From the roll call of the ancients: Aztecs of Mexico, the Mayas of Middle America and the Singhalese of Ceylon etc., they all have numerous similarities in that the land that they previously lived on is today often wasteland and unproductive. A great variety of theories have been proposed as to the specific reasons why ancient civilisations have flourished in some regions and failed to develop in others [Cater, Dale, 1974] and some historians [Piggott, 1961, Fagan, 1974] attribute the decline or destruction of individual cities and civilisations to war and conquest [Cox et al. 1984]. However, Carter and Dale note that political corruption, war, conquest etc. may have forced a civilisation into decline, but they were usually re-established if the region had enough natural resources, such as soil, to support the continuation of succeeding civilisations and the re-building of cities.

It is apparent that a change in climate has also been attributed to the decline in civilisations [Cox et al. 1984; Piggott, 1961], but again Carter and Dale [1974] believe that there is not a correlation between changes in rainfall over the centuries and the rise and fall of civilisations. This subject is wide open to debate and conjecture for example, today, Sicily is a well rained on desert and yet it was formally a highly productive land as the Minoan civilisation developed [Carter, Dale, 1974]. In effect there was not a lack of water, but rather a lack of vegetation and the soil that supports it. These factors have greatly contributed to the primary cause of the failure of many ancient civilisations. In a similar fashion the rainfall has declined in some regions and this could have contributed to the loss of vegetation, which has also been greatly influenced by the decline in vegetation, due to poor agricultural practices. The combination of all these factors have in turn contributed to a civilisation's demise. There are, however, no general rules for Fagan [1974] notes that in the Saharan grasslands there have been a succession of Stone Age hunters and gatherers, Nomads and farmers, yet the increasing aridity has turned this area into desert. Was this due to climatic change only or to a man induced change of environment that in turn contributed to the change in climate? Both Mitchell [1946] and Richardson and Stubbs [1978] report that two thousand years ago the Sahara Desert region of Africa was a lush grazing and productive forested area, but is now a wasteland due to deforestation and abusive unsustainable agricultural practices which have changed the landscape and altered rain patterns.

Carter and Dale [1974] make the assumption that there is a direct relationship between the primary decline of most civilisations and the exploitation of resources and in particular top soil. The history of agriculture can be clearly related to the history of accelerated erosion as a soil depletion process. In effect the ancients wore out their land in the process of developing their civilisations. Ancient civilisations blossomed as they had their resources or traded for them. The quality and quantity of agricultural land has been the dominant natural resource determining the rise, duration and fall of urban civilisations [Cox et al. 1984].

There would appear to be an established pattern in the rise and fall of ancient urban civilisations throughout the world with most civilisations being based in or close to land that was productive and capable of feeding a large population [Cox et al. 1984; Carter, Dale, 1974]. Several inter-related patterns that have emerged with the average stay in one location of most ancient civilisations being between forty to sixty generations or about one thousand to fifteen hundred years. Some ten to thirty civilisations have followed a similar road to ruin. Carter and Dale [1974] outline that the same old story of the rise and fall of ancient civilisations follows in a series of cycles.

Roberts [1995] recognises that Carter and Dale's book 'Topsoil and Civilisation' is a reliable account of the rise and fall of civilisations according to the use or abuse of topsoil. It is noted that there is a lack of material on the history of Chinese agriculture probably because it was predominantly based on a village system and not on the development of large urban civilisations.

Another dominant trend in history is that progressive civilisations have moved to new lands under their control and re-established a new urban civilisation in a new location. Carter and Dale [1974] make a further assumption that civilisations generally decline in the same area that nurtured them, mainly because man despoiled the favourable land and environment in which he tried to sustain a food supply. For the soil bears witness to its own decline, as the process of growing food slowly depletes the resource from whence it came. This would appear to be a self defeating exercise, but history appears to show that decisions made by humanity are supporting this non sustainable process. Carter and Dale [1974] suggest that Northern parts of Africa only support a fraction of the population they did eight centuries ago, when all the local populations were fed and bountiful surpluses justified the area to be called the 'granary of Rome'.

Historians and philosophers seldom write about the relations of people to the land, rather they write about the relations of people with each other. Yet Plato in the Critias considered it worth describing the change in the land of Attica under early Greek settlement. He states:

... what now remains compared with what then existed is like the skeleton of a sick man, all the fat and soft earth having wasted away, and only the bare framework of the land being left. Formally, many of the present mountains were arable hills, the present marshes were plains full of rich soil; hills were once covered with forest, and produced boundless pasturage that now produce only food for bees. Moreover, the land was enriched by yearly rains, which were not lost, as now, but flowing from the bare land into the sea; the soil was deep, it received the water, storing it up in the retentive loamy soil; the water that soaked into the hills provided abundant springs and flowing streams in all districts. Some of the now abandoned shrines, at spots where former fountains existed, testify that our description of the land is true [Carter, Dale, 1974, p.105].

Ancient Greek philosophers considered agriculture as a honourable profession and yet this did not stop farmers from degrading their land. There are few relatively sustainable forms of land use that have come to us from the ancients. The practice of terracing is one example that was often commenced when irrigation or cultivation in the valleys was unsuccessful. Often as irrigation systems failed due to silting, labour intensive terracing on the sloping land was commenced to support the population. The Phoenicians built some of the first known bench terraces, being rock walls that covered thousands of acres to reduce soil erosion [Carter, Dale, 1974]. In summary, it would appear that civilisations and their farmers have not learnt to preserve the main source of food - the soil. Historical records have shown the consistent failure of most ancient agricultural systems to support large urban civilisations for more than forty to sixty generations or about one thousand to fifteen hundred years, with the exception of the areas of Mesopotamia, Indus Valley and the Nile Valley [Carter, Dale 1974]. However, the latter is the only surviving productive agricultural area. It is also evident that in regard to the issue of sustainable agriculture it cannot be separated from the socio-political framework that these systems operated in. A key principle of sustainability is apparent from ancient agriculture in as much that erosion control was essential in all land use. Carter and Dale [1974] have emphasised the erosion of soil from agricultural land has greatly contributed to non-sustainability on non-irrigated land. Savory [1988] holds the view that collapsed civilisations, relying on irrigation, have often resulted from the deterioration of watersheds, rather than the deterioration of croplands.