash-and-burn agriculture.
Although there has been outmigration from Bandundu to Kinshasa, and migration of rural residents to the province's urban areas, the rural population has continued to grow. As the population has increased, more and more land has come under cultivation. Often this has been more marginal land, in terms of its capacity to produce food. This process, called land extensification, in conjunction with growth in the demand for wood as fuel, has contributed to deforestation.
Agricultural intensification, in the form of shortening of fallow periods, has also been evident in Bandundu during the past 15-20 years. This intensification was encouraged not only by population growth within the province, but also by improved access to the Kinshasa market dating back to the late 1970s when a major paved road linking the province to the capital was completed.
Thus, while some elements of the Boserup scenario are present in Bandundu, a number of others are not. Indeed, work by Louise Fresco documents that there have been additional changes in agricultural practices designed to economize on labor (e.g., less care in field preparation) that have had the impact of hastening soil erosion and loss of soil fertility.
There is potential for serious environmental degradation. The gradual destruction of forest and its replacement by open savanna reduces soil fertility. Present practices entail what Dasgupta referred to as "mining" of the soil (cf., his suggestion to use NNP, or Net National Product, which would differ from GNP by taking into account the effects of changes in the natural resource base on future consumption possibilities).
Overall, then, the situation in Bandundu appears to correspond to that described by Lele and Stone in their examination of evidence from six countries in sub-Saharan Africa: "the environmental damage from the reduction of bush fallow, the more intensive use of land without supplementary biological and chemical inputs, and the depletion of forestry resources complicates the transition from low to more densely populated areas as originally envisaged in the Boserup hypothesis."
The concern for the longer run, then, is that the increases in food production that have been realized via intensification will not be sustainable over the long haul. That is, it may not be possible to maintain agricultural yields.
Technology, in the form of improved inputs (high-yielding seeds, fertilizers, pesticides) does exist that would allow maintenance of yields and even further increases in food production. However, the debilitated state of Zaire's economy and transportation infrastructure means that use of improved inputs is not economically feasible. The long-term prospects, then, are not at all appealing.
Demographic pressure in Rwanda: Case study #2
John May's short paper on "Demographic Pressure and Population Policies in Rwanda, 1962-1994" highlights the fact that Rwanda's economic problems are like those faced by other countries in sub-Saharan Africa, yet at the same time more extreme. In large part this is a consequence of the fact that the population density of 292 inhabitants per square kilometer means that Rwanda's density is more than 12 times as high as that for all of sub-Saharan Africa.
Fertility has been very high in Rwanda, reaching a total fertility rate of 8.5 and higher in the late 1970s and early 1980s (see May's Table 2). There is some evidence of a decline during the 1990s, but fertility was still above 6 as of 1992. This high fertility, in conjunction with declining mortality, has resulted in substantial population growth (see his Figure 1).
As shown by May's Table 3, this rapid population growth has been accompanied by distinct changes in land use. More land is being devoted to crop production, while less has been available for pastures and fallow. As with the Bandundu case study, these changes in land use raise serious questions about environmental degradation and sustainability of food crop production (cf., impact on mountain gorillas).
May reviews the various population policies that have been attempted over the past 40 years, beginning with efforts by Belgium during the colonial period to encourage emigration to neighboring countries such as Zaire. The closing of borders after independence in the early 1960s ended this policy.
A second resettlement policy, "paysannats," was attempted in 1963, and entailed resettling people to areas with land available for cultivation. This was discontinued after only a short period because demand for participation exceeded the available land.
Policy aimed directly at slowing demographic growth was initiated only in 1981, when the government launched a national family planning program. Although slow in getting started, this program appears to have contributed (along with delays in marriages due to lack of land) to the modest declines in fertility observed by the early 1990s. However, as mentioned earlier, population growth remained high.
As May notes, population policies were slow to be developed and slow to be implemented, in part because they often were adopted at the insistence of foreign donors rather than reflecting priorities of national leaders.
Attention in Rwanda in the past few years has been focused on the political problems associated with ethnic group rivalries. However, as May argues, once those problems are in the past, "the country will still be confronted with the same problems as before: cramped surface area, lack of natural resources, very high population density, and rapid population growth... [A] reduction in fertility will be necessary to significantly reduce growth rates and restore the promise of a better tomorrow."
Whether or not public policy will be up to this challenge and if individual citizens will respond remains to be seen.