Land resource issues are problems in land use planning and resource management, arising from the interactions between human society and the natural environment. This chapter identifies the key land resource issues for the ‘three worlds of the tropics’, the major agro-ecological zones: the humid tropics or rain forest zone, the subhumid tropics or savannas, and the dry lands, semi-arid and desert. Cutting across these climatic regions are two distinctive environments: steeplands and alluvial lowlands. Land resource issues are related to the essential nature of sustainable land use: combining the efficient use of resources to meet present needs with their conservation for the future. Many issues are concerned with the avoidance of land degradation.

The present rate of world population increase, 240 000 people a day, poses immense problems, not least for land resource management. Future growth will nearly all take place in the developing world. Some countries, such as Bangladesh, Ethiopia, Malawi, Pakistan, and much of the African Sahelian zone, are already close to their limit for sustainable support to their people. Population increase will augment problems of landlessness, land degradation, and food security. Poverty and undernutrition add to these problems. There are also major consequences for human welfare or its opposite, suffering: direct links between population pressure and famine, and indirect but strong connections with civil conflict and war.

Scientists and governments have each made major international policy statements on population. Both accept the integral nature of population, economic growth, and environment, but there is one critical difference. The scientists state clearly that global social, economic, and environmental problems cannot be solved without an early approach to zero population growth, if possible within the lifetime of today's children. The governments could not commit themselves to such a statement. All are agreed on a set of ethically acceptable measures for reducing population growth, based on provision of family planning and reproductive health services, and measures to improve the welfare, education, and status of women. An immediate and major effort to apply such measures would contribute more than any other form of development to human welfare. Policy, planning, and action to check population growth is not merely an associated factor, but in the wider perspective is an integral part of land resource policy and management.

The older approach to land management, based on the transfer of Western technologies, has been replaced by a new set of ideas. For management of the croplands, new approaches include the land husbandry basis for soil conservation, low-input sustainable agriculture, and small-scale irrigation. On open rangelands, reconciling the extreme complexity of land management needs with communal tenure raises problems which are almost insuperable. Multiple-purpose forest management has replaced the earlier focus on wood production. Agroforestry has helped to diversify farm production, and offered new means of soil management.

These new approaches have a number of ideas in common: understanding the processes in the soil, water, and plant ecosystem, as a basis for their modification; adapting management methods to the infinite variety of local conditions; and increasing production not by taking in more land nor with higher inputs, but by using soils, water, fertilizers, and plant resources with greater efficiency. Finally, it has invariably been found that best results come from a participatory approach, implementing changes through the joint efforts of resource scientists and the knowledge and skills of the local people.

Only recently has a fundamental fact been realized in development planning: that whatever may be achieved by development projects, ultimately it is people who manage land resources: farmers, other land users, and local communities. Farm systems research was only a stage along the route to this realization. A true participatory approach is based on the sharing of knowledge and views between advisers and farmers, linking scientific advances with the store of local knowledge. Participatory projects by non-governmental organizations have achieved striking local successes, particularly in the area of soil conservation. But this approach can never be scaled up to reach the rural community at large until it is implemented by countries themselves, either through national advisory services or, if these fail, through self-help by farming communities.

Improvements in land resource management can only come about if they are preceded by awareness of the problems, and recognition of the need for action. At international level, there is a strong measure of agreement on priorities, including poverty reduction, avoidance of land degradation, research, and people's participation in decision-making. At national level, land resource policies cannot be applied in isolation. There first needs to be avoidance of civil conflict, good government, and attention to development of the rural sector, leading to a recognition of the role of land resources. This provides a framework for a set of national land resource policies, including improved survey and evaluation, efforts to combat land degradation, the effective linking of research with extension, a national land use plan, and monitoring of the national heritage of land resources. This will require a strengthening of institutions, with improvements in education and training. None of these measures will be fully effective unless accompanied by greater efforts to reduce rates of population growth; demographic policy is an integral part of rural land development.

Land resources play a critical role in human welfare. Land is no longer abundant, and its productive potential is being reduced by degradation. Sustainability, the combination of production with conservation of resources to meet the needs of future generations, is the key to land management. Whilst a valuable contribution can come from international co-operation, the ultimate responsibility lies with the people and governments of developing countries. Awareness, and with it the will to bring about change, can only come from within.

Despite growing recognition of the importance of environmental criteria, many investment decisions by development agencies are taken primarily on grounds of economics, and, specifically, on returns to investment. If natural resource considerations are to be allotted their rightful importance, there is no avoiding their conversion into money terms. Economic values are needed for analysis of soil and other land conservation projects, for estimating the loss to society caused by land degradation, and for national environmental accounting. Conventional economic methods undervalue natural resources; they may appear to come free, or to be priced at either their marginal or average values, ignoring the far higher price that would be paid if they became scarce. Above all, the practice of discounting, as employed in cost–benefit analysis, grossly underestimates future option values, the value of resources for use in the future. A consequence is that the economic losses caused by erosion, salinization, and other kinds of degradation are greatly undervalued. Economic methods as currently applied give equal weight to the needs of today's poor, but they steal resources, and thus welfare, from future generations. Assigning a value to land resources equal to their productive potential for at least 500 years, which virtually amounts to a sustainability constraint, would help to remedy this iniquitous situation.

Resource surveys and land evaluation studies are only a means to an end. It is at the further stage of land use planning, and projects in the area of natural resource management, that action gets taken. Land use planning does not only mean making plans; it covers their implementation and management, monitoring of progress, and revision. The most important scales are national level, for policy guidance and priorities, and district or project level, where developments are put into practice. Planning must be focused on the problems of land users, but these must be reconciled with other interests. The wide range of objectives, covering production, conservation, and the different sectors of land use, means that no standardized method is possible. The best that can be done is to provide a set of guidelines giving basic steps, with checklists of activities, together with decision support systems. Past experience and informed judgement will always be needed. Natural resource aspects should play a continuing role during the later stages of project planning, including during implementation and monitoring of progress.

The view that further research into land resource management is unnecessary, that all that is needed is more widespread application of existing knowledge, rests on a misunderstanding of the nature of science, in its pure and applied aspects. A spectrum of research is needed: fundamental, basic, applied and adaptive. Universities and international centres are best fitted to carry out fundamental and basic research, national institutions the applied and adaptive. The final stage of research is carried out by farmers, critically trying out new methods. The achievements of the ‘green revolution’ phase of research, based on improved crop varieties, led to threefold to fivefold increases in crop yields. Further advances will be achieved, but more slowly and with greater effort. The problems encountered with high-technology, highinput land use systems have led to a new approach to research, which stresses maintenance of soil biological activity and improved nutrient cycling, leading to more efficient use of limited inputs.

Whether assessed in economic terms or in its wider contribution to human welfare, research produces extremely high ratios between benefits and costs. There is a serious shortfall in funding. At the international level, donors should at least double the proportion of aid directed towards research; by doing so, they will bring longer-lasting benefits to farmers. Still more important is that governments of developing countries should recognize the need to strengthen their presently inadequate national research services. Farmers will not adopt improved methods without a basis of applied and adaptive research to ensure that these are convincingly effective.