Much of the literature that assumes that poverty leads to degradation cannot explain instances of (materially) poor communities living sustainably with their environment for centuries. Induced innovation theory suggests that degradation at least in the long run may be self-correcting as resource scarcity and rising private and/or social costs from degradation induce the development and use of new agricultural and resource management practices65 [Hayami and Ruttan (1985) and Boserup (1965)].
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"Farmer-based innovation" describing the evolutionary process of adapting production technology to changes in factor scarcity is reported in a number of studies [for example, see Binswanger and Ruttan (1978), Hayami and Ruttan (1985)]. These explanations draw their inspiration from the experience of the land scarce agricultural economy of Japan, where by the late 1800s biological innovations had begun to increase yields per unit of land while the United States which had many times more land per head of agricultural labor, had adopted a mechanized form of agricultural technology. It was, in response to rising land values in the 1940s, that biological innovations were adopted widely in the United States.
The evidence presented in Farming Systems in the Tropics documents a large literature showing that agricultural innovations are historically associated with increasing population density or increasing market integration in different agroecological zones [Rutenberg (1980)]. This study strongly suggests that most innovation in the tropics was either endogenous or resulted from transfer/adaptation between trading partners. Similarly much of the technical change in crop management and landscape management was a consequence of the crises in soil management. Pingali, Bigot and Binswanger (1987) document a similar of farm management in the area of mechanization.
Other examples of largely endogenous transformation to local land- use innovations and local institutional development include the widely cited experience of the Machakos district in Kenya [Tiffen and Mortimore (1994)]. This heavily degraded area with its very low agricultural productivity and income had a population density beyond its "carrying capacity" in the 1930s. Yet over a 60-year period, although the population increased five-fold and the resource base has not been rehabilitated, the estimated value of agricultural production at constant prices has increased threefold. Despite considerable movement into more marginal agricultural zones, there is widespread tree-growing, most agricultural land has been terraced; and many new agricultural technologies are in use. The availability of good roads, opportunities to grow high value-added products for the Nairobi market and access to capital for land-related investments (terracing, tree growing, live fencing, water harvesting) enabled this change. The opportunities to generate off farm incomes aided in the process.
Several other examples available in literature deserve to be mentioned. A study by Scherr (1993) documents the case of two districts in the mid- altitude region of Kenya near Lake Victoria where degradation of land and reduced crop yields and subsistence scarcities led to agroforestry strategies oriented towards intensification. The studies by Migot-Adholla et al. (1991) and Place and Hazell (1993) document endogenous change in property rights in Africa. Place and Hazell (1993) found that the binding constraints to agricultural productivity were in fact lack of improved technology and inadequate access to credit.
The Induced Innovation Model in Natural Resource Management assumes that, with increasing population density or market demand, four distinct phases/time periods of management response can be identified. In the model the total supply of services and products from a given resource are a function of its quantity, quality and productivity of use. The first phase is characterized by dependence on naturally occurring resources. The second stage marks the period of resource degradation. The third phase marking the onset of resource rehabilitation occurs with transition to intensive management because the benefits from the investment in resource rehabilitation outweigh the costs. The fourth phase is characterized by dependence on human managed resources (for example agro-forestry, forest plantations and managed reserves). Most of the observed degradation can be explained by assuming that the innovative responses of phases three or four have not occurred. In many cases it can be shown that these have been delayed due to a number of conditions.
However, there is considerable controversy over the adoption of conservation strategies. One school of thought maintains strongly that adoption of land conservation technologies is low across all agricultural environments despite major support and investment in research and development on the problem. Instances where land degradation management have been successful are known66 but analysis of these instances have not yet provided clear guidance to policy makers, researchers or developers to enable more general adoption of these technologies [World Bank (1991a)]. The other school maintains that the lack of adoption of conservation technologies results from a lack of incentives.67 "The success of conservation measures is highly dependent on farmers receiving crop yield and economic benefits in the first or second season after implementation" [FAO (1989)]. This debate highlights the need to understand more fully why resource users do what they do, and how they reach decisions on resource use and environmental management [Biot et al. (1995)]. This debate does not differentiate between the behavior of poor versus non poor.
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Several successful farmer controlled soil conservation methods have been developed and implemented at reasonable cost: A century's old practice in India is being rediscovered, adapted and promoted. Deeply rooted, hedge forming vetiver grass, planted in contour strips across hill slopes, slows water run off dramatically, reduces erosion, and increases the moisture available for crop growth. A quiet revolution has taken place and today 90 percent of soil conservation efforts in India are based on such biological systems. In the Sahel simple technologies involving construction of rock bunds along contour lines for soil and moisture conservation in Burkina Faso have on average increased yields by 10 percent in normal years and in dryer years by almost 50 percent. The Central Visayas Regional Development Project in the Philippines couples the promotion of contour grass strips for erosion control with distribution of young animals. The cost of preventing soil erosion and degradation are comparatively small while the costs of rehabilitating degraded areas can be large [FAO (1992)].
67 Investment in land will depend on the importance of the farm vis. vis. non-farm incomes. There is considerable evidence that non-farm and off-farm incomes are relatively more important to livelihood security in areas with poor land [See Adams (1995) for examples from fragile agricultural areas in Pakistan].
