Population and Infrastructure
Soil is a very adaptable substance which can be used for many functions. In most cases soil can be used for decade after decade and, provided it is looked, after can continue to perform a range of roles. There is one major exception to this - that is building on land, sometimes known as soil sealing. Soil sealing represents a loss of soil resources as a result of the land being covered for housing, roads and other construction. In the majority of cases once the soil has been built upon it is unlikely ever to be available for any of the other soil functions such as agriculture, forestry, and varied plant life again. Building on land also completely alters the soils capability to absorb and regulate the flow of water. The limitations created by building on land should cause planners and developers to think carefully about all aspects of how land should be used - but this has often not been the case.
Of course, people need houses in which to live and urban areas, in particular, need supporting 'infrastructure' (roads, railways etc.). With rapid increases in population underway in many countries of the world, more and more land is required for dwellings and infrastructure. Already some countries, such as the Netherlands and Germany, are highly urbanised. The European Commission has reported that in Germany approximately 120 hectares per day have been used for building and infrastructure in recent years alone. Most cities expand in the direction of the most fertile soils and onto soils that are least likely to cause problems to buildings and other infrastructure. In the more developed parts of the world, after decades of more and more people wanting to live in the cities there is now a move by people to live in the suburbs which is taking up new land for building and infrastructure; land that was formerly in agriculture. In the less developed countries, rural poverty combined with serious land degradation has driven many people to migrate to the cities, often accompanied by sprawling suburbs on land which at one time was producing food for the population. In the last 50 years urban areas have expanded by almost 50 percent, taking in more and more land to accommodate the people.
The balance between building on land against using land for food production is a very difficult one to solve, and many similar land-related challenges exist. The population of the world is increasing now at an unprecedented rate and this population will need to be fed. On the other hand the increasing population will need to be housed and have an accompanying infrastructure. But the one use rests very uncomfortably beside the other. For every new house that is built on land that is suitable for agriculture there is less land for future agriculture. All this is at a time when we need to see an increase in crop production worldwide to feed the rapidly growing population.